Progress 01/19/16 to 01/18/21
Outputs
PROGRESS REPORT Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100° to 160°F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC®) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. This is the final report for Project 8072-41420-019-00D, which ended January 18, 2021. New NP108 approved project is entitled ⿿Incidence of bacterial pathogens in regulated foods and applied processing technologies for their destruction. We addressed all milestones for Project 8072-41420-019-00D via productive collaborations with Cooperative Research and Development Agreement/Material Transfer Agreement (CRADA/ MTRA) partners and food safety professionals from academia, government, industry, and consumer groups. Programmatically, we quantified the prevalence, levels, and types of target pathogens along the food chain continuum from farm to flush and developed and validated biological, chemical, and physical interventions to control Listeria monocytogenes (Lm), Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. (Sal) , Trichinella spiralis (Ts) and Toxoplasma gondii (Tg) in a variety of foods. Regarding pathogen presence, we established the comparative recovery rate of STEC in raw, non-intact veal and beef purchased at food retailers in the Mid-Atlantic states in the U.S.: in general, STEC was recovered more frequently from raw veal than beef, and non-O157 STEC were more common than serotype O157:H7 cells. In related experiments, the inability to recover viable cells of STEC displaying serogroup-specific surface antigens for at least one of the seven regulated serogroups of STEC in combination with the stx and eae virulence genes suggests that STEC are not common in the raw ground pork or in marinades (fresh and spent) from specialty grocers or food retailers in the Mid-Atlantic states in the U.S. We also quantified the prevalence of Sal in raw chicken livers from food retailers, research farms, and abattoirs. Whereas the pathogen was recovered quite often from raw chicken livers purchased at food retailers (ca. 60%; 6.4 MPN to 2.4 log CFU/g), Sal was recovered less frequently from livers harvested from birds on a research farm (ca. 5.8%; 0.4 to 2.2 MPN/g) or from livers obtained at a poultry slaughter facility (6.7%). Studies are ongoing to subtype the isolates retained from the abovementioned surveys. As part of a large-scale market basket survey, we used whole-genome sequencing (WGS) to characterize 201 isolates of Lm recovered from 102 of 27,389 (RTE) foods purchased at grocery stores in the U.S. over two years. Although significant differences in genetic diversity were not found following pairwise comparisons of isolates, differences in virulence potential and possible pathogen sources were observed. Collectively, these data provide insight on the true prevalence, levels, and types of pathogens in higher volume and/or higher risk foods, as well as their relatedness, persistence, and source(s) and this, in turn, should lead to better management of pathogens in foods and lower public health risks. Regarding pathogen control and interventions, we monitored the viability or improved the safety and extended the shelf life of raw, further processed, or fermented foods by applying high pressure or heat or treating such products with food-grade chemicals surface agents or ingredients. Antimicrobials were effectively and efficiently delivered into foods as ingredients or onto foods via SLIC® or electrostatic spraying. Examples include the use of organic acids or buffered vinegar, a ⿿clean label food grade chemical, to control Lm in rotisserie chicken salad, uncured turkey breast, mortadella, or ham, as well as monitoring the fate of STEC, Lm, or Sal on slices of prosciutto and pancetta. We also tested if dry/ fermented sausage or dry-cured hams provided a favorable environment for persistence or outgrowth of Ts or Tg during manufacture or during extended (up to 12 months) shelf life. For specialty/ethnic products, we assessed the viability of STEC in ⿿soupie, a homemade soppressata, and in soppressata that we prepared with certified Angus beef, and both sliced retail and bresaola were prepared to validate safe processes for these specialty/ethnic products. We also validated post-fermentative heating temperatures and times to control pathogens in several dry/ fermented sausage types, including pepperoni- and Genoa-type sausage. We also demonstrated that well-established cooking and pressure parameters required to eliminate STEC, Sal, and Lm from ground beef should be as effective for controlling cells of these same pathogens in plant-sourced meat. We also analyzed the effect of experimental parameters such as cooking appliance, volume and type of cooking oil, product formulation, levels and types of antimicrobials, and cooking/fermentation times and temperatures on thermal inactivation of target pathogens in red meat and poultry products. As expected, the higher the temperature and the longer the time for applying heat or fermentation/drying, the greater the reduction in pathogen levels. Lastly, in collaboration with several of our academic partners, we developed a message for the masses media/ marketing campaign (aka ⿿160° is Good) to inform consumers about proper thermometer use and that burgers should be cooked to 160°F. Social media was also used to better educate consumers about real versus perceived food safety risks in retail. These data have real-world application for maintaining the safety of our Nation⿿s food supply via our frequent input from regulators and the food industry and our use of pathogenic strains and pilot-scale processing equipment. Record of Any Impact of Maximized Teleworking Requirement: As a consequence of maximized teleworking status due to the ongoing COVID- 19 pandemic we have been unable to initiate new research projects/ initiatives. It has also prevented us from negotiating CRADA opportunities and competitive grant submissions since we may not be able to deliver on the attendant contractual obligations. The collective results of this challenging situation are that our programmatic efforts are on hold because we are not able to conduct science in our laboratories. ACCOMPLISHMENTS 01 Inactivation of foodborne pathogens within plant burgers in response to heat and pressure. Although plant-based burgers have become increasing popular and more readily available little is known about the safety of such products. Thus, ARS researchers at Wyndmoor, Pennsylvania, conducted research to quantify inactivation of Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes (Lm) within hand- formed plant- and beef-based burgers (ca. 114 g each) subjected to high pressure (HPP; 350 or 600 MPa) or cooked in a saute pan (62.8, 68.3, or 73.9C). Levels of both pathogens were lowered by to 400,000 cells/g via HPP and by ca. 25,000 to 10 million cells/g via cooking. Since both pathogens responded similarly to heat and pressure in plant-based as in beef-based burgers, well-established cooking and HPP parameters required to eliminate STEC or Lm from ground beef should be as effective for controlling cells of these same pathogens in burgers made from a plant-sourced protein. 02 Whole genome comparisons of Listeria monocytogenes isolates recovered from ready-to-eat retail foods. Since Listeria monocytogenes (Lm) is responsible for numerous illnesses and recalls of ready-to-eat (RTE) foods, research is needed to determine the origin, persistence, and relatedness of Lm associated with high-volume, higher-risk RTE foods at retailers. Between 2010 and 2013, ARS researchers at Wyndmoor, Pennsylvania, in collaboration with Food and Drug Administration (FDA) researchers at College Park, Maryland, characterized 201 isolates of Lm recovered from 102 of 27,389 RTE foods purchased at grocery stores in the U.S. as part of the Interagency Market Basket Survey (Lm MBS). To better understand their potential genetic diversity, ARS and FDA scientists performed whole genome sequencing (WGS) analyses of these isolates. Results demonstrated the presence of 29 clones among the 201 isolates, and the full-length virulence gene inlA was present in 89.4% of the isolates. For 91 of 96 food samples tested, both isolates from the same sample were shown to be indistinguishable by WGS. These unique insights into source, clonal groups, and virulence gene profiles in a well-defined set of 201 isolates recovered from selected categories of refrigerated, RTE foods purchased at retail will foster the development of strategies to lower the occurrence of Lm in RTE foods. 03 Inactivation of Toxoplasma gondii in dry-cured ham. Consumption of raw and uncooked pork meat has been associated with transmission of toxoplasmosis; an illness caused by Toxoplasma gondii bradyzoites. Due to the lack of information regarding inactivation of T. gondii bradyzoites during processing of RTE dry-cured meat products, ARS researchers at Wyndmoor, Pennsylvania, in collaboration with ARS researchers in Beltsville, Maryland, investigated the viability of T. gondii in experimentally-infected, dry-cured whole hams processed using methods approved in the U.S. Code of Federal Regulations (9 CFR 318.10) for inactivation of Trichinella spiralis. Results showed that T. gondii bradyzoites were inactivated during the salting and curing step (33 days) for ham manufacture; viable T. gondii were not detected via a mouse bioassay during periodic sampling over the 12-month duration of this experiment. These results demonstrated that the approved protocols for production of dry-cured hams can inactivate T. gondii, lower the risk of toxoplasmosis to consumers, and help industry/processors meet existing regulatory requirements. 04 Post-fermentation heating to control Salmonella in salami. Pathogens such as Salmonella can be recovered from Genoa salami and other fermented sausage, and consumption of fermented meats harboring pathogens has sporadically caused human illness. Thus, ARS researchers at Wyndmoor, Pennsylvania, evaluated the effect of post-fermentation heating times and temperatures in combination with drying on the fate of Salmonella in Genoa salami. After fermentation, chubs were heated to an internal temperature of 46.3 or 48.9C and held for up to 5 h and then dried at 17C for 25 days. Regardless of the post-fermentation heating temperatures and holding times or casing diameter, the endpoint pH after fermentation was ca. pH 4.7. Fermentation alone lowered levels of Salmonella by about 100 cells per gram. Reductions of at least 100, 000 cells of Salmonella were achieved in 2-5 h of post-fermentation heating (46.3 or 48.9C) without adversely affecting product quality. These data provide the industry with time/temperature options to achieve reductions of Salmonella in Genoa salami and meet regulatory requirements without appreciably compromising product quality.
Impacts
(N/A)
Publications
- Levine, K., Luchansky, J.B., Porto Fett, A.C., Bryant, V., Herring, C., Chapman, B. 2020. How food safety savvy are shoppers? Investigating and impacting consumers⿿ risk identification skills at retail. Food Protection Trends. 41:21-35.
- Cope, S.J., Porto Fett, A.C., Luchansky, J.B., Hochstein, J., Chapman, B. 2020. Utiization of quantitative and qualitative methods to investigate the impacts of a pilot media campaign targeting safe cooking techniques and proper thermometer use. Food Protection Trends. 40:332-348.
- Jung, Y., Porto Fett, A.C., Parveen, S., Meredith, J., Shoyer, B.A., Henry, E., Trauger, Z., Shane, L.E., Osoria, M., Schwarz, J., Rupert, C., Chapman, B., Moxley, R., Luchansky, J.B. 2021. Recovery rate of cells of the seven regulated serogroups of shiga toxin-producing Escherichia coli from raw veal cutlets, ground veal, and ground beef from retail stores in the mid-atlantic region of the United States. Journal of Food Protection. 84(2):220-232. https://doi.org/10.4315/JFP-20-290.
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Progress 10/01/19 to 09/30/20
Outputs
Progress Report Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100° to 160°F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC®) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. This project will end January 18, 2021. New NP108 OSQR is entitled ⿿Incidence of bacterial pathogens in regulated foods and applied processing technologies for their destruction and is under revision. We addressed all milestones for Project 8072-41420-019-00D via productive collaborations with CRADA/MTRA partners and food safety professionals from academia, government, industry, and consumer groups. Programmatically, we quantified the prevalence, levels, and types of target pathogens along the food chain continuum from farm to flush and developed and validated biological, chemical, and physical interventions to control Listeria monocytogenes (Lm), Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. (Sal), Trichinella spiralis (Ts), and Toxoplasma gondii (Tg) in a variety of foods. Regarding pathogen presence, we established the comparative recovery rate of STEC in raw, non-intact veal and beef purchased at food retailers in the Mid-Atlantic states in the US: in general, STEC were recovered more frequently from raw veal than beef, and non-O157 STEC were more common than serotype O157:H7 cells. In related experiments, the inability to recover viable cells of STEC displaying serogroup-specific surface antigens for at least one of the seven regulated serogroups of STEC in combination with the stx and eae virulence genes suggests that STEC are not common in raw ground pork or in marinades (fresh and spent) from specialty grocers or food retailers in the Mid-Atlantic states in the U.S. We also quantified the prevalence of Sal in raw chicken livers from food retailers, research farms, and abattoirs. Whereas the pathogen was recovered quite often from raw chicken livers purchased at food retailers (ca. 60%; 6.4 MPN to 2.4 log CFU/g), Sal was recovered less frequently from livers harvested from birds on a research farm (ca. 5.8%; 0.4 to 2.2 MPN/g) or from livers obtained at a poultry slaughter facility (6.7%). Studies are ongoing to subtype the isolates retained from the abovementioned surveys. As part of a large-scale market basket survey, we used whole genome sequencing (WGS) to characterize 201 isolates of Lm recovered from 102 of 27,389 (RTE) foods purchased at grocery stores in the U.S. over a two-year period. Although significant differences in genetic diversity were not found following pairwise comparisons of isolates, differences in virulence potential and possible sources of the pathogen were observed. Collectively, these data provide insight on the true prevalence, levels, and types of pathogens in higher volume and/or higher risk foods, as well as their relatedness, persistence, and source(s) and this, in turn, should lead to better management of pathogens in foods and lower public health risks. Regarding pathogen control and interventions, we monitored the viability or improved the safety and/or extended the shelf life of raw, further processed, and/or fermented foods by applying high pressure or heat or by treating such products with food grade chemicals as surface agents or ingredients. Antimicrobials were effectively and efficiently delivered into foods as ingredients or onto foods via SLIC® or electrostatic spraying. Examples include the use of organic acids and/or buffered vinegar, a ⿿clean label food grade chemical, to control Lm in rotisserie chicken salad, uncured turkey breast, mortadella, or ham, as well as monitoring the fate of STEC, Lm, and/or Sal on slices of prosciutto and pancetta. We also tested if dry/fermented sausage or dry- cured hams provided a favorable environment for persistence or outgrowth of Ts or Tg during manufacture or during extended (up to 12 months) shelf life. For specialty/ethnic products we assessed viability of STEC in ⿿soupie, a home-made soppressata, as well as in soppressata that we prepared with certified angus beef, and both sliced retail and bresaola we prepared, to validate safe processes for these specialty/ethnic products. We also validated post-fermentative heating temperatures and times to control pathogens in several types of dry/fermented sausage, including pepperoni- and Genoa-type sausage. We also demonstrated that well-established cooking and pressure parameters required to eliminate STEC, Sal, and Lm from ground beef should be as effective for controlling cells of these same pathogens in a plant-sourced meat. We also analyzed the effect of experimental parameters such as cooking appliance, volume and type of cooking oil, product formulation, levels and types of antimicrobials, and cooking/fermentation times and temperatures on thermal inactivation of target pathogens in red meat and poultry products. As expected, the higher the temperature and the longer the time for application of heat or fermentation/drying, the greater the reduction in pathogen levels. Lastly, in collaborator with several of our academic partners we developed a message for the masses media/marketing campaign (aka ⿿160° is Good) to inform consumers about proper thermometer use and that burgers should be cooked to 160°F. Social media was also used to better educate consumers about real versus perceived food safety risks in a retail setting. These data have real world application for maintaining the safety of our Nation⿿s food supply via our frequent input from regulators and the food industry and our use of pathogenic strains and pilot-scale processing equipment. Accomplishments 01 Eliminating pathogens within plant burgers using heat and high pressure. Interest in plant-based burgers has grown appreciably in recent years. While some information is available on the sensory and quality attributes, little is known as to the safety of such products. Research by ARS scientists at Wyndmoor, Pennsylvania, showed that cooking burgers in a saute pan or treating burgers with high pressure significantly lowered levels of Listeria monocytogenes and toxigenic Escherichia coli. In fact, both pathogens responded similarly to heat and high pressure in plant-and beef-based burgers. These findings confirmed that well-established cooking and pressurization treatments for ground beef are equally effective for ensuring the safety of burgers made from a plant-sourced protein. 02 Characterization of Listeria monocytogenes recovered from ready-to-eat (RTE) foods. Listeria monocytogenes (Lm) is a common and deadly pathogen that is found on a variety of RTE foods. Additional data are needed to determine the source and relatedness of Lm associated with high-volume, higher-risk RTE foods from grocery stores. Between 2010 and 2013, ARS researchers at Wyndmoor, Pennsylvania, in collaboration with Food and Drug Administration (FDA) researchers at College Park, Maryland, conducted DNA fingerprinting on 201 isolates of Lm recovered from 102 of 27,389 foods purchased at representative grocery stores in the U.S. The results established the relatedness of all isolates and provided unique insights on the sources of this pathogen between and among foods and stores. These findings will lead to better strategies to lower the risk of listeriosis prior to human contact or consumption with Lm. 03 Inactivation of parasites in dry-cured ham. Consumption of raw and uncooked pork meat has been associated with transmission of toxoplasmosis, a serious illness caused by Toxoplasma gondii. Because of the sporadic presence of T. gondii in pork meat, consumption of some pork products may present a potential risk for transmission of toxoplasmosis. In collaboration with ARS researchers at Beltsville, Maryland, ARS researchers at Wyndmoor, Pennsylvania, monitored viability of T. gondii in experimentally-infected, dry-cured whole hams processed using standard methods. T. gondii was inactivated during the early stages of ham manufacture and was not detected during periodic sampling over the 12-month duration of this experiment. Thus, approved protocols for production of dry-cured hams validated can lower the risk of toxoplasmosis to consumers and help industry/processors meet existing regulatory requirements. 04 Application of heat to control pathogens in Genoa salami. Pathogens such as Salmonella can be recovered from Genoa salami, and consumption of fermented meats harboring such pathogens has sporadically caused human illness. Traditional processes for preparing Genoa salami may not be effective to inactivate pathogens to the extent necessary to meet statutory requirements, and without affecting product quality. Thus, ARS researchers at Wyndmoor, Pennsylvania, evaluated the effect of post- fermentation heating times and temperatures in combination with drying on the fate of Salmonella in Genoa salami. Researchers heated salami just after fermentation, which combined with the typical drying regimen for Genoa, lowered levels of Salmonella. These data provide the industry with time/temperature options to kill Salmonella in Genoa salami and to meet regulatory requirements without appreciably compromising product quality. 05 High-pressure processing of meatballs to control pathogens. Consumption of under-processed and improperly handled or stored meat products contaminated with Escherichia coli (E. coli) that produce Shiga toxins are responsible for numerous illnesses, hospitalizations, and deaths each year. Over the past 20 years, multiple recalls and illnesses were linked to raw ground beef, and recent recalls were also linked to meatballs. ARS scientists at Wyndmoor, Pennsylvania, used high-pressure processing to inactivate toxigenic E. coli in raw meatballs. Using high- pressure treatment to kill pathogen in raw meatballs will lower the public health risk from toxigenic E. coli.
Impacts
(N/A)
Publications
- Luchansky, J.B., Shoyer, B.A., Jung, Y.N., Shane, L.E., Osoria, M., Porto Fett, A.C. 2020. Viability of Shiga Toxin-producing Escherichia coli, Salmonella, and Listeria monocytogenes within plant burgers and beef burgers during cold storage and following pan frying. Journal of Food Protection. 83(3):434-442.
- Porto Fett, A.C., Shane, L.E., Shoyer, B.A., Osoria, M., Jung, Y.N., Luchansky, J.B. 2020. Viability of cells of shiga-toxin producing Escherichia coli and Listeria monocytogenes within plant-sourced versus beef-sourced protein samples in response to high pressure. Journal of Food Protection.
- Porto Fett, A.C., Jackson-Davis, A., Kassama, L., Daniel, M., Oliver, M., Jung, Y.N., Luchansky, J.B. 2020. Inactivation of Shiga toxin-producing cells of Escherichia coli in refrigerated and frozen meatballs using high pressure processing. Microorganisms.
- Chen, Y., Chen, Y., Pouillot, R., Dennis, S., Xian, Z., Luchansky, J.B., Porto Fett, A.C., Lindsay, J.A., Allard, M., Brown, E., Van Doren, J.M. 2020. Genetic diversity and virulence gene profiles of Listeria monocytogenes isolates from the 2010-2013 interagency market basket survey. PLoS One.
- Jackson-Davis, A., Daniel, M., Luchansky, J.B., Porto Fett, A.C., Kassama, L. 2019. The efficacy of ultrasound on the inactivation of Shiga toxin- producing Escherichia coli in raw beef trim. Foods. 2(5).
- Jung, Y.N., Porto Fett, A.C., Shoyer, B.A., Shane, L.E., Henry, E.D., Osoria, M., Luchansky, J.B. 2019. Survey of intact and non-intact raw pork collected at retail stores in the mid-Atlantic region of the United States for the seven regulated serogroups of Shiga toxin-producing Escherichia coli. Journal of Food Protection. 82.
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Progress 10/01/18 to 09/30/19
Outputs
Progress Report Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100° to 160°F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC®) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. We continue to make measurable progress on our stated milestones via productive collaborations with CRADA partners and food safety professionals from academia, government, industry, and consumer groups. Programmatically, we quantified the prevalence, levels, and types of target pathogens along the food chain continuum from farm to flush and developed and validated biological, chemical, and physical interventions to control Listeria monocytogenes (Lm), Shiga toxin-producing Escherichia coli (STEC), and Salmonella spp. (Sal) in a variety of foods. Regarding the former, we established the recovery rate of STEC in raw, non-intact veal and beef purchased at food retailers in the Mid-Atlantic states in the U.S. In related experiments, the inability to recover viable cells of STEC displaying serogroup-specific surface antigens for at least one of the seven regulated serotypes of STEC in combination with the stx and eae virulence genes suggested that STEC are not common in raw marinades (fresh and spent) from specialty grocers or in raw, non-intact pork obtained from grocery stores in NC, PA, DE, or NJ. We also quantified the prevalence of Sal in raw chicken livers from food retailers, research farms, and abattoirs. Whereas the pathogen was recovered quite often from raw chicken livers purchased at food retailers (ca. 60%; 6.4 MPN to 2.4 log CFU/g), Sal was recovered far less frequently from livers harvested from birds on a research farm (ca. 5.8%; 0.4 to 2.2 MPN/g) or from livers obtained at a poultry slaughter facility (6.7%). Studies are ongoing to subtype the isolates retained from the abovementioned surveys. Collectively, these data provide insight on the true prevalence of pathogens in higher volume and/or higher risk foods, as well as their levels and types, and lead to better management of pathogens and lower public health risks. Regarding pathogen control and interventions, we monitored the viability or improved the safety and/or extended the shelf life of raw, further processed, and/or fermented foods by applying high pressure or heat or by treating such products with food grade chemicals as surface agents or ingredients. Examples include the use of buffered vinegar, a ⿿clean label food grade chemical, to control Lm in rotisserie chicken salad, monitoring the fate of STEC, Lm, and/or Sal on slices of a dry-cured meat to determine if such products provide a favorable environment for persistence or outgrowth of these pathogens during the extended (up to 12 months) shelf life, and assessing viability of STEC in ⿿Soupie, a home-made soppressata, to validate safe processes for this specialty/ethnic product popular in the coal regions of PA. These experiments analyzed the effect of experimental parameters such as cooking appliance, volume and type of cooking oil, product formulation, levels and types of antimicrobials, and cooking/fermentation times and temperatures. As expected, the higher the temperature and the longer the time for application of heat or fermentation/drying, the greater the reduction in pathogen levels. These data have real world application for maintaining the safety of our Nation⿿s food supply via our frequent input from regulators and the food industry and our use of pathogenic strains and pilot-scale processing equipment. Accomplishments 01 Prevalence of Salmonella spp. in/on raw chicken livers. There was demonstrable increase in chicken liver-associated outbreaks over the last 10 years due to Campylobacter and Salmonella. To assess the potential for further outbreaks from liver, ARS researchers in Wyndmoor, Pennsylvania, surveyed 249 raw chicken livers from food retailers for the presence and levels of Salmonella. The pathogen was recovered from 148 of 249 (59.4%) chicken livers purchased at retail stores in DE, NJ, and PA over an about 9-month period; pathogen levels ranged from 6.4 MPN/g to 2.4 log CFU/g. Of note, researchers were more likely (P = 0. 019) to recover Salmonella from livers that were packaged by retailers (81 of 121 livers; 66.9%) compared to those packaged directly by processors (67 of 128 livers; 52.3%). Although proper cooking would eliminate low levels of Salmonella in/on raw chicken livers, further interventions for processors are needed to lower the prevalence and levels of this pathogen on poultry liver. Thus, these data will assist the industry in producing safer chicken products, therby protecting the health of the American consumer. 02 Screening raw, non-intact pork for Shiga toxin-producing Escherichia coli (STEC). Although pork is not a common vehicle for food borne illness due to STEC, over the last 25 years there have been a handful of STEC outbreaks caused by pork products. Thus, ARS researchers in Wyndmoor, Pennsylvania, screened 514 raw pork samples (395 ground/non- intact and 119 intact samples) purchased at grocery stores in New Jersey, Delaware, and Pennsylvania, between July and December of 2017 to assess the recovery rate of cells of the seven regulated serogroups of STEC (STEC-7; O26, O45, O103, O111, O121, O145, or O157:H7). Using a PCR-based method for screening purposes, 5.3% (21 of 395 samples) of the non-intact and 3.4% (3 of 119 samples) of the intact pork samples tested positive for the requisite virulence genes (i.e., stx and eae) and for the somatic O antigens for at least one of the targeted STEC serogroups: zero of these 24 presumptive positive pork samples subsequently yielded a viable isolate of STEC displaying a STEC-7 serogroup-specific surface antigen along with the stx and eae genes. These data suggest that STEC-7 are not common in retail raw pork samples in the Mid-Atlantic region of the U.S. Thus, these results will be useful for assisting the industry to develop strategies to lower the risks of STEC attributed to pork products, and in turn, enhancing the safety of our Nation⿿s food supply. 03 Analysis of marinades from food retailers for Shiga toxin-producing Escherichia coli (STEC). STEC have caused human illness from ingestion of poorly stored, handled, processed, or prepared raw beef products, including both non-intact and marinated products. To better quantify the recovery rate and attendant risk of STEC from such products, ARS researchers at Wyndmoor, Pennsylvania, in collaboration with collaborators at North Carolina State University (NCSU), screened marinades from food retailers for the presence of cells of the seven regulated serotypes of STEC. Of 115 marinade samples (58 fresh marinades and 57 spent/used marinades) collected over 52 weeks from four food retailers within 60 miles of NCSU, zero samples tested positive for STEC using a PCR-based method. Thus, although our findings would suggest that marinades do not present an appreciable risk from STEC, retailers must continue to prepare and maintain marinade solutions and meat at 4 deg C or less, as well as frequently and properly clean and disinfect the equipment and environment in both the processing area and deli case to ensure the safety and quality of red meat and poultry products subjected to marinization for the purposed of enhancing tenderness or flavor. These results will assist the industry and food retailers to mitigate critical risk factors associated with the marination process and marinade formulation, so that contaminated meats are not available for purchase by consumers. 04 Inactivation of Shiga toxin-producing Escherichia coli (STEC) in meat bars. Consumer preferences for foods that are more healthy, lower in calories, and higher in protein have fueled the development of meat- based snack products such as meat bars, a nutrient-dense, protein-rich, hand held portable snack food. Although very popular among consumers, relatively little data has been published to establish if meat bars can support the growth or survival of microbial pathogens, if present, during preparation, handling, or extended storage. Thus, ARS researchers at Wyndmoor, Pennsylvania, mentored and collaborated with student interns to validate commercially-relevant formulations and time/ temperature dehydration conditions for lethality of STEC in meat bars. Meat bar batter (i.e., ground beef, pecans, flaxseed flour, cranberries, sunflower seeds, sea salt, black pepper, and celery powder) prepared with or without encapsulated citric acid (ECA) was inoculated with an eight-strain cocktail of cells of STEC to a target level of 3.0 million cells per gram of meat bar. Meat bars (40 g each) were separately cooked/dried, without the addition of humidity, in a commercial, stainless-steel dehydrator set at either 62.8 deg C for 6 h, 71.1 deg C for 4 h, or 62.8 deg C for 2 h and then at 71.1deg C for 2 h. Regardless of formulation, the cooking/drying time/temperature regimens tested herein resulted in reductions of ca. greater than 160,000 cells of STEC per gram. This study provides valuable information for producers and policy makers to enhance the safety of this expanding line of high-protein, meat-based, snack products. 05 Behavior of food pathogens in a specialty, dry-cured beef product. Dry- cured, ready-to-eat (RTE) meats are an increasingly popular food choice, but there is a scarcity of information about the microbiological safety of such products. Thus, ARS researchers at Wyndmoor, Pennsylvania, monitored the behavior of multi-strain cocktails of cells of Listeria monocytogenes (Lm) or Shiga toxin-producing Escherichia coli (STEC) on bresaola, an Italian dry-cured beef product, during extended storage at refrigeration and abusive temperatures. In brief, two slices (ca. 8 g each) of commercially-sliced bresaola were layered horizontally into a nylon-polyethylene bag and then inoculated with a multi-strain cocktail of STEC or Lm to a target level of 1,000 cells per slice. Bags were vacuum-sealed and stored at 4 or 10 deg C. Bresaola did not support growth of Lm or STEC during extended storage: pathogen numbers decreased by ca. 15 to 65 cells per package after 150 or 90 days when bresaola was stored at 4 or 10 deg C, respectively. Thus, bresaola does not provide a favorable environment for outgrowth of Lm or STEC if present on the surface from inadequate processing and/ or post-process contamination. These data will assist the food industry and regulatory agencies for both enhancing and assuring microbial food safety of the American food supply.
Impacts
(N/A)
Publications
- Jung, Y.N., Porto Fett, A.C., Shoyer, B.A., Henry, E.D., Shane, L.E., Osoria, M., Luchansky, J.B. 2019. Prevalence, levels and viability of Salmonella in/on raw chicken livers. Journal of Food Protection. 82(5):834- 843.
- Shane, L.E., Porto Fett, A.C., Shoyer, B.A., Phebus, R.K., Thippareddi, H. , Hallowell, A.M., Miller, K., Foster-Bey, L., Campano, S.G., Taorimina, P. , Glowski, D., Tompkin, R.B., Luchansky, J.B. 2018. Effect of fermentation and post-fermentation heating times and temperatures for controlling Shiga toxin-producing Escherichia coli in a dry-fermented-type sausage. Italian Journal of Food Safety.
- Hill, D.E., Luchansky, J.B., Porto Fett, A.C., Gamble, H., Urban Jr, J.F., Fournet, V.M., Hawkins Cooper, D.S., Gajadhar, A., Holley, R., Juneja, V. K., Dubey, J.P. 2018. Rapid inactivation of Toxoplasma gondii bradyzoites in dry cured sausage. Food and Waterborne Parasitology.
- Porto Fett, A.C., Shoyer, B.A., Shane, L.E., Osoria, M., Henry, E.D., Jung, Y.N., Luchansky, J.B. 2019. Thermal inactivation of Salmonella spp. in pate made from chicken livers. Journal of Food Protection. 82(6):980- 987.
- Luchansky, J.B., Mayhew, M., Jung, Y.N., Klinedinst, A., Harkins, L., Shane, L.E., Osoria, M., Mcgeary, L., Traugher, Z., Shoyer, B.A., Chapman, B., Cope, S.J., Campano, S.G., Porto Fett, A.C. 2019. Fate of Shiga toxin- producing Escherichia coli in meat bars during processing and storage: a consumers' perspective. Journal of Food Protection. 82(7):1249-1264.
- Fredericks, J.N., Hawkins Cooper, D.S., Hill, D.E., Luchansky, J.B., Porto Fett, A.C., Gamble, H.R., Fournet, V.M., Urban Jr, J.F., Gajadhar, A.A., Holley, R., Dubey, J.P. 2019. Low salt exposure results in inactivation of Toxoplasma gondii bradyzoites during formulation of dry cured ready-to-eat pork sausage. Food and Waterborne Parasitology. 15:e00047.
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Progress 10/01/17 to 09/30/18
Outputs
Progress Report Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100� to 160�F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC�) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. Progress was made possible by our many and valued collaborations with CRADA partners and food safety professionals from academia, government, industry, and consumer groups. The primary focus of our research has and continues to be the development and validation of biological, chemical, and physical interventions to control Listeria monocytogenes (Lm), Shiga toxin-producing Escherichia coli (STEC), and Salmonella spp. (Sal) in a variety of foods. These efforts included validating high pressure processing and cooking to reduce the levels of Sal in/on poultry livers and pate. These efforts also included the use of buffered vinegar, a �clean label� food grade chemical, to reduce levels and/or prevent outgrowth of Lm during extended refrigerated storage of ready-to-eat (RTE) , fully-cooked, uncured pork breakfast patties. In the absence of antimicrobials, pathogen numbers increased by ca. 630,000 cells per gram after 90 days at 4 deg C. When 1.5% or 2.0% BV were added to the formulation, pathogen numbers decreased by only ca. 4 cells per gram after 90 days at 4 deg C, whereas Lm numbers remained relatively unchanged during of 180 days at -20 deg C. In the event of post-process contamination, inclusion of 1.5% of BV would be effective as a clean label ingredient for inhibiting outgrowth of Lm on fully-cooked, uncured pork patties during extended refrigerated storage. We also expanded our efforts to deliver antimicrobials into/onto foods via the Spray Lethality in Container (SLIC) and air assisted electrostatic spray (ESS) technologies. These delivery strategies save time and money, as well as increase efficiency. At the suggestion of USDA-FSIS, we conducted surveys of raw and RTE foods, including ground pork, beef and poultry, frozen vegetables, marinades, and salads, purchased at retail grocery stores to assess the �true� prevalence of Sal, STEC, and Lm, as well as to gain insight on their levels and types present in samples testing positive. Studies are ongoing to conduct proximate analyses of representative food samples. Considerable efforts and resources were also directed to establish time and temperature parameters to maximize thermal inactivation of STEC and Sal in raw and further processed red meat and poultry products such as dry-fermented sausage, ground poultry, and livers/pate. Parameters tested included cooking appliance, volume and type of cooking oil, product formulation, and various cooking times and temperatures. As expected, the higher the temperature and the longer the time for application of heat, the greater the reduction in pathogen levels. Of note, since we engage both regulators and the industry as part of the planning, conduct, and data analyses, and since we utilize pathogenic strains and pilot-scale processing equipment, our data are of immediate use to academicians, policy makers, and the food industry for enhancing the wholesomeness of our food supply and improving public health in general. Accomplishments 01 Interventions to improve food safety at retail stores. Food safety hazards at retail food stores as identified by experts are often quite different from what consumers perceive as a hazard/risk. Past research to change consumer perspectives about such risks relied primarily on surveys, interviews, and focus groups to assess attitude, aptitude, and self-reported behavior data; however, past efforts did not measure consumer perceptions and action in real time at retail food stores. In collaboration with scientists at North Carolina State University, ARS researchers at Wyndmoor, Pennsylvania, developed and field tested a series of videos to help consumers identify potential food safety risks while shopping. Among the 66 citizen scientists who collected data while shopping, both before and after viewing the training videos, more hazards were identified in agreement with the assessment of a food safety professional/expert after seeing the video (n = 9, 82%) compared to the baseline (n=2, 18%). Also, participants who viewed the videos agreed with the expert assessment 17% of the time compared to 12% (n=4) for the control group. These findings confirm that videos about food safety hazard identification at retail food stores may improve the ability of consumers to identify potential food safety hazards while grocery shopping. 02 Recovery of pathogenic Escherichia coli from retail ground meats. Shiga toxin-producing Escherichia coli (STEC) pose a serious threat to public health. Cells of STEC are somewhat frequently found on raw meat and have been the cause of numerous recalls and several illnesses over the last 35 years due to undercooked and/or improperly prepared or mishandled beef and veal products. Based on a very limited sampling set, the USDA-FSIS reported a higher risk associated with raw ground beef components (RGBC) derived from veal compared to beef. Thus, ARS researchers in Wyndmoor, Pennsylvania, collected 555 samples of raw ground veal and 540 of beef at retail stores over a 2-year period from across the mid-Atlantic region of the U.S. to establish the comparative �true� prevalence of the 7 regulated serotypes of STEC in veal and beef. Similar to data reported by USDA-FSIS based on a limited number of samples, the recovery rate for non-O157 STEC in retail ground veal was appreciably higher than in ground beef and, thus, systematic interventions should be implemented across the food chain continuum to reduce the risk of STEC cells associated with veal products. 03 Interventions for poultry liver and pate. Chicken livers may harbor pathogens such as Salmonella both on the outside surface and within the organ itself. Poultry liver is frequently used in the preparation of pate, but based on consumer preferences for taste and texture, it may be undercooked. ARS researchers in Wyndmoor, Pennsylvania, evaluated high pressure processing (HPP) and cooking as interventions for Salmonella on/in liver or pate. Raw chicken liver or pate (i.e., livers, eggs, saut�ed onion, salt, pepper, and butter) were inoculated with a multi-strain cocktail of cells of Salmonella to a target level of 6.5 million cells per gram and treated with high pressure for 5 minutes. Reductions in the number of cells for Salmonella were observed in both liver and pate. Also, cooking pate to 60 to 73.8 deg C in a thermostatically-controlled, circulating water bath delivered reductions in the number of cells per gram of Salmonella. Results confirmed that longer times along with higher temperatures or higher pressure delivered greater reductions of the pathogen. Thus, both HPP and heat can appreciably reduce the levels of Salmonella inoculated on/ in chicken liver or pate and, in turn, lower the risk of salmonellosis associated with consumption of undercooked chicken liver and/or pate prepared therefrom.
Impacts
(N/A)
Publications
- Jung, Y.N., Rupert, C., Chapman, B., Porto Fett, A.C., Luchansky, J.B. 2018. Assessment of the microbiological safety and quality of marinades collected over a 12-month period from specialty retailers near Raleigh, North Carolina. Journal of Food Protection. 81:490-496.
- Hill, D.E., Luchansky, J.B., Porto Fett, A.C., Gamble, H., Juneja, V.K., Fournet, V.M., Hawkins Cooper, D.S., Holley, R., Gajadhar, A., Dubey, J.P. 2017. Curing conditions to inactivate Trichinella spiralis muscle larvae in ready-to-eat pork sausage. Food and Waterborne Parasitology. 6:1-8.
- Ghazzi, M., Porto Fett, A.C., Ayas, N.D., Ozansoy, G., Cufaoglu, G., Goncuoglu, M., Dluzneski, A., Holinka, S., Shoyer, B.A., Shane, L.E., Stahler, L., Campano, S., Luchansky, J.B. 2018. Molecular characterization of �ig k�fte sold at retail in Ankara, Turkey, and evaluation of selected antimicrobials as ingredients to control foodborne pathogens in �ig k�fte during refrigerated storage. Food Control. 84:138-147.
- Hasty, J.D., Henson, J.A., Acuff, G.R., Burson, D.E., Luchansky, J.B., Sevart, N.J., Phebus, R.K., Porto Fett, A.C., Thippareddi, H. 2018. Validation of a hot water rinse and lactic acid spray in combination with scaling for treating hide-on carcasses to control biotype I strains of Escherichia coli used as surrogates for Shiga toxin-producing E. coli. Journal of Food Protection. 81:762-768.
- Porto Fett, A.C., Campano, S.G., Rieker, M., Stahler, L.J., Mcgeary, L., Shane, L.E., Shoyer, B.A., Osoria, M., Luchansky, J.B. 2018. Behavior of listeria monocytogenes on mortadella formulated using a natural, clean- label antimicrobial during extended storage at 4 or 12C. Journal of Food Protection. 81:769-775.
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Progress 10/01/16 to 09/30/17
Outputs
Progress Report Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100� to 160�F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC�) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. Progress was made on all objectives, all of which fall under NP108 �Food Safety, Component 1 Foodborne Contaminants; Problem Statement 5. Intervention and Control Strategies, Including Mycotoxins. We continue to benefit from and nurture our longstanding and impactive collaborations with research partners from academia, government, industry, and consumer groups in the conduct of our research to recover, characterize, and control target bacterial and parasitic pathogens in both higher volume/risk and specialty/ethnic foods. Our collaborators include various CRADA, RSA, and MTRA partners, as well as producers, processors, regulators, technology providers, consumer groups, and academicians with the shared interest in enhancing the safety of our Nation�s food supply. Our collective efforts have resulted in numerous tangible outcomes. Examples of our current research includes studies to develop and validate biological, chemical, and physical interventions to control Listeria monocytogenes (Lm), Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. (Sal), Trichinella spiralis (TS), and/or Toxoplasma gondii (TG) in or on a variety of raw, fermented, cooked, and further processed foods, including non-intact products, as well as ready- to-eat (RTE) foods. One example is a process validation study on the inclusion of food grade chemicals in/on frankfurters to control Lm during extended refrigerated/frozen storage. Another example of a process validation study is the use of buffered vinegar, a �clean label� food grade chemical, to reduce levels and/or prevent outgrowth of Lm during storage of mortadella, a Italian-style RTE delicatessen meat. In addition to optimizing the levels and placement of antimicrobials into/onto target foods, we continue to exploit the Sprayed Lethality in Container (SLIC) and air assisted electrostatic spray (ESS) technologies to deliver antimicrobials to foods, such as beef subprimals and raw chicken breasts, at lower costs along with lower volumes and superior coverage compared with more traditional antimicrobial dips and sprays. Considerable efforts and resources were also directed to establish time and temperature parameters to maximize thermal inactivation of STEC and Sal in raw and further processed red meat and poultry products, including non-intact products, such as dry-fermented sausage, ground poultry, subprimals, and meat bars. The combined effects of lowering of pH, increasing time and temperature of cooking, and decreasing water activity were further elaborated in these latter studies. As expected, the higher the temperature and the longer the time for application of heat, the greater the reduction in pathogen levels. In related studies, in collaboration with ARS scientists, we quantified viability of TG and TS in a pepperoni- type fermented sausage made form pork harvested from swine that were inoculated with the above mentioned parasites. As a final example of our progress, we conducted large scale and multi-institutional surveys of higher-volume, higher-risk retail foods, notably cig kofte from Ankara, Turkey, and raw veal from the mid-Atlantic region of the United States, to determine the recovery rate, levels, and harborage points for Lm, Sal, and STEC. Multiple isolates retained from each sample testing positive for a target pathogen were subtyped and characterized for pathogenic potential and survival attributes. Lastly, it should be noted that our process validation studies facilitate taking our findings to real-world abattoirs and processing plants in support of food safety programs because we use pathogenic strains and pilot-scale processing equipment, we inoculate and process real/entire foods rather than simulated or re- structured products, and we seek industry guidance and regulator participation throughout the planning, conduct, and dissemination phases. Thus, our research has immediate practical use and direct implementation by the industry and a focused and positive impact on public health in general. Accomplishments 01 Food safety at grocery stores. Retail grocery store shoppers and employees view food safety risks differently than food safety experts and as a result may be at higher risk for becoming sick. In collaboration with scientists at North Carolina State University, ARS researchers at Wyndmoor, Pennsylvania, collected about 120 digital photographs at grocery stores in California, Maryland, Connecticut, and Georgia of both possible and actual food safety risk situations. As examples, photographs captured utensils, such as tongs, placed handle- down in containers of uncovered foods that are ready-to-eat, bare- handed contact of deli meat during slicing, and water dripping from the ceiling onto the deli counter. These digital photographs can be used as a motivation and as a real-world teaching tool to better inform shoppers and employees at grocery stores of good practices. 02 Control of Shiga toxin-producing Escherichia coli (STEC) surrogates on veal carcasses. Results collected by the USDA suggest there are more Shiga toxin-producing Escherichia coli (STEC) on veal products than on beef products. As part of a multi-institutional team that included Kansas State University, University of Nebraska-Lincoln, and Texas A&M University, ARS researchers at Wyndmoor, Pennsylvania, tested lactic acid (4.5%, pH 2.0), a blend of hydrochloric and citric acids (pH 1.2), and a blend of lactic and citric acids (2.25%, pH 2.3) on veal carcasses to eliminate a combination of E. coli strains that are similar to STEC except not pathogenic. A standard water wash (about 50degC) reduced the E. coli population by 8 cells per cm square on the veal carcasses. All three antimicrobial sprays applied to pre-rigor carcasses delivered an additional reduction of 5 cells of E. coli per cm square, whereas chilling of carcasses for 24 h reduced the surrogate population by only an additional 3 cells per cm square. This study demonstrated that warm water washing, followed by a pre-chill spray treatment with the chemicals tested in this study, can improve the safety of veal carcasses. 03 Control of Listeria monocytogenes (Lm) on clean label/natural ready-to- eat (RTE) meats. Not much information has been published on the effectiveness of natural antimicrobials to eliminate pathogens on specialty/ethnic RTE meats. In collaboration with our CRADA partners, ARS researchers at Wyndmoor, Pennsylvania, conducted research to determine if buffered vinegar (BV) or a blend of potassium lactate and sodium diacetate (KLac) were effective to control Lm on freshly- manufactured mortadella. This bologna-like product was formulated with or without 1.0 or 1.5% of liquid BV (LBV), 0.6 or 1.0% of dry BV (DBV), or 2.5% of KLac, inoculated with ca. 6,500 cells of Lm per slice, and then stored refrigerated. In the absence of antimicrobials, Lm numbers increased by ca. 200 cells/slice after 120 days at 4 deg C. With inclusion of LBV, DBV, or KLac as ingredients, pathogen numbers decreased by ca. 2 to 10 cells per slice after 120 days at 4 deg C. Inclusion of 1% LBV or DBV, as clean label ingredients, in mortadella is equally effective as 2.5% KLac (10 cells reduction) to control Lm on mortadella during proper refrigerated storage. 04 Ensuring the safety of fuet, a Spanish-style fermented sausage. Foodborne pathogens such as Salmonella spp. (Sal), Shiga toxin- producing Escherichia coli (STEC), and Listeria monocytogenes (Lm) may survive in some fermented meats. In collaboration with our CRADA partners, ARS researchers at Wyndmoor, Pennsylvania, conducted research on the survivability of cells of Sal, Lm, and STEC in fuet. Ground pork (30% fat) was mixed with salt (2.5%), starter culture, and spices, and then inoculated with a pool of cells (ca. 6 million cells) of either STEC, Sal, or Lm. This inoculated meat batter was stuffed into casings, fermented at 23 +/- 2 deg C and ca. 95 +/- 4% relative humidity (RH) to ca. pH 5.3, and then dried (12 +/- 2 deg C and ca. 75-85% RH to a water activity of 0.86 or 0.89). The results showed total reductions of greater than 12,500 to 200,000 cells per gram of all three pathogens were achieved after drying. These data will assist manufacturers with ensuring that fuet is wholesome. 05 Inactivation of Trichinella spiralis in dry-cured pork sausage. Although trichinosis from ingestion of raw or uncooked pork remains a problem worldwide, little information is available on how to inactivate Trichinella in fermented products. In collaboration with ARS researchers at Beltsville, Maryland, ARS researchers at Wyndmoor, Pennsylvania, evaluated the anti-trichinae effect of salt, moisture, pH, and temperature during fermentation and drying of a dried-cured pork sausage. Results demonstrated that salt concentrations above 1.3%, in combination with fermentation to pH 5.2 or below, inactivated greater than 96% of Trichinella larvae within 24 to 28 h. After 7 to 10 days of drying, Trichinella were inactivated. The process for making pork sausage as tested in this study was effective for killing Trichinella spiralis, and can be used by meat processors to make sure their products are safe.
Impacts
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Publications
- Luchansky, J.B., Chen, Y., Porto Fett, A.C., Pouillot, R., Shoyer, B.A., Johnson-Derycke, R., Eblen, D.R., Shaw, W.K., Van Doren, J.M., Catlin, M., Lee, J., Tikekar, R., Gallagher, D., Lindsay, J.A., Adams, A., Agnella, S., Akingbade, D., Ayala, A., Baker, E.G., Barlow, K., Bauer, N., Benjamin, L. A., Berry, K., Call, J.E., Campano, S.G., Cook, V., Gallagher, D., Gathercole, L., Ghazzi, D., Govoni, J.A., Hay, G., Harvey, C., Hoelzer, K., Kanjanakorn, A., Kause, J., Khokhar, S., King, J., Klein, V., Lopez, J., Martino, K., Mbandi, E., Murphy, M., Nasella, J., Nguyen, T., Oryang, D., Osoria, M., Papadakis, L., Rajakumar, A., Reed, C., Same, M., Shane, L., Spurlino, C.A., Starks, H.E., Torrence, M.E., Williams, L., Wadsworth, S., Wyszkowski, K., Yoo, K., Dennis, S. 2017. Survey for Listeria monocytogenes on ready-to-eat foods from retail establishments in the United States (2010-2013): assessing potential changes of pathogen prevalence and levels in a decade. Journal of Food Protection. 80:903-921.
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Progress 10/01/15 to 09/30/16
Outputs
Progress Report Objectives (from AD-416): 1: Determine the prevalence, levels, types, and locations of pathogens at various points from production through to consumption of raw, further processed, and/or RTE foods. 1.1. Determine the prevalence and levels of L. monoctyogenes, STEC, and Salmonella spp. in RTE foods at retail, as well as at abattoirs/ processing plants. 1.2. Determine the relatedness of L. monoctyogenes, STEC, and Salmonella spp. recovered from foods using molecular typing methods such as PFGE and MLGT. 1.3. Assess perceptions, food safety attitudes, and self-reported behaviors related to observed food safety hazards by consumers who shop at grocery stores. 2: Develop, optimize, and validate processing technologies for eliminating pathogens. 2.1 - Determine the transfer and survival of STEC and Salmonella spp. in ground and tenderized (i.e., non-intact) red meat, pork, pet, and poultry products. 2.2 - Determine cook dwell times for ground poultry products using common consumer preparation methods such as cooking on gas or electric grills at internal instantaneous temperatures ranging from 100� to 160�F for lethality towards Salmonella and STEC and for consumer acceptability. 2.3 - Determine the effectiveness of food grade antimicrobials applied via electrostatic spray and Sprayed Lethality in Container (SLIC�) methods on pork offal and on chicken necks and frames for control of Salmonella and STEC. 2.4 - Validate fermentation and cooking of dry-fermented sausages for control of STEC, Salmonella, and other pathogens. 3: Develop and/or validate strategies to deliver antimicrobials to raw and packaged foods from production through to consumption to control L. monocytogenes, STEC, Salmonella spp., and other pathogens. Approach (from AD-416): We will exploit the tools of microbiology, molecular biology, and food science to recover, characterize, and control food borne pathogens from production through to consumption for a variety of foods, with emphasis on specialty/ethnic and higher volume, higher risk foods. We will identify where pathogens enter the food supply, determine how they persist, and investigate biological, chemical, and physical interventions to eliminate or better manage them to improve public health. The target pathogens of greatest concern for this project are Listeria monocytogenes, Salmonella spp., Shiga toxin-producing Escherichia coli, Trichinella spiralis, and Toxoplasma gondii. Targeted foods would include, but not be limited to, raw and ready-to-eat (RTE) meat, poultry, pet, and dairy foods, as well as raw and further processed non-intact meats. One focus of the proposed research is to identify sources and niches of the above mentioned pathogens in foods and food processing environments, as well as at retail and food service establishments, to gain insight on factors contributing to their survival and persistence. Multiple isolates recovered from each sample testing positive from such surveys will be retained for further characterization by phenotypic and genotypic (e.g., pulsed-field gel electrophoresis, PCR-based methods, and/or whole genome sequencing) methods to establish relatedness of isolates and their source and succession. As another focus of our research, efforts will be made to validate processes and interventions such as fermentation, high pressure processing, food grade chemicals, and heat, alone or in combination, to inhibit/remove undesirable bacteria from the food supply and to better manage their presence, populations, and/or survival during manufacture and storage of target foods/feed. The proposed research to find, characterize, and kill pathogens along the food chain continuum will expand our knowledge of the most prevalence/potent food borne pathogens and help us to elaborate better methods for controlling them in foods prior to human contact or consumption, thereby enhancing the safety of our global food supply. This new Project Plan was recently certified through the ARS Office of Scientific Quality Review (OSQR). For further details on current work see the 2016 annual report for project 8072-41420-015-00D.
Impacts
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Publications
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