Progress 01/06/11 to 01/05/16
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to determine the inactivation kinetics for foodborne pathogens suspended in foods treated using nonthermal process interventions (e.g., ionizing radiation and high pressure processing). 1. Determine gamma radiation D10 values of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga- toxin producing Escherichia coli (STEC). 2. Determine the effect of product temperature on the radiation resistance of foodborne pathogens suspended in ground meat and poultry products with emphasis on Shiga-toxin producing Escherichia coli (STEC). 3. Determine the high pressure processing inactivation kinetics of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga-toxin producing Escherichia coli (STEC). Approach (from AD-416): Non-O157 serovars of Shiga-toxin producing Escherichia coli (STEC) are now responsible for over 60% of STEC induced illnesses. The majority of illnesses caused by non-O157:H7 STEC have been due to serovars O26, O121, O103, O45, O111, and O145 which are now considered adulterants in beef and beef products by USDA Food Safety Inspection Service (FSIS). Currently, there are two non-thermal intervention technologies being used to inactivate foodborne pathogens internalized in ground meat and poultry products, viz., ionizing radiation (IR) and high pressure processing (HPP) . There is little data on the use of these technologies to inactivate these emerging STEC in food products. Recently, the use of IR for treatment of meat at non-refrigeration temperatures was approved by the FDA. There is little or no data available to describe inactivation kinetics for foodborne pathogens suspended in raw meat, which can now be irradiated at non-refrigeration temperatures. In addition, there is little information available regarding the association between genetic markers, attachment and aggregation, Shiga-toxin production, virulence factors, antibiotic resistance, etc. as relates to the ability of IR, HPP, or other intervention technologies to inactivate the STEC. The goal of this research is to improve development and validation of intervention technologies, in combination with metagenomics, to provide regulatory agencies the necessary information to complete new risk assessments for foodborne pathogens. We want to know if STEC virulence makes any difference when trying to kill them, and do regulatory agencies and industry need to make policy changes for use of intervention technologies? This project has focused on the use of nonthermal processing technologies with an emphasis on the inactivation of emerging nonO157:H7 Shiga toxin- producing Escherichia coli (STEC) in meat and poultry, with a component to investigate the role that virulence factors play in pathogen resistance to intervention technologies to aid in metagenomic risk assessments. STEC is responsible for approximately 176,000 illnesses, 3, 700 hospitalizations, and 30 deaths in the U.S. annually. These pathogenic bacteria are extremely diverse and more than 400 STEC serotypes have been isolated from human patients. Non-O157 STECs, serovars other than O157:H7, are now responsible for over 60% of STEC induced illnesses. The majority of non-O157:H7 STEC illnesses are now caused by the �big six� serotypes including O26, O45, O103, O111, O121, and O145. USDA Food Safety Inspection Service now requires testing of ground beef for the presence of the big six STEC. In recent years there has been a shift toward the big data approach to food safety and risk assessments that emphasize the role of genomics and bacterial genotype on how foodborne pathogens survive when exposed to different stresses, including how STEC survive exposure to food safety intervention technologies. Relatively few nonthermal food safety intervention technologies are available to inactivate foodborne pathogens internalized raw meat and poultry products. Those two technologies are limited to ionizing radiation (IR) and high pressure processing (HPP). Relatively little information is available on the ability of these technologies to inactivate STEC other than O157:H7 in ground beef. This project opened up a new area of science which we call �intervention genomics�. In the largest study of its kind the radiation resistance of 40 STEC (representing 12 serovars which carried various combinations of the shiga toxin 1 and 2 (stx1, stx2), intimin (eae), and enterohemolysin (ehx) virulence genes) suspended in refrigerated ground beef were determined. These STEC were human clinical isolates, from the environment, from animals and were generously provided by USDA Western Regional Research Center, Albany, California and USDA-ARS, Clay Center, Nebraska. The results we obtained when the individual isolates were suspended in 80% percent lean ground beef and exposed to HPP (4 C, 350 MPa, 0-30 min) or IR (4C, 0-1.8 kGy) were truly astonishing. For HPP the mean D10 was 9.74 min, with a range of 0.89 to 25.70 min, a > 25 fold difference between the HPP sensitive and resistant isolates. D10 is the processing condition that reduces the pathogen level by 90%. The mean HPP D10 of the STEC involved in human illness was 9.25 vs. 10.40 min for those not involved in human illness (p>0.05). The presence or absence of genes encoding virulence factors had no effect on the HPP D10. The IR the D10 ranged from 0.16 to 0.48 kGy, with a mean of 0.31 kGy for the 40 isolates. STEC associated with illness outbreaks had a mean IR D10 of 0.27 kGy, while nonoutbreak isolates had a mean D10 of 0.36 kGy which was significantly greater. The presence or absence of stx1, stx2, or both stx 1 and 2 had no affect on D10. The presence (0.30 kGy) or absence (0.35 kGy) of ehx had no affect on D10. However, the mean D10 of isolates lacking eae (0.37 kGy) were significantly higher than those containing eae (0.27 kGy). There was no difference in D10 for isolates lacking eae regardless of whether or not they were associated with a foodborne illness outbreak. There was no correlation between IR and HPP resistance or sensitivity indicating different mechanisms of resistance, and genetics, for stress response and survival to the two technologies. The consequences of these findings are significant. These are some of the first studies which look at HPP and IR inactivation of both the� big six� and O157:H7 STEC in ground beef. In addition, those studies which are published have used either single STEC isolates or a multi-isolate cocktail of STEC. Using the large data-set approach we determined the resistance of the STEC to HPP in ground beef has the potential to be much higher than previously reported, which includes a number of STEC which have been involved in human illness. A number of isolates had HPP D10 greater than 20 min. Meat and HPP processors will either need to change the HPP conditions needed to actually inactivate STEC in ground beef or develop new methods to improve the inactivation of STEC in ground beef such as including natural antimicrobial compounds to improve HPP inactivation. Meat and IR processors may need to make minor adjustments to inactivate STEC isolates such as the O104 serovars which cause illness in humans but lack the eae virulence factor. The results we obtained over the course of this project pose questions for other STEC associated research including: 1) what are the genetic differences between radiation and HPP resistant or sensitive isolates; 2) do these differences extend to resistance to other nonthermal intervention technologies; 3) are different detection methods needed for STEC isolates depending on the genotype and intervention technology used; and 4) will there be changes in policy away from the use of multi-isolate cocktails as recommended by regulatory agencies for validation of alternative food safety intervention technologies to the large data-set approach?
Impacts
(N/A)
Publications
- Rajkowski, K.T., Sommers, C.H. 2012. Effect of anolyte on background microflora, Salmonella and Listeria monocytogenes on catfish fillets. Journal of Food Protection. 75(4):765-770. DOI: 10.4315/0362-028X.JFP-11- 426.
- Sommers, C.H., Scullen, O.J., Sheen, S. 2016. Inactivation of uropathogenic Escherichia coli in ground chicken meat using high pressure processing and gamma radiation, and in purge and chicken meat surfaces by ultraviolet light. Frontiers in Microbiology. 7(413):1-6.
- Hsu, H., Sheen, S., Sites, J.E., Cassidy, J.M., Scullen, B.J., Sommers, C. H. 2014. Effect of high pressure impact on the survival of Shiga Toxin- producing Escherichia coli ('Big Six' and 0157) in ground beef. Food Microbiology. doi:10.1016/j.fm.2014.12.002.
- Hsu, H., Sheen, S., Sites, J.E., Huang, L., Wu, J. 2013. Effect of high pressure treatment on the survival of Shiga-Toxin producing Escherichia coli in strawberries. Food Microbiology. 40:25-30.
- Sheen, S., Cassidy, J.M., Scullen, O.J., Sommers, C.H. 2015. Inactivation of a diverse set of shiga toxin-producing Escherichia coli in ground beef by high pressure processing. Food Microbiology. 52:84-87.
- Sheen, S., Huang, L., Sommers, C.H. 2012. Survival of Listeria monocytogenes, E.coli 0157:H7 and Salmonella spp. on catfish fillets exposed to microwave heating in a continuous mode. Journal of Food Science. 77(8):E209-E214.
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Progress 10/01/14 to 09/30/15
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to determine the inactivation kinetics for foodborne pathogens suspended in foods treated using nonthermal process interventions (e.g., ionizing radiation and high pressure processing). 1. Determine gamma radiation D10 values of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga- toxin producing Escherichia coli (STEC). 2. Determine the effect of product temperature on the radiation resistance of foodborne pathogens suspended in ground meat and poultry products with emphasis on Shiga-toxin producing Escherichia coli (STEC). 3. Determine the high pressure processing inactivation kinetics of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga-toxin producing Escherichia coli (STEC). Approach (from AD-416): Non-O157 serovars of Shiga-toxin producing Escherichia coli (STEC) are now responsible for over 60% of STEC induced illnesses. The majority of illnesses caused by non-O157:H7 STEC have been due to serovars O26, O121, O103, O45, O111, and O145 which are now considered adulterants in beef and beef products by USDA Food Safety Inspection Service (FSIS). Currently, there are two non-thermal intervention technologies being used to inactivate foodborne pathogens internalized in ground meat and poultry products, viz., ionizing radiation (IR) and high pressure processing (HPP) . There is little data on the use of these technologies to inactivate these emerging STEC in food products. Recently, the use of IR for treatment of meat at non-refrigeration temperatures was approved by the FDA. There is little or no data available to describe inactivation kinetics for foodborne pathogens suspended in raw meat, which can now be irradiated at non-refrigeration temperatures. In addition, there is little information available regarding the association between genetic markers, attachment and aggregation, Shiga-toxin production, virulence factors, antibiotic resistance, etc. as relates to the ability of IR, HPP, or other intervention technologies to inactivate the STEC. The goal of this research is to improve development and validation of intervention technologies, in combination with metagenomics, to provide regulatory agencies the necessary information to complete new risk assessments for foodborne pathogens. We want to know if STEC virulence makes any difference when trying to kill them, and do regulatory agencies and industry need to make policy changes for use of intervention technologies? This project has focused on the use of nonthermal processing technologies with an emphasis on the inactivation of emerging nonO157:H7 Shiga toxin- producing Escherichia coli (STEC) in meat and poultry, with a component to investigate the role that virulence factors play in pathogen resistance to intervention technologies to aid in metagenomic risk assessments. STEC is responsible for approximately 176,000 illnesses, 3, 700 hospitalizations, and 30 deaths in the U.S. annually. These pathogenic bacteria are extremely diverse and more than 400 STEC serotypes have been isolated from human patients. Non-O157 STECs, serovars other than O157:H7, are now responsible for over 60% of STEC induced illnesses. The majority of non-O157:H7 STEC illnesses are now caused by the �big six� serotypes including O26, O45, O103, O111, O121, and O145. USDA Food Safety Inspection Service now requires testing of ground beef for the presence of the big six STEC. In recent years there has been a shift toward the big data approach to food safety and risk assessments that emphasize the role of genomics and bacterial genotype on how foodborne pathogens survive when exposed to different stresses, including how STEC survive exposure to food safety intervention technologies. Relatively few nonthermal food safety intervention technologies are available to inactivate foodborne pathogens internalized raw meat and poultry products. Those two technologies are limited to ionizing radiation (IR) and high pressure processing (HPP). Relatively little information is available on the ability of these technologies to inactivate STEC other than O157:H7 in ground beef. This project opened up a new area of science which we call �intervention genomics�. In the largest study of its kind the radiation resistance of 40 STEC (representing 12 serovars which carried various combinations of the shiga toxin 1 and 2 (stx1, stx2), intimin (eae), and enterohemolysin (ehx) virulence genes) suspended in refrigerated ground beef were determined. These STEC were human clinical isolates, from the environment, from animals and were generously provided by USDA Western Regional Research Center (Albany, California) and USDA-ARS, Clay Center (Nebraska). The results we obtained when the individual isolates were suspended in 80% percent lean ground beef and exposed to HPP (4 degrees C, 350 MPa, 0-30 min) or IR (4 degrees C, 0-1.8 kGy) were truly astonishing. For HPP the mean D10 was 9.74 min, with a range of 0.89 to 25.70 min, a > 25 fold difference between the HPP sensitive and resistant isolates. D10 is the processing condition that reduces the pathogen level by 90%. The mean HPP D10 of the STEC involved in human illness was 9.25 vs. 10.40 min for those not involved in human illness (p>0.05). The presence or absence of genes encoding virulence factors had no effect on the HPP D10. The IR the D10 ranged from 0.16 to 0.48 kGy, with a mean of 0.31 kGy for the 40 isolates. STEC associated with illness outbreaks had a mean IR D10 of 0. 27 kGy, while nonoutbreak isolates had a mean D10 of 0.36 kGy which was significantly greater. The presence or absence of stx1, stx2, or both stx 1 and 2 had no affect on D10. The presence (0.30 kGy) or absence (0. 35 kGy) of ehx had no affect on D10. However, the mean D10 of isolates lacking eae (0.37 kGy) were significantly higher than those containing eae (0.27 kGy). There was no difference in D10 for isolates lacking eae regardless of whether or not they were associated with a foodborne illness outbreak. There was no correlation between IR and HPP resistance or sensitivity indicating different mechanisms of resistance, and genetics, for stress response and survival to the two technologies. The consequences of these findings are significant. These are some of the first studies which look at HPP and IR inactivation of both the� big six� and O157:H7 STEC in ground beef. In addition, those studies which are published have used either single STEC isolates or a multi-isolate cocktail of STEC. Using the large data-set approach we have determined the resistance of the STEC to HPP in ground beef has the potential to be much higher than previously reported, which includes a number of STEC which have been involved in human illness. A number of isolates had HPP D10 greater than 20 min. Meat and HPP processors will either need to change the HPP conditions needed to actually inactivate STEC in ground beef or develop new methods to improve the inactivation of STEC in ground beef such as including natural antimicrobial compounds to improve HPP inactivation. Meat and IR processors may need to make minor adjustments to inactivate STEC isolates such as the O104 serovars which cause illness in humans but lack the eae gene. The results we have obtained pose questions for other STEC associated research including: 1) what are the genetic differences between radiation and HPP resistant or sensitive isolates; 2) do these differences extend to resistance to other nonthermal intervention technologies; 3) are different detection methods needed for STEC isolates depending on the genotype and intervention technology used; and 4) will there be changes in policy away from the use of multi-isolate cocktails as recommended by regulatory agencies for validation of alternative food safety intervention technologies to the large data-set approach? In other research we addressed the needs of the meat processing industry and USDA Food Safety Inspection Service by determining the inactivation kinetics for STEC in veal using high pressure processing and ultraviolet light UV-C). In those studies we determined that UV-C (1 J/cm2) killed 90% of STEC inoculated onto veal cutlet surfaces. When STEC were inoculated into veal drip (purge) which was then placed on food contact surfaces including stainless steel, high density polypropylene, and high density polyethylene a low UV-C dose of 125 mJ/cm2 killed 99.99% of the STEC. The HPP D10 (4 degrees C, 0-30 min) at 250, 350 or 450 MPa. The D10 was 19.3, 8.74, and 5.05 min, respectively. Both studies can be used by meat processors to provide safer veal products to consumers. Accomplishments 01 High Pressure Processing (HPP) database for inactivation of shiga toxin- producing Escherichia coli in ground beef. Shiga toxin-producing Escherichia coli (STEC) are common contaminants in ground beef and cause foodborne illness outbreaks. ARS researchers at Wyndmoor, Pennsylvania, determined the D10 value, the dose needed to kill 90% of a microorganism, for 40 STEC isolates which carried various combinations of genes necessary to cause illness in humans. The presence or absence of virulence factors (e.g. shiga toxin 1 or 2, intimin, or enterohemolysin) had no effect on the STEC HPP D-10. The D10 of the STEC ranged from 0.89 to 25.7 min at a pressure of 350 MPa. The results of this study will allow regulatory agencies and the food processing industry to conduct risk analysis and provide safer meat to consumers. Consumers, especially those who are immuno-compromised (e.g. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as the STEC. 02 The inactivation kinetics for Salmonella in ground chicken by high pressure processing (HPP) was determined. High pressure processing (HPP) is a green and sustainable non-thermal means to reduce harmful bacteria in foods. Salmonella contamination of poultry meat is a common foodborne illness risk for Americans. ARS researchers at Wyndmoor, Pennsylvania, found that at moderate operating conditions (e.g. 450MPa, 4 degrees C, 10 min), a five log reduction (100,000 cells per gram of food) of Salmonella spp. can be achieved in poultry meat (e.g. ground chicken). The results of this study will allow regulatory agencies and the food processing industry to conduct risk analysis and provide safer poultry meat to consumers. Consumers, especially those who are immuno- compromised (eg. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as Salmonella. 03 The inactivation kinetics for inactivation of shiga toxin-producing Escherichia coli in ground veal by high pressure processing (HPP) was determined. Shiga toxin-producing Escherichia coli (STEC) are common contaminants in veal. High Pressure Processing (HPP) is a green and sustainable nonthermal food safety intervention technology which can kill STEC inside ground veal. ARS researchers at Wyndmoor, Pennsylvania, determined the D10 value, the processing conditions needed to kill 90% (1 log) of STEC in ground veal. Ground veal was treated with HPP (4 degrees C, 0-30 min) at 250, 350 or 450 MPa. The D10 was 19.3, 8.74, and 5.05 min, respectively. This indicates the D10 for STEC in ground veal is similar to that for ground beef. Meat and HPP processors can use this information to provide safer veal to consumers. Consumers, especially those who are immuno-compromised (e.g. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as the STEC. 04 The ultraviolet light (UV-C) inactivation kinetics for shiga toxin- producing Escherichia coli in veal and veal purge were determined. Shiga toxin-producing Escherichia coli (STEC) are common contaminants in veal. Ultraviolet light (UV-C) is a safe and effective green and sustainable technology which can be used to kill bacteria on food and food contact surfaces. ARS researchers at Wyndmoor, Pennsylvania, found that UV-C (1 J/cm2) killed 90% of STEC inoculated onto veal cutlet surfaces. When STEC were inoculated into veal drip (purge) which was then placed on food contact surfaces including stainless steel, high density polypropylene, and high density polyethylene a low UV-C dose of 125 mJ/cm2 killed 99.99% of the STEC. Food processors and risk assessors will be able to provide safer veal to consumers. Consumers, especially those who are immuno-compromised (e.g. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as the STEC. 05 The inactivation kinetics for shiga toxin-producing Escherichia coli in ground beef by gamma radiation as effected by temperature were determined. Shiga toxin-producing Escherichia coli (STEC) are common contaminants in ground beef. Ionizing (gamma) irradiation is a safe and effective sustainable technology which can be used to kill bacteria in internalized in ground meat. The ability of gamma radiation to kill STEC in ground meat is effected by the meat temperature at the time of irradiation. ARS researchers at Wyndmoor, Pennsylvania, found that STEC in ground beef had D10, the radiation dose needed to kill 90% of the STEC, of 0.37, 0.27, 0.24, and 0.24 kGy at -20, -12, 12, and 20 degrees C, respectively, and a predictive equation was developed to describe the relationship between meat temperature and D10. Food processors and risk assessors will be able to provide safer ground beef to consumers. Consumers, especially those who are immuno-compromised (e.g. cancer patients, diabetics, and the HIV/AIDS population) will benefit from having more information about foods treated with alternative processes which kill harmful bacteria such as the STEC.
Impacts
(N/A)
Publications
- Zhou, S., Sheen, S., Pang, Y., Liu, L.S., Yam, K.L. 2015. Modeling the impact of vapor thymol concentration, temperature and modified atmosphere condition on growth behavior of Salmonella spp. on raw shrimp. Journal of Food Protection. 78(2):293-301.
- Sommers, C.H., Rajkowski, K.T., Scullen, O.J., Cassidy, J.M., Fratamico, P. M., Sheen, S. 2015. Inactivation of shiga toxin-producing Escherichia coli in lean ground beef by gamma irradiation. Food Microbiology. DOI: 10.1016/ j.fm.2015.02/013.
- Sheen, S., Cassidy, J.M., Scullen, O.J., Uknalis, J., Sommers, C.H. 2015. Inactivation of Salmonella spp. in ground chicken using High Pressure Processing. Food Control. 57:41-47.
- Sommers, C.H., Sheen, S. 2015. Inactivation of avirulent Yersinia pestis on food and food contact surfaces by ultraviolet light and freezing. Food Microbiology. DOI: 10.1016/j.fm.2015.02.008.
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to determine the inactivation kinetics for foodborne pathogens suspended in foods treated using nonthermal process interventions (e.g., ionizing radiation and high pressure processing). 1. Determine gamma radiation D10 values of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga- toxin producing Escherichia coli (STEC). 2. Determine the effect of product temperature on the radiation resistance of foodborne pathogens suspended in ground meat and poultry products with emphasis on Shiga-toxin producing Escherichia coli (STEC). 3. Determine the high pressure processing inactivation kinetics of foodborne pathogens in ground meat and poultry with emphasis on a genetically-diverse set of Shiga-toxin producing Escherichia coli (STEC). Approach (from AD-416): Non-O157 serovars of Shiga-toxin producing Escherichia coli (STEC) are now responsible for over 60% of STEC induced illnesses. The majority of illnesses caused by non-O157:H7 STEC have been due to serovars O26, O121, O103, O45, O111, and O145 which are now considered adulterants in beef and beef products by USDA Food Safety Inspection Service (FSIS). Currently, there are two non-thermal intervention technologies being used to inactivate foodborne pathogens internalized in ground meat and poultry products, viz., ionizing radiation (IR) and high pressure processing (HPP) . There is little data on the use of these technologies to inactivate these emerging STEC in food products. Recently, the use of IR for treatment of meat at non-refrigeration temperatures was approved by the FDA. There is little or no data available to describe inactivation kinetics for foodborne pathogens suspended in raw meat, which can now be irradiated at non-refrigeration temperatures. In addition, there is little information available regarding the association between genetic markers, attachment and aggregation, Shiga-toxin production, virulence factors, antibiotic resistance, etc. as relates to the ability of IR, HPP, or other intervention technologies to inactivate the STEC. The goal of this research is to improve development and validation of intervention technologies, in combination with metagenomics, to provide regulatory agencies the necessary information to complete new risk assessments for foodborne pathogens. We want to know if STEC virulence makes any difference when trying to kill them, and do regulatory agencies and industry need to make policy changes for use of intervention technologies? This is a new bridge project approved in January 2014 which was redirected from catfish safety (project completed) towards the use of intervention technologies to improve the safety of meat and poultry products. The project focuses on nonthermal processing technologies with an emphasis towards inactivation of emerging non-O157:H7 Shiga Toxin- producing Escherichia coli (STEC) in meat and poultry, with a component to investigate the role that virulence factors play in pathogen resistance to intervention technologies to aid in metagenomic risk assessments. Foodborne pathogens are responsible for approximately 48 million cases of illness, 128,000 hospitalizations, and 3000 deaths each year in the US at an estimated healthcare cost of $152 billion annually. One group of foodborne pathogens, Shiga toxin-producing Escherichia coli (STEC), is responsible for approximately 176,000 illnesses, 3,700 hospitalizations, and 30 deaths in the US annually. These pathogenic bacteria are extremely diverse and more than 400 STEC serotypes have been isolated from human patients. Non-O157 STECs, serovars other than O157:H7, are now responsible for over 60% of STEC-induced illnesses. Moreover, FoodNet data from 2000-2009 indicate that, while illnesses caused by E. coli 0157:H7 are decreasing, illnesses from other STEC are increasing. The majority of non-O157:H7 STEC illnesses are caused by the �big six� serotypes including O26, O45, O103, O111, O121, and O145. USDA FSIS now requires testing of ground beef for the presence of the big six STEC. In addition to the big six, other serogroups involved in foodborne illness outbreaks include O104 which has been associated with serious illness outbreaks in Europe and the US. Relatively few nonthermal technologies are available to inactivate foodborne pathogens in packaged raw meat and poultry products. Those two technologies are limited to ionizing radiation (IR) and high pressure processing (HPP) because of their ability to inactivate microorganisms internalized within the food matrix. Research comparing the IR resistance of non-O157:H7 �big six� vs. O157:H7 STEC suspended in frozen ground beef and veal, ground venison and elk, ground turkey and chicken, and catfish and shrimp and it was determined the radiation dose needed to inactivate O157:H7 would also control the �big six� STEC that we used in the study. In the largest study of its kind the radiation resistance of 40 STEC (representing 12 serotypes which carried various combinations of the shiga toxin 1 and 2, intimin, and enterohemolysin virulence factors) suspended in refrigerated ground beef were determined. We observed that STEC which lacked the intimin gene (eg. the LEE-Pathogenicity Island) were typically more resistant to ionizing radiation than the other E. coli, and that the highly virulent O104 were more resistant to IR (ca. D10= 0.4 kGy) than the O157:H7 that we tested. In initial experiments using comparing the resistance of the non-O157:H7 STEC versus O157:H7 suspended in ground beef we found that a HPP treatment of 450 MPa/5-7oC/15 min inactivated >5 log of both the �big six� and O157:H7 STEC. A similar study was conducted using strawberry puree. Research to compare the HPP resistance of the same 40 STEC used in the IR study is nearing completion. These important results were transferred to the USDA FSIS, the meat processing industry, and the HPP and radiation processing industries and will allow risk assessors and the food processing industry to supply safer meat products to consumers. Significant Activities that Support Special Target Populations: This research provides immune-compromised populations such as cancer patients, diabetics, and HIV/AIDS with valuable information concerning safer food products available for their consumption, as is specifically noted by the Centers for Disease Control and Prevention. Accomplishments 01 Inactivation of Shiga Toxin-producing Escherichia coli in strawberry puree by high pressure processing. Strawberries have been implicated in a foodborne illness outbreaks caused by contamination with Shiga Toxin- producing Escherichia coli (STEC). High pressure processing (HPP) is a commercialized green and sustainable technology which does not require the use of chemical additives to kill bacteria in foods. In research conducted by ARS researchers at Wyndmoor, Pennsylvania in cooperation with scientists from National Taiwan University compared the ability of HPP to kill both E. coli O157:H7 and non-O157:H7 STEC types (referred to as the �big six�) in strawberry puree was examined. HPP treatment at 350 MPa for 5 min significantly reduced all the STEC by >99.999% (>5 log). These results show that HPP can inactivate both O157:H7 and the non-O157:H7 STEC to similar levels. This research provides valuable information to both regulatory agencies and the food processing industry with valuable information for risk assessments and allows them to provide safer ground beef to consumers. This research provides immune-compromised populations such as cancer patients, diabetics, and HIV/AIDS with valuable information concerning safer food products available for their consumption. 02 Inactivation of Shiga Toxin-producing Escherichia coli in ground beef by high pressure processing. Ground beef has been implicated in a foodborne illness outbreaks caused by contamination with Shiga Toxin- producing Escherichia coli (STEC). High Pressure Processing (HPP) is a commercialized green and sustainable technology which does not require the use of chemical additives to kill bacteria in foods. In research conducted by ARS researchers at Wyndmoor, Pennsylvania in cooperation with scientists from National Taiwan University compared the ability of HPP to kill both E. coli O157:H7 and non-O157:H7 STEC types (referred to as the �big six�) in ground beef was examined. HPP treatment at 450 MPa/15 min/5-7 oC significantly reduced all the STEC by >99.999% (>5 log). These results show that HPP can inactivate both O157:H7 and the non-O157:H7 STEC to similar levels. This research provides valuable information to both regulatory agencies and the food processing industry with valuable information for risk assessments and allows them to provide safer ground beef to consumers. This research provides immune-compromised populations such as cancer patients, diabetics, and HIV/AIDS with valuable information concerning safer food products available for their consumption. 03 Inactivation of Shiga Toxin-producing Escherichia coli in frozen foods by ionizing radiation. Many foods have been implicated in a foodborne illness outbreaks caused by contamination with Shiga Toxin-producing Escherichia coli (STEC). Ionizing radiation (IR) is a commercialized green and sustainable technology which does not require the use of chemical additives to kill bacteria in foods. ARS researchers at Wyndmoor, Pennsylvania compared the ability of IR to kill non-O157:H7 STEC types (referred to as the �big six�) in frozen foods (beef, veal, venison, elk, chicken, turkey, catfish, peas, corn). An IR dose of 2.5 kGy reduced the big six STEC by ca. 99.999% (5 log). This research provides valuable information to both regulatory agencies and the food processing industry with valuable information for risk assessments and allows them to provide safer ground beef to consumers. This research provides immune-compromised populations such as cancer patients, diabetics, and HIV/AIDS with valuable information concerning safer food products available for their consumption. 04 Inactivation of Shiga Toxin-producing Escherichia coli in refrigerated ground beef by ionizing radiation. Ground beef has been implicated in a foodborne illness outbreaks caused by contamination with Shiga Toxin- producing Escherichia coli (STEC). Ionizing radiation (IR) is a commercialized green and sustainable technology which does not require the use of chemical additives to kill bacteria in foods. ARS researchers at Wyndmoor, Pennsylvania compared the ability of IR to kill 40 different STEC isolates categorized by the types of virulence genes they contained. We found that a specific type of STEC, which lacks the intimin virulence gene, and includes the highly virulent O104 serogroup, was slightly more radiation resistant than E. coli O157 we have tested. A radiation dose of 2.0 kGy will easily provide a 99.999% reduction of O104 STEC in refrigerated ground beef. This research provides valuable information to both regulatory agencies and the food processing industry with valuable information for risk assessments and allows them to provide safer ground beef to consumers. This research provides immune-compromised populations such as cancer patients, diabetics, and HIV/AIDS with valuable information concerning safer food products available for their consumption.
Impacts
(N/A)
Publications
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Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to enhance seafood safety, with special emphasis on catfish, through the development of new technologies and new original scientific information. The specific objectives are as follows: 1. Develop and validate models to simulate pathogen behavior under both growth and inactivation conditions. 2. Develop and validate non-thermal and advanced thermal intervention technologies to inactivate pathogens and spoilage microorganisms in raw and ready-to-eat seafood and aquaculture products, in particular, catfish. 3. Define the impact of non-thermal and advanced thermal intervention technologies on food quality and chemistry. It is expected that Objective 1 will contribute to the overall goal of this project through the development of new robust foodborne pathogen growth models that will aid regulatory agencies in their risk assessments and science-based policy decisions. Objectives 2 and 3 will contribute through the development of intervention technologies, which at the same time will enhance, or at the minimum, preserve the original product quality. Approach (from AD-416): The incidence of foodborne illness associated with the consumption of contaminated seafood is disproportionately high. This project constitutes a comprehensive research effort to enhance seafood safety, with special emphasis on catfish. This will be accomplished through: 1) developing robust foodborne pathogen growth models to aid risk assessors in regulatory agencies in science-based policy decisions, 2) developing effective intervention technologies, and 3) enhance or, at the minimum, preserve seafood-quality. Intervention technologies to be investigated include flash pasteurization, pulsed and ultraviolet light, and ionizing (gamma) irradiation, electrolyzed water, modified atmosphere packaging, and GRAS food additives, etc. These interventions will be combined to obtain incremental improvements in microbial inactivation, the so-called hurdle to maximize foodborne pathogen inactivation. Food quality evaluation, studies will be conducted on the seafood subjected to various intervention methods to identify those technologies, which in addition to being effective in inactivating pathogens, are simultaneously neutral or even improve product quality. Seafood is responsible for more cases of foodborne illness when adjusted for per capita consumption than beef, poultry, or produce. A study to determine the incidence of heavy metals, banned antibiotics, and foodborne pathogens in catfish nuggets sold in the northeast United States was completed by researchers at Wyndmoor, PA in cooperation with scientists at Delaware State University and Cheyney University. This research is now in press in the Journal of Food Processing and Technology as part of a catfish special edition. In cooperative research between ARS researchers in Wyndmoor, PA and Mississippi State University the growth of foodborne pathogens in seafood including non-O157: H7 shigatoxin producing Escherichia coli (non-O157:H7 STECs) in catfish fillet meat at refrigeration and abuse temperatures (5, 10, 15, 22 and 30 degrees C) was evaluated. A predictive model was developed to describe the growth of non-O157:H7 STECs in catfish fillet meat. In addition, the thermal inactivation kinetics (thermal d and z-values) for the non non- O157:H7 STECs suspended in catfish fillet meat were determined. Radiation (gamma) inactivation kinetics for six non-O157:H7 serovars, as well as three O157:H7 isolates, propagated under acid resistant and tolerant conditions were determined. The results showed that radiation doses needed to inactivate E. coli O157:H7 could also inactivate non-O157:H7 serovars. This completed research fills a gap in the field of thermal and non-thermal processing as well as predictive microbiology. In cooperative research with scientists from the Residue Chemistry and Predictive Microbiology Research Unit in Wyndmoor, PA the use of flash (steam) pasteurization in combination with edible antimicrobial films was evaluated for inactivation of Listeria spp. Flash pasteurization along with edible films were able to inactivate 99.99% of Listeria on shrimp (Objective 2). Researchers at Wyndmoor, PA, in collaboration with scientists at Edinboro Universty of Pennsylvania determined the effect of ionizing radiation on lipid oxidation, color, mutagenicity, and clastogenicity of frozen crawfish tail meat. Ionizing (gamma) radiation had no effect on frozen crawfish tail meat chemistry or quality. This will help the US FDA evaluate a petition to allow irradiation of crustaceans in the United States. Accomplishments 01 Growth modeling of non-O157:H7 shiga-toxin producing Escherichia coli in catfish fillet meat. Due to contamination of water in much of the world, it is not unusual for finfish to be contaminated with foodborne pathogens, including non-O157:H7 shiga-toxin producing Escherichia coli (non-O157 STEC), and consumption of those contaminated fish cause foodborne illness in many countries. Fish may be stored at refrigeration or ambient temperatures prior to preparation and consumption. In this study, ARS researchers at Wyndmoor, Pennsylvania in cooperation with researchers at Mississippi State University determined the growth potential of a multi-isolate cocktail of non- O157:H7 serovars in catfish fillet meat at various storage temperatures. There was no STEC growth at 4 degrees C. However, the STECs were able to grow at 10, 15, 20 and 30 degrees C in a temperature dependent manner, with higher growth rate associated with higher temperature. Growth curves constructed using ComBase DMfit provided a good statistical fit to the observed data, resulting in a high correlation coefficient. The results of this study provide information to risk assessors regarding the growth potential of the STECs on seafood using catfish as a model system. The growth potentials of Salmonella spp. on raw tuna meat at different temperatures (including abuse temperature at 8-22 degrees C) also were established using similar methodology mentioned above. These data may enhance the safety of raw fish consumption. 02 Gamma radiation inactivation of O157:H7 and non-O157:H7 shigatoxin producing Escherichia coli in foods. Shigatoxin producing Escherichia coli (STEC) cause foodborne illnesses on a worldwide basis through contamination of many food types. Ionizing (gamma) radiation is a technology which is used on a global basis to improve the safety and shelf-life of foods. In this study the ability of gamma radiation to inactivate non-O157:H7 serovars and O15:H7 serovars suspended in catfish fillet meat at refrigeration temperature (4 degrees C) were compared by ARS researchers at Wyndmoor, Pennsylvania. The radiation doses needed to inactivate the non-O157:H7 STECs were similar to those needed to inactivate O157:H7. The results of this study provide information to risk assessors regarding the radiation doses needed to inactivate a wide variety of STEC serovars in seafood. 03 Irradiation of crustaceans. Seafood, when adjusted for per capita consumption, caused more foodborne illness outbreaks than meat, poultry, or produce. Ionizing (gamma) radiation is a technology which is used on a global basis to improve the safety and shelf-life of foods. In a study conducted by ARS researchers at Wyndmoor, Pennsylvania in cooperation with scientists at Edinboro University of Pennsylvania crawfish tail meat and raw shrimp were individually quick frozen and then gamma irradiated to a dose of 10 kGy. The color, fat rancidity, and the ability of irradiated crawfish and shrimp meat to damage DNA in human and bacterial cells was examined. Gamma radiation had no effect on the quality of crawfish tail or shrimp meat. No adverse effects in bacterial or human cells were observed. This research will help the US FDA evaluate a petition to allow irradiation of crustaceans in the United States.
Impacts
(N/A)
Publications
- Pang, Y., Sheen, S., Zhou, S., Liu, L.S., Yam, K. 2013. Antimicrobial effect of allyl isothiocyanate and modified atmosphere on Pseudomonas aeruginosa in fresh catfish fillet under abuse temperatures. Journal of Food Science. Volume 78(4)M555-M559.
- Khosravi, P., Silva, J., Sommers, C.H., Sheen, S. 2013. Thermal inactivation of non-0157:H7 Shigatoxin producing Escherichia coli(STEC) on catfish fillets. Journal of Food Processing and Technology.
- Sommers, C.H., Scullen, B.J., Paoli, G., Bhaduri, S. 2012. Inactivation of F.tularensis Utah-112 on food and food contact surfaces by ultraviolet light. Journal of Food Processing and Technology. doi:10.4172/2157-7110. S11-002.
- Zhou, S., Sheen, S., Liu, L.S., Pang, Y., Yam, K.L. 2013. Antimicrobial effects of vapor phase thymol, modified atmosphere and their combination against Salmonella spp. on raw shrimp. Journal of Food Science. Volume 78(5):M725-M730.
- Khosravi, P., Silva, J., Sommers, C.H., Sheen, S. 2013. Growth of non- 0157:H7 shiga-toxin producing Escherichia coli on catfish fillets. Journal of Food Processing and Technology.
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): The overall goal of this project is to enhance seafood safety, with special emphasis on catfish, through the development of new technologies and new original scientific information. The specific objectives are as follows: 1. Develop and validate models to simulate pathogen behavior under both growth and inactivation conditions. 2. Develop and validate non-thermal and advanced thermal intervention technologies to inactivate pathogens and spoilage microorganisms in raw and ready-to-eat seafood and aquaculture products, in particular, catfish. 3. Define the impact of non-thermal and advanced thermal intervention technologies on food quality and chemistry. It is expected that Objective 1 will contribute to the overall goal of this project through the development of new robust foodborne pathogen growth models that will aid regulatory agencies in their risk assessments and science-based policy decisions. Objectives 2 and 3 will contribute through the development of intervention technologies, which at the same time will enhance, or at the minimum, preserve the original product quality. Approach (from AD-416): The incidence of foodborne illness associated with the consumption of contaminated seafood is disproportionately high. This project constitutes a comprehensive research effort to enhance seafood safety, with special emphasis on catfish. This will be accomplished through: 1) developing robust foodborne pathogen growth models to aid risk assessors in regulatory agencies in science-based policy decisions, 2) developing effective intervention technologies, and 3) enhance or, at the minimum, preserve seafood-quality. Intervention technologies to be investigated include flash pasteurization, pulsed and ultraviolet light, and ionizing (gamma) irradiation, electrolyzed water, modified atmosphere packaging, and GRAS food additives, etc. These interventions will be combined to obtain incremental improvements in microbial inactivation, the so-called hurdle to maximize foodborne pathogen inactivation. Food quality evaluation, studies will be conducted on the seafood subjected to various intervention methods to identify those technologies, which in addition to being effective in inactivating pathogens, are simultaneously neutral or even improve product quality. Seafood is responsible for more cases of foodborne illness when adjusted for per capita consumption than beef, poultry, or produce. Initial research focused on assessment of spoilage bacteria, the incidence and prevalence of Salmonella spp., and the heavy metal and banned veterinary drug residues on retail catfish fillets sold in the north east United States in cooperation with Delaware State University and Cheyney University as part of research funded by USDA Food Safety Inspection Service. All project deliverables met, and the results were transferred to FSIS. In cooperative research between ARS researchers in Wyndmoor, PA and Mississippi State University the growth of foodborne pathogens in seafood including Salmonella in yellow fin tuna and non-O157: H7 shigatoxin producing Escherichia coli in catfish at refrigeration and abuse temperatures (5, 10, 15, 22 and 30 degrees C) was evaluated (Objective 1). This completed research fills a gap in the field of predictive microbiology since models which predict the growth and allow the assessment of risks associated with consumption of contaminated seafood. In other research a new microwave system with automatic feedback control to provide more even heating of fish fillets was used, in combination with a phosphate solution, to improve the quality of microwave cooked seafood. The new approach to microwave cooking produced catfish fillets with improved quality while inactivating 99.999% of the foodborne pathogens Listeria monocytogenes, Salmonella, and Escherichia coli. Significant progress (Objective 2 and 3) has been made in developing and validating ultraviolet light (UV-C) for decontamination of seafood and food contact surfaces (Objective 2 and 3). ARS researchers in Wyndmoor, PA demonstrated the ability of a commercial UV-C conveyor to inactivate 90-150% of the foodborne pathogen surrogate F. tularensis Utah- 112 on catfish and tilapia fillets and >99.99% inactivation of the microorganism suspended in fish exudates on stainless steel and plastic food contact surfaces. In new developments research collaborations have been initiated with scientists from the U.S. Food and Drug Administration to develop and validate nonthermal processing technologies for inactivation of histamine producing bacteria on seafood. Research collaborations have also been initiated with a large east coast seafood processor and distributor to assess the effectiveness of nonthermal interventions in an actual commercial processing environment. Significant Activities that Support Special Target Populations: Research on the use of nonthermal and thermal process interventions targets the needs of the seafood industry and populations of people who are at risk of infection, such as those who have underlying diseases such as diabetes and weakened immune systems. Seafood products also have a relatively short-shelf life. Research targets small catfish processors which have been negatively impacted by the increasing volume of imported product. Accomplishments 01 Predictive microbiology for the growth of foodborne pathogens on seafood When adjusted for per capita consumption, seafood is associated with foo borne illness more than beef, poultry, or produce. Little or no models exist to predict foodborne pathogen growth in seafood. ARS researchers a Wyndmoor, Pennsylvania, in cooperation with researchers at Mississippi State University, assessed the growth potential of spoilage microorganis and foodborne pathogens on seafood including catfish fillets and yellow fin tuna. Growth curves at 5, 10, 15, 22 and 30 degrees C were completed for non-O157:H7 shigatoxin producing Escherichia coli inoculated onto catfish and Salmonella inoculated onto yellow fin tuna. This research fills a much needed gap in the field of predictive microbiology and will assist seafood processors and regulatory agencies assess risks associate with consumption of both properly refrigerated and temperature abused seafood which has become contaminated with foodborne pathogens. 02 Microwave cooking impact on pathogen inactivation on catfish fillets. When adjusted for per capita consumption, seafood is associated with foo borne illness more than beef, poultry, or produce. Microwave cooking is used extensively at consumer, wholesale and retail levels, which can include the cooking of seafood. However, microwave cooking can be uneven resulting in cold spots, and allow the survival of foodborne pathogens. ARS researchers at Wyndmoor, Pennsylvania designed a microwave oven (125 watts) which used automatic feedback (80-90 degrees C/ 2 min) and a specially formulated phosphate solution to enhance even cooking of catfi fillets. The Food and Drug Administration recommendation for a 5 log (99 999%) reduction of foodborne pathogens including L. monocytogenes, Salmonella, and E. coli O157:H7 were attained, without damage to the quality of the fish fillets normally attributed to microwave cooking. These results will help the microwave and food service industries provid safer microwave cooked seafood products to consumers. 03 Inactivation of Francisella tularensis Utah-112 in fish and fish exudate using ultraviolet light. When adjusted for per capita consumption, seafo is associated with food borne illness more than beef, poultry, or produc In this study, ARS researchers at Wyndmoor, Pennsylvania used ultraviole light (UV-C, 254 nm) to inactivate the avirulent foodborne pathogen surrogate F. tularensis Utah-112 on catfish and tilapia fillets and thei exudates inoculated onto food contact surfaces. When Utah-112 was suspended in catfish and tilapia exudates and placed on stainless steel and plastic food contact surfaces, which were then passed through a commercial UV-C conveyor, 0.5 J/cm2 inactivated >99.99% of the microorganism. UV-C (1 J/cm2) inactivated 90 and 150% of Utah-112 inoculated on catfish and tilapia fillets, respectively. UV-C had no negative impact on fish fillet quality. This study demonstrates the effectiveness of UV-C for decontamination of fish and food contact surfaces using actual commercial equipment. This will assist seafood processors provide safer products to consumers. 04 Seafood, when adjusted for per capita consumption, is associated with foodborne illness more than meat, poultry, or produce. In research conducted by ARS researchers at Wyndmoor, Pennsylvania, catfish fillets were rinsed with near-neutral electrolyzed water (anaolyte) having a pH 6.0-6.5 and an oxidation reduction potential greater than 700 mV. Catfis fillets which were inoculated with Salmonella were treated with anolyte with a residual chlorine level of 300 ppm for 3 minutes. The treatment reduced Salmonella levels by 90%. In addition, Salmonella levels did not increase when the catfish fillets were held for 8 days at refrigeration (4C) temperature. The treatment with anolyte had no negative effect on catfish fillet quality. This method can be used by seafood processors to provide safer fish fillets to consumers.
Impacts
(N/A)
Publications
- Sommers, C.H., Rajkowski, K.T., Sheen, S., Samer, C., Bender, E. 2011. The effect of cryogenic freezing and gamma irradiation on the survival of Salmonella on frozen shrimp. Journal of Food Processing and Technology. DOI: 10.4172/2157-7110 S8-001.
- Sommers, C.H., Mackay, W., Geveke, D.J., Lemmenes, B., Pulsfus, S. 2012. Inactivation of Listeria innocua on frankfurters using flash pasteurization and lauric arginate ester. Journal of Food Processing and Technology. 3(3):1000147.
- Rajkowski, K.T. 2012. Thermal inactivation of Escherichia coli O157:H7 and Salmonella on catfish and tilapia. Food Microbiology. 30(2)427-431.
- Rajkowski, K.T., Sommers, C.H. 2012. Effect of trisodium phosphate or water dip on the survival of Salmonella and Listeria monocytogenes inoculated catfish before and after freezing. Journal of Aquatic Food Product Technology. 21(1):39-47.
- Sheen, S., Hwang, C., Juneja, V.K. 2012. Impact of chlorine, termperature and freezing shock on the growth behavior of Escherichia coli 0157:H7 on ready to eat meats. Food and Nutrition Sciences. DOI: 10.4236/fns.2012. 34075.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The overall goal of this project is to enhance seafood safety, with special emphasis on catfish, through the development of new technologies and new original scientific information. The specific objectives are as follows: 1. Develop and validate models to simulate pathogen behavior under both growth and inactivation conditions. 2. Develop and validate non-thermal and advanced thermal intervention technologies to inactivate pathogens and spoilage microorganisms in raw and ready-to-eat seafood and aquaculture products, in particular, catfish. 3. Define the impact of non-thermal and advanced thermal intervention technologies on food quality and chemistry. It is expected that Objective 1 will contribute to the overall goal of this project through the development of new robust foodborne pathogen growth models that will aid regulatory agencies in their risk assessments and science-based policy decisions. Objectives 2 and 3 will contribute through the development of intervention technologies, which at the same time will enhance, or at the minimum, preserve the original product quality. Approach (from AD-416) The incidence of foodborne illness associated with the consumption of contaminated seafood is disproportionately high. This project constitutes a comprehensive research effort to enhance seafood safety, with special emphasis on catfish. This will be accomplished through: 1) developing robust foodborne pathogen growth models to aid risk assessors in regulatory agencies in science-based policy decisions, 2) developing effective intervention technologies, and 3) enhance or, at the minimum, preserve seafood-quality. Intervention technologies to be investigated include flash pasteurization, pulsed and ultraviolet light, and ionizing (gamma) irradiation, electrolyzed water, modified atmosphere packaging, and GRAS food additives, etc. These interventions will be combined to obtain incremental improvements in microbial inactivation, the so-called hurdle to maximize foodborne pathogen inactivation. Food quality evaluation, studies will be conducted on the seafood subjected to various intervention methods to identify those technologies, which in addition to being effective in inactivating pathogens, are simultaneously neutral or even improve product quality. This project has just recently been approved by OSQR. Research towards meeting the project�s first year milestones has been initiated in order to address NP108 Food Safety Goals (Components 1D - Pathogen Toxins and Chemical Contaminants � Intervention Strategies, 2D � Pathogen Toxins and Chemical Contaminants � Processing Intervention Strategies). As part of the research continued from 1935-42000-054-00D, research conducted with worked with two 1890s institutions (Delaware State University and Cheyney University) and USDA FSIS to determine the microbiological quality and incidence of chemical contaminants of retail catfish in the northeast U.S. has continued and the results to date have been reported to USDA FSIS. The use of process interventions to control foodborne pathogens and spoilage bacteria on whole catfish immediately prior to processing using electrolyzed water anolyte, ultraviolet light, and flash pasteurization has been initiated, with the catfish being obtained from the USDA-ARS Catfish Genetics Laboratory in Mississippi. Research on the use of cryogenic freezing, electrolyzed water anolyte, ultraviolet light, microwaves, and GRAS antimicrobials for control of foodborne pathogens on catfish fillets has been initiated. Growth studies required for development of models to predict pathogen behavior on catfish fillets have been initiated. In other research, preliminary studies were conducted to determine the precedence of foodborne pathogens including Salmonella spp., Staphylococcus aureus, Escherichia coli O157:H7, Listeria monocytogenes, and Vibrio spp. in raw frozen shrimp has been initiated. To date approximately 75% of the samples processed have tested positive for pathogenic vibrio species and approximately 10% have tested positive for Listeria monocytogenes. This has resulted in the initiation of research on the use of intervention technologies including cryogenic freezing, electrolyzed water anolyte, flash pasteurization, ultraviolet light to control foodborne pathogens in crustaceans. We expect to fully meet the required first-year milestones listed for completion in FY2012. Accomplishments 01 Inactivation of foodborne pathogens on crawfish meat by cryogenic freezi and gamma radiation. Seafood, including crawfish meat, is occasionally associated with foodborne illness outbreaks in the U.S. In order to provide a solution to this problem, and assist the U.S. Food and Drug Administration (FDA) evaluate a petition to allow treatment of crustacea with ionizing radiation to control foodborne pathogens, the radiation D- values (the radiation dose needed to inactivate 90% of a foodborne pathogen) were determined on frozen crawfish meat by ARS researchers at Wyndmoor, PA. Because the majority of seafood sold in the U.S. is sold frozen, or frozen and then thawed prior to sale, the effect of freezing foodborne pathogen survival was determined using a pilot scale commercia cryogenic freezer. Cryogenic freezing (-85 deg C, 3 min) inactivated ove 70% of Salmonella spp., Vibrio spp., and Escherichia coli O157:H7 that w inoculated onto crawfish meat. Cryogenic freezing had no effect on the survival of Listeria monocytogenes and Staphylococcus aureus. The radiation D-10 values were 0.81, 0.58, 0.50, 0.49, and 0.36 kGy for L. monocytogenes, S. aureus, Vibrio spp., and E. coli O157:H7, respectively This study met the goal of providing crawfish processors new pathogen inactivation values that can be attributed to cryogenic freezing, which can be included as part of their Hazard Analysis and Critical Control Point Plans. In addition, this research met the goal of providing the FD with radiation D-10 values needed to evaluate the petition to allow irradiation of crustaceans (including crawfish) in the U.S. 02 Decontamination of whole fish by flash pasteurization. Seafood is occasionally associated with foodborne illness outbreaks in the U.S. Research by ARS researchers at Wyndmoor, PA, demonstrated that decontamination of catfish surfaces by flash pasteurization immediately prior to processing reduces microflora that can be transferred to finish fillets, and thus extend the fillet shelf-life. Flash pasteurization, a process that uses short bursts of steam to inactivate microorganisms on food product surfaces, and has minimal impact on product quality, was us to decontaminate whole catfish surfaces. Flash pasteurization (2 seconds steam, 115 deg C) inactivated >90% of mesophilic bacteria and >99% of psychrotrophic bacteria on catfish surfaces. Similar results were obtain using whole butterfish, black porgy, and white perch. The results of thi research will allow seafood processors to decontaminate fish surfaces immediately prior to processing, allowing them to make safer fish fillet with extended shelf-life.
Impacts
(N/A)
Publications
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