Progress 02/10/11 to 02/09/16
Outputs
Progress Report Objectives (from AD-416): To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416): An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/ g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh-cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf- life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re-growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. The goal of this project was to develop treatments and technologies to reduce the risk of pathogen contamination and maintain the sensory and nutritional quality of ready-to-eat foods through an integrated approach of processing and packaging technologies. Chemical and physical intervention technologies such as ultraviolet-C, pulsed electric field, novel antimicrobial combinations, high pressure processing, natural antimicrobial compounds and gaseous treatments were developed/modified/ optimized to maximize their effectiveness in inactivating common foodborne pathogens. The impact of the chemical and physical intervention technologies on sensory properties, nutrients, and shelf-life were also evaluated. Furthermore, formation of chemical by-products such as trichloromethane and furan as a result of chemical and physical interventions was investigated. A number of antimicrobial packaging systems were developed to reduce pathogens during storage and display. Finally, combinations of various intervention technologies were evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Several treatments and combinations were able to achieve more than 99.9% reductions of human pathogens. A number of collaborative research agreements has been established with industry during the project cycle. Accomplishments 01 Food containers with antimicrobial surface. Containers are used for fruits and vegetables in the field and storage, on display in stores and during transportation. Food containers are easily contaminated with foodborne pathogens. When a contaminated container is in contact with food, pathogens would transfer from the container to the food, resulting in cross contamination. Therefore, it is important to have a pathogen-free container. ARS researchers in Wyndmoor, Pennsylvania developed methods and coating formulas to produce food containers with antimicrobial surface. Specifically, TiO2 nanopowders incorporated into zein or other polymers were used to form antimicrobial coating on the container surface. The surface coatings were activated by visible light to inactivate E. coli O157:H7 on the container surface, which achieved more than 99.7% reductions of the pathogen. The research demonstrates that the developed methods and formula can be applied on different types of containers made of metal, wood, plastics, paperboard, etc., and for various foods, specially fruits and vegetables. 02 Novel antimicrobial phenolic fatty acids. New types of antimicrobials are needed as antibiotic resistance of bacteria has become more common. ARS researchers in Wyndmoor, Pennsylvania synthesized novel phenolic fatty acids and evaluated their antimicrobial properties against both Gram-positive and Gram-negative bacteria. Results showed that the compounds at low parts per million concentrations effectively inactivate Gram-positive bacteria. Further research indicates that carboxylic group in the fatty acid moiety and the hydroxyl group on the phenol moiety were responsible for the antimicrobial efficacy. The information could help scientists to develop more potent antimicrobials. Overall, the research demonstrates that the novel class of phenolic fatty acids has potential for use as antimicrobials against Gram- positive bacteria. 03 Development of high pressure processed cantaloupe puree. Cantaloupe is one of the most nutritious and popular fruits. It has a brief harvest period, and large amounts of cantaloupes spoil every year in the farm due to the lack of preservation techniques. ARS researchers in Wyndmoor, Pennsylvania developed a safe and effective method using high pressure to preserve cantaloupe as a puree. The high pressure processing achieved more than 99.999% reduction of inoculated Salmonella enterica and Listeria spp. without affecting quality. The information will help food processors to develop novel type of fresh fruit puree and to reduce food waste. 04 Lignin extracts as antimicrobials and antioxidants. Lignin is a natural component in plants and its extracts have antimicrobial and antimicrobial properties that can be incorporated into antimicrobial packaging materials. ARS researchers in Wyndmoor, Pennsylvania optimized extraction conditions for lignin extraction from corn stover residue. At these extraction conditions, lignin extract with the highest antimicrobial and antioxidant activities were obtained. Thus, optimized lignin extracts have the potential for their application in food and packaging materials. 05 Natural compounds to control human pathogens. Consumer concern over the use of synthesized antimicrobials to enhance microbial food safety has led to search of natural alternatives. Sophorolipids are a class of natural compounds that are composed of sugar and fat, and are produced by a number of yeasts. ARS researchers in Wyndmoor, Pennsylvania evaluated the antimicrobial activity of six sophorolipids purified from various culture media fermented by a highly productive yeast strain. Results demonstrated that sophorolipids in the cyclic configuration were more effective against Salmonella and Listeria spp. than those in the free acid form. The cyclic sophorolipids, when dissolved in low, non-toxic concentrations of ethanol, inactivated both aforementioned foodborne pathogens. Therefore, these newly purified natural antimicrobials may be applied to enhance microbial food safety.
Impacts
(N/A)
Publications
- Fan, X., Sokorai, K.J., Niemira, B.A., Mills, R.S., Zhen, M.Y. 2012. Quality of gamma ray-irradiated iceberg lettuce and treatments to minimize irradiation-induced disorders. HortScience. 47:1108-1112.
- Fan, X., Sokorai, K.J., Engemann, J., Gurtler, J., Liu, Y. 2012. Inactivation of L. innocua, S. Typhimurium, and E. coli O157:H7 on surface and stem scar areas of tomatoes using in-package ozonation. Journal of Food Protection. 75:1611-1618.
- Zhang, X., Fan, X., Solaiman, D., Liu, Z., Yan, R., Mukhopadhyay, S., Ashby, R.D. 2015. Inactivation of Escherichia coli O157:H7 in vitro and on the surface of spinach leaves by biobased surfactants. Food Control. doi: 10.1016/j.foodcont.2015.07.026. 60:158-165.
- Fisher, K.D., Bratcher, C., Jin, Z.T., Bilgili, S.F., Owsley, W.F., Wang, L. 2016. Evaluation of a novel antimicrobial solution and its potential for control E. coli O157:H7, non-O157:H7 shiga toxin-producing E. coli, Salmononella spp., and Listeria monocytogenes on beef. Food Control. 64:196-201.
- Wang, L., Zhao, L., Yuang, J., Jin, Z.T. 2015. Application of a novel antimicrobial coating on roast beef for inactivation and inhibition of Listeria monocytogenes during storage. International Journal of Food Microbiology. 211:66-72.
- Sarker, M.I., Liu, L.S., Fan, X. 2015. Boron derivatives as a source of 1- MCP with gradual release. Scientia Horticulturae. 188:36-43. DOI: 10.1016/ j.scienta.2015.03.017
- Ukuku, D.O., Mukhopadhyay, S., Geveke, D.J., Olanya, O.M., Niemira, B.A. 2016. Minimal thermal treatments for reducing bacterial population on cantaloupe rind surfaces and transfer to fresh-cut pieces. Journal of Food Protection. DOI:10.4315/0362-028X.JFP-16-046.
- Tunick, M.H., Thomas-Gahring, A.E., Van Hekken, D.L., Iandola, S.K., Singh, M., Qi, P.X., Ukuku, D.O., Mukhopadhyay, S., Onwulata, C.I., Tomasula, P. M. 2016. Physical and chemical changes in whey protein concentrate stored at elevated temperature and humidity. Journal of Dairy Science. 99:2372- 2383. DOI: 10.3168/jds.2015-10256.
- Jin, Z.T., Huang, M., Niemira, B.A., Cheng, L. 2016. Microbial reduction and sensory quality preservation of fresh ginseng roots using nonthermal processing and antimicrobial packaging. Journal of Food Processing and Preservation. doi: 10.1111/jfpp.12871.
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Progress 10/01/14 to 09/30/15
Outputs
Progress Report Objectives (from AD-416): To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416): An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/ g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh-cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf- life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re-growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. Within this fiscal year, research has been conducted to evaluate product quality changes as a result of antimicrobial treatments and to combine novel intervention technologies and treatments with antimicrobial coating and film to accomplish milestones in objectives 1, 2 and 4 of the project. Detailed progress to achieve the overall objectives is listed below. Optimizing extraction conditions for lignin extraction is in progress. Identifying and evaluating new antimicrobial materials are one of the important approaches to the development of antimicrobial food packaging. Our previous study demonstrated that lignin possesses antimicrobial and antioxidant properties. However these properties could be affected by the lignin extraction conditions using corn stover as a starting material. Different treatment temperatures, times, and solid-to-liquid ratios were investigated for yield, antimicrobial and antioxidant activities of lignin extracts. The optimum extraction conditions at 50 degrees C, 120 min, and 1/8 for the ratio of corn stover solids to extracting liquid (4% sodium hydroxide) resulted in 4.07 g lignin yield per 12g of corn stover residue. Thus, lignin byproducts showed the potential for their antioxidant and antimicrobial application. Aerosolized antimicrobials have a potential to be more effective in inactivating human pathogens than traditional sanitizer washing due to their higher penetration ability. A study was conducted to evaluate the effects of applying aqueous sanitizers as fine droplets on quality of tomatoes fruit. Cherry tomatoes were treated with atomized FDA (Food and Drug Administration)-approved sanitizers and with combinations of organic acids followed by 21 days of storage at 10 degree C. Changes in color, texture, and nutrients of treated fruit were evaluated in comparison with non-treated control fruits. Results showed that the treatments had no consistent effects on appearance, texture or contents of ascorbic acid, lycopene, and total antioxidants. Furthermore, the shelf-life of tomatoes was not impacted. The results demonstrated that aqueous sanitizers can be applied as an aerosol to maintain quality of tomatoes. Contamination of fresh or minimally processed produce with pathogenic bacteria remains a major public health concern. An integration of processing and packaging is advantageous from the point of safety and quality because treatment intensities required for each individual operation in the integrated treatment strategy are often less compared to single treatment method, which result in less negative impact on product quality. Research has been conducted to integrate organic acid wash with an advanced chlorine-based packaging system for treating tomato fruit. A 2-min wash of stem scar inoculated tomato under mild agitation in water containing 0.5 % of formic and acetic acid mixtures followed by chlorine- based antimicrobial packaging was able to cause a 6-log reduction of a three-serotype mixture of Salmonella enterica, leaving tomato completely free of target pathogen. The integrated treatment also achieved complete reduction of aerobic mesophilic background microorganisms. No visual alteration of color was observed. This integrated treatment approach using rapid acid washes followed by active antimicrobial packaging can ensure safe and effective removal of foodborne pathogens and would greatly benefit the produce industry. In collaboration with other scientists, a series of a newly synthesized phenolic fatty acids were tested for their antimicrobial and antioxidant properties. Results showed that the novel compounds were effective against Gram-positive bacteria such as Listeria, being able to inhibit the growth of bacteria at concentrations below 10 part per million. The compounds also had moderate antioxidant ability. Strawberry is a popular fruit with rich in vitamins and antioxidants, but the possible pathogen contamination is a concern. In this study, antimicrobial coating alone, or in combination with antimicrobial washing, was evaluated for the ability to inhibit the growth of a six-strain composite of E. coli O157: H7, Salmonella, and native microflora on strawberries. The combined treatments significantly inhibited the growth of E. coli O157:H7, Salmonella, and native bacteria as well as mold and yeast on strawberries over 3 weeks at 4 degree C. In addition, the coating treatment reduced the loss of weight and firmness, and color of strawberry during storage. Root, tuber and bulb crops come from soil, hence easily contaminated with pathogenic and spoilage microorganisms, resulting in short shelf life and safety concern. In this study, parsnip was used as a model food, and treated with the combination of sanitizer washing, antimicrobial coating and modified aerosphere package. Preliminary results show that total bacterial population did not grow during 74 days of storage at 4 degree C. Yeasts and molds were reduced to non-detectable level after the treatments and storage, and notable loss in quality was not observed. The treatments may be applied on tuber and root crops for reducing microbial contamination. Accomplishments 01 Antimicrobial packaging combined with pulsed electric field (PEF) pasteurization to improve quality and safety of juice. FDA requires all commercial juice and beverage products be pasteurized. ARS researchers at Wyndmoor, Pennsylvania, investigated an integrated approach for enhancing microbial safety and extending shelf life of juice and beverage products. In this study, pure pomegranate juice was processed in bench scale and commercial scale PEF systems, and packaged in antimicrobial-coated bottles. Juices treated with the combination of PEF and antimicrobial bottles had a shelf-life over 84 days, which significantly extended the microbiological shelf-life of pomegranate juice. The results demonstrated that the combination of antimicrobial packaging and PEF processing is an innovative approach for extending shelf-life and enhancing safety of juice. 02 Development of new edible coating solutions and films using natural biopolymers and nanotechnology. The contamination of foodborne pathogens in ready-to-eat meat products has been a concern for the meat industry. ARS researchers at Wyndmoor, Pennsylvania, developed edible antimicrobial composite films from micro-emulsions containing all- natural compounds using high pressure homogenization (HPH) technology. HPH treatment significantly reduced polymer particle sizes in the emulsion to about one micrometer. The films from the coating solution were softer, less rigid, and more stretchable than those without HPH treatments. The composite films inactivated Listeria innocua in a culture medium by 99.9999% after 2 days at 22 degree C and Listeria innocua on the surface of ready-to-eat meat samples by 99.99% after 35 days at 10 degree C. The new edible antimicrobial film and coating could be used to enhance safety of ready-to-eat foods. 03 Bio-based antimicrobials for safer fresh produce. Postharvest washing is an important step for controlling foodborne pathogens for the fresh produce industry. ARS researchers at Wyndmoor, Pennsylvania, investigated the feasibility of several types of bio-based antimicrobials on inactivation of Escherichia coli O157:H7 in wash water and on baby spinach leaves. Results demonstrated that a vitamin B1-derived compound and a bio-surfactant isolated from yeast reduced E. coli O157:H7 by more than 99%. Therefore, the natural and bio-based antimicrobials offer attractive and environmentally friendly alternatives to currently used sanitizer(s). 04 Development of novel antimicrobial formulation and safe and effective integrated treatment for produce safety. Chlorine is commonly used by the fresh produce industry. However, the efficacy of chlorine in inactivating human pathogens on fresh produce is very limited, and there is a concern on the formation of potential harmful chemical by- products. ARS researchers at Wyndmoor, Pennsylvania, developed a unique antimicrobial formulation, HEN, combining sanitizer activity of hydrogen peroxide with a surfactant (EDTA) and nisin. In a laboratory study, the integrated approach using a low dose (0.6 kilojoule per square meter) ultraviolet (UV) treatment in combination with 2 min wash in HEN yielded significantly higher inactivation (99.998%) of Salmonella spp. compared to current chlorine based wash (99.5%) alone on tomato fruit. Hence the newly developed integrated method employing a 10 sec UV treatment with 2 min washes in HEN solution is more effective than current chlorine-based washes. The new integrated approach can be used by fruit industry to reduce the contamination with foodborne pathogens. 05 Improving microbial safety of low moisture foods. Human pathogens such as B. cereus can survive well in low moisture foods such as flours over a long periods of time, and results in outbreaks of foodborne illness and recalls of contaminated products. ARS scientists in Wyndmoor, Pennsylvania, investigated the effectiveness of ionizing radiation on naturally contaminated B. cereus (both spores and vegetative forms) in mesquite pod flour. The flour, a gluten-free food, is one of the most important food staples for indigenous people. Results showed that irradiation at a moderate dose of 6 kilogray reduced population of the pathogen in the flour with initial population of more than 100,000 cells per gram to a non-detectable level. The information from the study would be helpful to FDA in making a science-based decision for the approval of irradiation of low-moisture foods and to food industry in enhancing the microbial safety of low moisture food.
Impacts
(N/A)
Publications
- Jin, Z.T., Guo, M., Yang, R. 2014. Combination of pulsed electric field processing with antimicrobial bottle for extending microbiological shelf- life of pomegranate juice. International Journal of Food Science and Technology. 26:153-158.
- Fan, X. 2014. Furan formation from fatty acids as a result of storage, gamma irradiation, UV-C and heat treatments. Journal of Agricultural and Food Chemistry. DOI:10.1016/j.foodchem.2014.12.002.
- Jin, Z.T., Guo, M., Zhang, H.Q. 2015. Upscaling from benchtop processing to industrial scale production: More factors to be considered for pulsed electric field food processing. Journal of Food Engineering. 146:72-80.
- Yun, J., Fan, X., Li, X., Jin, Z.T., Jia, X., Mattheis, J.P. 2015. Natural surface coating to inactivate Salmonella enterica Serovar Typhimurium and maintain quality of cherry tomatoes. International Journal of Food Microbiology. 193:59-67.
- Gurtler, J., Bailey, R., Jin, Z.T., Fan, X. 2014. Inactivation of an E. coli 0157:H7 and Salmonella composite on fresh strawberries by varying antimicrobial washes and vacuum perfusion. International Journal of Food Microbiology. 139:113-118.
- Kara, H.H., Xiao, F., Sarker, M.I., Jin, Z.T., Sousa, A.M., Liu, C., Tomasula, P.M., Liu, L.S. 2015. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging. Journal of Applied Polymer Science. DOI: 10.1002/APP.42475.
- Mukhopadhyay, S., Ukuku, D.O., Juneja, V.K. 2015. Effects of different combined non-thermal treatments against Salmonella enterica on plum tomatoes. Food Control. 56:147-154. DOI: 10.1016/j.foodcont.2015.03.020.
- Juneja, V.K., Cadavez, V., Gonzales-Barron, U., Mukhopadhyay, S. 2014. Modelling the effect of pH, sodium chloride and sodium pyrophosphate on the thermal resistance of Escherichia coli O157:H7 in ground beef. Food Research International. 69:289-304.
- Lacombe, A.C., Niemira, B.A., Gurtler, J., Fan, X., Sites, J.E., Boyd, G., Chen, H. 2015. Atmospheric cold plasma inactivation of Aerobic Microorganisms on blueberries and effects on quality attributes. Food Microbiology. 46:479-484.
- Gurtler, J., Bailey, R., Cray, W.C., Hinton Jr, A., Meinersmann, R.J., Ball, T.A., Jin, Z.T. 2015. Salmonella spp. isolated from ready-to-eat pasteurized liquid egg produce: thermal resistance, biochemical profile, and fatty acid analysis. International Journal of Food Microbiology. 206:109-117.
- Ukuku, D.O., Onwulata, C.I., Thomas-Gahring, A.E., Mukhopadhyay, S., Tunick, M.H. 2014. Behavior of native microbial populations of WPC-34 and WPC-80 whey protein stored at different temperatures. Journal of Food Processing and Technology. DOI: 10.4172/2157-7110l.1000304.
- Fan, X., Sokorai, K.J. 2015. Formation of trichloromethane in chlorinated water and fresh-cut produce and as a result of reacting with citric acid. Postharvest Biology and Technology. 109:65-72.
- Fan, X., Felker, P., Sokorai, K.J. 2015. Decontamination of mesquite pod flour, naturally contaminated with Bacillus cereus and formation of furan by ionizing irradiation. Journal of Food Protection. 78(5):954-962.
- Zhang, Q., Mukhopadhyay, S., Hwang, C., Xu, X., Juneja, V.K. 2015. Modeling the survival of Salmonella on slice cooked ham as a function of apple skin polyphenols, acetic acid, oregano essential oil and carvacrol. Journal of Food Processing and Technology. DOI: 10.1111/jfpp.12486.
- Ukuku, D.O., Geveke, D.J., Mukhopadhyay, S., Olanya, O.M., Juneja, V.K. 2014. Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta. Journal of Food Processing and Technology. 5:385.
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416): An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/ g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh-cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf- life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re-growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. Within this FY, research has been conducted to evaluate product quality changes as a result of antimicrobial treatments and to explore a new way of formulating antimicrobial coating and film to accomplish objectives 1 and 2 of the project. In addition, antimicrobials have been applied alone, in combinations and as electrostatic spraying to address objective 4 of the project. Detailed progress to achieve the overall objectives is listed below. Quality of fruits and vegetables as a result of intervention technologies/treatments has to be investigated before the intervention being considered for commercial application. Cherry tomatoes were treated with combinations of different types of acids and with the combination of acids and essential oil. Sensory properties (color, texture, smell and appearance) of treated fruit were evaluated during 21 days of storage at 10 C. Results suggested that the treatments with mustard oil resulted in a residue odor on tomato fruit. However, other formulations did not significantly affect sensory quality of cherry tomatoes while enhancing microbial safety. Development of new edible coating solutions and films using natural biopolymers and nanotechnology is in progress. Coating solutions with natural polymers and emulsifiers were treated by high pressure homogenization (HPH, 138 MPa, 3 cycles). HPH treatment significantly reduced polymer particle sizes in the emulsion to about one micrometer. Resultant films from the coating solution were softer, less rigid and more stretchable than those without HPH treatments. The coating films form micro channels and pores that would facilitate the release of antimicrobials/antioxidants, and modify barrier properties to CO2, O2, moisture, and UV light. The HPH treated films showed higher antimicrobial efficiency than non-HPH treated films. Contamination of fresh or minimally processed produce with human pathogens still remains a high concern. Minimally processed spinach and tomato contaminated with pathogens have been associated with multiple outbreaks of foodborne illnesses. Studies were conducted to investigate the ability of hydrogen peroxide (H2O2) to inactivate human bacterial pathogens and spoilage microflora on leafy green and tomatoes. In a preliminary experiment, 3% H2O2 was proven to be more effective than 5% H2O2. A 3% solution of H2O2 was capable of reducing population of a five- strain cocktail of E. coli O157:H7 on baby spinach and three serotypes mixture of Salmonella enterica on tomato by more than 99% in a 3 minute wash under mild agitation. Non-thermal treatments utilizing ultraviolet light (0.60 kJ/m2) and 3% H2O2 provided a strong synergy inactivating greater than 99.99% of both E. coli O157:H7 and Salmonella enterica on spinach and tomato. Ultraviolet light is FDA approved surface decontamination technique and H2O2 is classified as a generally recognized as safe substance. Hence this combination technology may ensure safe and effective inactivation of foodborne pathogens on produce and would greatly benefit the food industry. It is suspected that the use of communal dump tanks could serve as a source of contamination in fresh and fresh-cut produce processing. Electrostatic spraying offers a non-recirculating technique for applying sanitizers on fresh and fresh-cut produce. An electrostatical spraying system was acquired and a treatment chamber specific for the spraying system was built to test treatment efficiency. The uniformity of spraying coverage on tomato fruit was evaluated in terms of the spraying time and charge (positively vs negatively) of antimicrobials. The effect of electrostatic spray of a peroxyacetic acid-based sanitizer, organic acids and plant extracts on E. coli and Salmonella Typhimurium was conducted on tomato fruit. Initial results suggested the treatments reduced population of the bacteria by 90-99%. The system needs to be optimized to achieve better results. Mesquite pod flour has been involved in recent recalls due to contamination with Bacillus cereus. Non-thermal processing technology is needed to reduce the population of microorganisms in the flour because heating deteriorates its desired characteristic flavor. A study was conducted to investigate the efficacy of ionizing irradiation in decontaminating two types of mesquite pod flour naturally contaminated with B. cereus and to evaluate the effect of irradiation on formation of furan, a possible human carcinogen. The information generated from the study would be helpful to food industry to enhance the microbial safety of the product. Following initial screening a variety of antimicrobials, validation tests were conducted at USDA-ARS against E. coli O157:H7 and Salmonella spp. on ground meat trims to confirm and validate the efficacy of the best antimicrobials. Selected antimicrobials from the validation test result were experimented on a large scale CO2 plus platform at our collaborator�s site (Air Liquide). An abstract entitled "The Use of Liquid CO2 as a Conveying and Dispersing Agent to Simultaneously Chill Meat Products and Broadcast Various Anti-Microbial Processing Aids during a Meat Mixing Process" was approved by cooperators (USDA & Air Liquide), which will be presented at the 2014 International Association for Food Protection Annual Meeting at Indianapolis, Indiana. Accomplishments 01 Chlorine by-product formation in wash water and fresh-cut produce. Chlorine (sodium hypochlorite) is a commonly used sanitizer by the food industry while citric acid is often used to adjust its pH in order to achieve higher efficacy of the chlorine treatment. However, formation of chlorine by-products is a concern due to their potential adverse health effect. ARS researchers at Wyndmoor, Pennsylvania studied the formation of trichloromethane (a chlorine by-product) in water, and fresh-cut produce and as affected by the presence of citric acid. Results showed that trichloromethane was formed in chlorated water, but not in chlorine dioxide solution. Higher amount of trichloromethane (up to 280 ng/mL) was produced in the chlorine solution used for washing cut-lettuce than for diced onions while levels of trichloromethane in the final products (cut vegetables) were much lower (14-22 ng/g) than that in the water. Citric acid reacted with chlorine producing more than 1,000 ng/mL of trichloromethane in chlorine solution. Therefore, citric acid should be replaced with other pH adjustors to reduce the formation of trichloromethane in wash water. The information can be used by the produce industry to minimize the formation of chlorine by- products in water and fresh produce. 02 Double-layer antimicrobial packaging films for ready-to-eat (RTE) meat. The contamination of foodborne pathogens in RTE meat products has been a concern for the meat industry. ARS researchers at Wyndmoor, Pennsylvania developed edible chitosan-acid solutions incorporating antimicrobials on polylactic acid (PLA) packaging films to produce double-layer antimicrobial packaging films. The films reduced 99.9 percent of Listeria and 99 percent of Salmonella on RTE meat and inhibited their growth over 5 weeks at 10 C. This study provides the packaging industry and RTE meat processors a new way to provide safer products to consumers. 03 Antimicrobial coatings for fresh strawberry. Strawberries are esteemed as healthful and rich in vitamins and antioxidants. However, a 2011 outbreak of hemorrhagic colitis, which resulted in the death of two individuals, was associated with contaminated strawberries. ARS researchers at Wyndmoor, Pennsylvania developed antimicrobial coating formulas to kill pathogens and spoilage microorganism on fresh strawberry. The coating treatments were capable of reducing Salmonella and E. coli O157:H7 by more than 99.9% on strawberry. No mold growth and appearance change were observed for the treated samples stored at 4 C for 19 days. Results from this study will provide processors with viable options for designing antimicrobial coatings to improve the microbiological safety and quality of strawberry. 04 UV-C treatment for safer tomato. UV-C treatment is a simple and inexpensive processing technology which leaves no chemical residues behind. The impact of UV-C on E. coli O157:H7 and Salmonella population on tomato fruit was conducted by ARS researchers at Wyndmoor, Pennsylvania. Results showed that surface characteristics, i.e., rough stem scar vs. smooth surface played an important role in bacterial attachment and inactivation as pathogen reductions were lower when pathogens were located at the stem scar site compared to smooth surface. A UV-C dose of kilojoules per square meter 6 kJ/m2 was capable of reducing the viable population of E. coli O157:H7 and Salmonella enterica by more than 99.9%. Yeast and mold population was reduced by about 99% by the same treatment. The firmness and color of the tomatoes were not affected by the UV-C doses during post-treatment storage. Hence UV-C treatment may prove worthy to use in post-harvest situations to improve safety and maintain quality of tomatoes.
Impacts
(N/A)
Publications
- Sampedro, F., Phillips, J.G., Fan, X. 2013. Use of response surface methodology to study the combined effects of UV-C and thermal process on vegetable oxidative enzymes. LWT - Food Science and Technology. 55:189-196.
- Guo, M., Jin, Z.T., Wang, L., Scullen, B.J., Sommers, C.H. 2013. Antimicrobial films and coatings for inactivation of Listeria innocua on ready-to-eat deli turkey meat. Food Control. 40:64-70.
- Mukhopadhyay, S., Ukuku, D.O., Juneja, V.K., Fan, X. 2014. Effects of UV-C treatment on inactivation of Salmonella and Escherichia coli O157:H7 on tomato surface and steam scars, native microbial loads, and quality of grape tomatoes. Food Control.
- Yun, J., Yan, R., Fan, X., Gurtler, J., Phillips, J.G. 2013. Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit following UV-C light. International Journal of Food Microbiology. 166:356-363.
- Kingsley, D.H., Vincent, E., Meade, G.K., Watson, C., Fan, X. 2014. Inactivation of human norovirus using chemical sanitizers. International Journal of Food Microbiology. 171:94-99.
- Yan, R., Mattheis, J.P., Gurtler, J., Sites, J.E., Fan, X. 2014. UV-C inactivation of Escherichia coli and dose uniformity on apricot fruit in a commercial setting. Postharvest Biology and Technology. doi.org/10.1016/j. postharvbio.2014.04.005.
- Juneja, V.K., Mukhopadhyay, S., Ukuku, D.O., Hwang, C., Wu, V.C., Harshavardhan, T. 2014. Interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga-toxin producing Escherichia coli O104:H4. Journal of Food Protection. 77(5):706-712 doi:10.431/0362- 028XJFP-13-387.
- Ukuku, D.O., Yamamoto, K., Bari, M., Mukhopadhyay, S., Juneja, V.K., Kawamoto, S. 2013. Membrane damage and viability loss of thermally treated and high hydrostatic pressurized E. coli 0157:H7 and Salmonella spp. in apple juice. Journal of Food Processing and Technology. 4:236 doi:10.4172/ 2157-7110.1000236.
- Guo, M., Jin, Z.T., Yang, R. 2014. Antimicrobial polylactic acid packaging films against Listeria and Salmonella in culture medium and on ready-to- eat meat. Food and Bioprocess Technology. DOI:10.1007/s11947-014-1322-x.
- Guo, M., Jin, Z.T., Geveke, D.J., Fan, X., Sites, J.E., Wang, L. 0203. Evaluation of microbial stability, bioactive compounds, physicochemical properties, and consumer acceptance of pomegranate juice processed in a commercial scale pulsed electric field system. Food and Bioprocess Technology. DOI:10.1007/s11947-013-1185-6.
- Sampedro, F., Fan, X. 2014. Inactivation kinetics and photoreactivation of vegetable oxidative enzymes after combined UV-C processing. Innovative Food Science and Emerging Technologies. 23:107-113.
- Sampredo, F., Mcaloon, A.J., Yee, W.C., Fan, X., Geveke, D.J. 2014. Cost analysis and environmental impact of nonthermal technologies. Food and Bioprocess Technology. DOI:10.1007/s11947-014-1298-6.
- Onwulata, C.I., Tunick, M.H., Mukhopadhyay, S. 2014. Flow behavior of mixed-protein incipient gels. International Journal of Food Properties. 17(6):1283-1302.
- Ukuku, D.O., Mukhopadhyay, S., Olanya, O.M. 2013. Effect of organic acid treatments on microbial safety and overall acceptability of fresh-cut melon cubes. International Journal of Food, Agriculture, and the Environment. 11(3&4):340-345.
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Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416): An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/ g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh-cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf- life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re-growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. Research has been conducted to develop antimicrobial coatings for controlling pathogens, to identify compounds of potential concern formed by novel non-thermal food processing interventions, and to develop/ optimize treatment processes and combinations to control pathogens. Detailed progress to achieve the overall objectives is listed below. Ready-to-eat (RTE) meat products can be more vulnerable to cross- contamination due to multiple steps involved in preparation. The newly designed antimicrobial coatings and films with chitosan and lauric arginate ester significantly reduced Listeria innocua and Salmonella on RTE deli meat products. Combining antimicrobial coatings or films with steam flash pasteurization further reduced L. innocua, achieving more than 99.999% reduction of L. innocua. Chlorine is a commonly used chemical sanitizer in the food industry. However, harmful chemical by-products may be formed from chlorine reacting with organic materials. The formation of trichloromethane, a chlorine by-product, was evaluated in fresh-cut produce and wash water. Results suggested that more than 10 times higher levels of trichloromethane were detected in wash water than actual fresh-cut lettuce. Antibrowning solutions contaminated with L. monocytogenes have resulted in recalls of cut fruit in recent years. Several antimicrobials and antibrowning compounds were tested using a central composite design to optimize formulations to preserve the freshness of cut apple while inactivating L. monocytogenes. Most of the experiments have been completed and data are being analyzed. Antimicrobials applied as a coating onto the inner surface of packages need to migrate into packaged food to exert their effect on pathogenic bacteria. The releasing kinetics of two common antimicrobials (benzoate and sorbate) was tested in models systems. Significantly higher amount of benzoate (~800 ppm) compared to sorbate (~500 ppm) was detected in water media from the bottle coating. Migration of these antimicrobial into water followed a first order kinetics. High pressure processing (HPP) is an approved non-thermal pasteurization process that can inactivate pathogens and undesirable spoilage enzymes with minimal alteration of sensory and nutritional qualities. Freshly prepared mixed fruit salad, artificially inoculated with three strains mixture of Salmonella Stanley, S. Newport, and S. Saintpaul, was treated with HPP at various pressures and times. At a pressure of 300 megapascal and temperature of 25 C, a 5-min HPP treatment inactivated 99.999% of three strains mixture of S. Stanley, S. Newport, and S. Saintpaul in freshly prepared mixed fruit salad. Accomplishments 01 Ultraviolet (UV) light to enhance fruit safety. Tree-ripe fruit such as apricots and peaches can not be washed with chemical sanitizers due to their softness. Non-aqueous technologies are needed to minimize the risk of human pathogens on this type of fruit. ARS researchers at Wyndmoor, Pennsylvania evaluated the efficacy of UV-C light for the inactivation of two common pathogenic bacteria on apricot. The population of pathogens decreased with increased doses of UV-C. A short (10 sec) UV-C treatment resulted in immediate reduction of 99% of Salmonella spp. and E. coli O157:H7 on apricot surface. During post-UV storage, the pathogens on UV-C exposed fruit did not survive well and continued to decrease in population. Compared with the non-treated fruit, up to 99.999% of pathogens was reduced after post-UV-C storage. The low-cost UV-C technologies can be employed by the fruit industry to meet the increasing demand of high quality and safe fruit. 02 Antimicrobial coatings in combination with other intervention technologies effectively decontaminate raw and ready-to-eat (RTE) shrimps. ARS researchers at Wyndmoor, Pennsylvania investigated the antimicrobial effects of ozone, antimicrobial coating and cryogenic freezing, used alone or in combination, on the survival of Listeria innocua, a surrogate of L. monocytogenes on raw whole and RTE shrimp. Results indicated that antimicrobial coating in combination with cryogenic freezing reduced more than 99.999% of L. innocua and natural bacteria on raw shrimp and the coating treatments also significantly inhibited Listeria growth on RTE shrimp thawed at 4, 10 or 22 degree C for either 24 or 48 h. The information is valuable for seafood processors and distributors to adopt intervention strategies to enhance the safety and extend the shelf-life of shrimp. 03 Formation of carcinogenic furan from fatty acids. Furan is a potential human carcinogen. ARS researchers at Wyndmoor, Pennsylvania studied the mechanisms for furan formation from different fatty acids as a result of thermal and nonthermal processing and storage. Results suggested that furan was mainly produced from unsaturated fatty acids such as linoleic and linolenic acid. And furan was induced from the unsaturated fatty acids by thermal and UV-C treatments. Furthermore, storage of unsaturated fatty acid emulsions at ambient temperature led to formation of low levels of furan even without the exposure to high temperature or UV-C. The results would help food industry to develop strategies to minimize the formation of furan from fat-containing food, and regulatory agencies to make science-based policies.
Impacts
(N/A)
Publications
- Yun, J., Fan, X., Li, X. 2013. Inactivation of Salmonella enterica serovar Typhimurium and quality maintenance of cherry tomatoes treated with gaseous essential oils. Journal of Food Science. 78(3)458-464.
- Guo, M., Yang, R., Antenucci, R., Mills, B., Cassidy, J.M., Scullen, O.J., Sites, J.E., Rajkowski, K.T., Sommers, C.H., Jin, Z.T. 2013. Inactivation of natural microflora and Listeria innocua on raw whole shrimp by ozonated water, antimicrobial coatings, and cryogenic freezing. Food Control. 34:24- 30.
- Jin, Z.T., Gurtler, J., Li, S. 2013. Development of antimicrobial coatings for improving the microbiological safety and quality of shell eggs. Journal of Food Protection. 76(5)779-785.
- Sampedro, F., Mcaloon, A.J., Yee, W.C., Fan, X., Zhang, H.Q., Geveke, D.J. 2013. Cost analysis of commercial pasteurization of orange juice by pulsed electric fields. Innovative Food Science and Emerging Technologies. 17:72- 78.
- Yun, J., Li, X., Fan, X., Zhang, M., Il, W. 2012. Growth and quality of soybean sprouts (Glycine max L. Merrill) as affected by gamma irradiation. Journal of Radiation Physics and Chemistry.
- Yuk, H., Sampedro, F., Fan, X., Geveke, D.J. 2012. Nonthermal processing of orange juice using a pilot-plant scale supercritical carbon dioxide system with a gas-liquid metal contactor. Journal of Food Processing and Preservation. DOI:10.1111/jfpp.12013.
- Ukuku, D.O., Mukhopadhyay, S., Onwulata, C.I. 2013. Effect of storage temperature on survival and recovery of thermal and extrusion injured Escherichia coli populations in whey protein concentrate and corn meal. Foodborne Pathogens and Disease. Volume 10(1):62-68.
- Li, W., Jin, Z.T., Liu, L.S. 2012. Antimicrobial activity of allyl isothiocyanate used to coat biodegradable composite films as affected by storage and handling conditions. Journal of Food Protection. 75(12):2234- 2237.
- Ray, S., Jin, Z.T., Fan, X., Liu, L.S., Yam, K. 2013. Development of chlorine dioxide releasing film and its application in decontaminating fresh produce. Journal of Food Science. 78(2):M276-M284.
- Guan, W., Fan, X., Yan, R. 2013. Effects of combination of ultraviolet light and hydrogen peroxide on inactivation of Escherichia coli O157:H7, native microbial loads, and quality of button mushrooms. Food Control. 34:554-559.
- Juneja, V.K., Mukhopadhyay, S., Marks, H.L., Mohr, T., Warning, A., Datta, A. 2013. Predictive thermal inactivation model for effects and interactions of temperature, NaCl, sodium pyrophosphate and sodium lactate on Listeria monocytogenes in ground beef. Food and Bioprocess Technology. DOI:10.1007/s11947-013-1102-z.
- Mukhopadhyay, S., Ukuku, D.O., Fan, X., Juneja, V.K. 2013. Efficacy of integrated treatment of UV light and low dose gamma irradiation on Escherichia coli O157:H7 and Salmonella enterica on grape tomatoes. Journal of Food Science. DOI:10.1111/1750-3841.12154.
- Fan, X. 2012. Irradiation of fresh and fresh-cut fruits and vegetables: quality and shelf-life. Book Chapter. 274-294. In. Fan, X and Sommers, C.H. (eds.): Food Irradiation: Research and Technology, 2nd Edition. Willy- Blackwell, West Sussex, United Kingdom. 446 pp.
- Igual, M., Sampedro, F., Martinez-Navarrete, N., Fan, X. 2013. Combined osmodehydration and high pressure processing on the enzyme stability and antioxidant capacity of a grapefruit jam. Journal of Food Engineering. 114:514-521.
- Guo, M., Scullen, O.J., Sommers, C.H., Jin, Z.T. 2013. Effects of antimicrobial coatings and cryogenic freezing on survival and growth of Listeria innocua on frozen ready-to-eat shrimp during thawing. Journal of Food Science. 78(8):1195-1200.
- Fan, X. 2012. Radiation chemistry of major food components. Book Chapter. 75-98. In: Fan, X and Sommers, C.H. (eds.): Food Irradiation: Research and Technology, 2nd Edition. Willy-Blackwell, West Sussex, United Kingdom. 446 pp.
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416): An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh- cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf-life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re- growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. Organic acids are generally recognized as safe. Effects of common organic acids and electrolyzed water have been investigated as alternatives to chemical sanitizers for decontamination of fresh fruits and vegetables. Results indicate that organic acids such as acetic, lactic, malic, and citric acid can reduce the population of Salmonella spp. inoculated onto tomatoes by 96.8-99.9%. Some soft fruits such as tree-ripe apricots cannot be washed without damaging quality. Studies were conducted to evaluate the efficacy of ultraviolet light (UV-C) for inactivation of Salmonella and E. coli O157:H7 on tomato and apricot. Both Salmonella and E. coli O157:H7 populations decreased with increased doses of UV. Results suggest that a 10-second UV-C treatment can reduce 99% of Salmonella spp. and E. coli O157:H7 inoculated onto tomatoes or apricot. Salmonella exhibited slightly higher resistance to UV-C compared with E. coli O157:H7. In addition, UV light in combination with liquid phase ozone (1.4 parts per million) reduced 99.99% of Salmonella in an agitated system with surging bubbles. Antimicrobial coatings with edible and non-edible polymers and natural antimicrobials were developed for inactivating pathogens on shell eggs. Results show that the antimicrobial coatings were able to reduce up to 99. 9999% of Salmonella cells on eggs. There was no re-growth of the pathogen on eggs after coating treatments and during the 28 days� storage at 7 Degrees C. Results also indicated that the coatings were able to reduce the weight loss of eggs during storage at 7 or 4 Degrees C. Furan is a potential human carcinogen. The formation of furan was studied in model food systems as affected by heating, ultraviolet, and gamma radiation. Fatty acids and sugars as possible procurers of the compound were further investigated. Results suggest that changes in food composition would influence furan formation as a result of thermal and non-thermal processing. Based on one survey, one eighth of shrimp samples in the U.S. market is contaminated with L. monocytogenes, a pathogen causing listeriosis. The antimicrobial effects of ozone, antimicrobial coating, and cryogenic freezing, used alone or in combination, on survival of Listeria innocua (a surrogate of L. monocytogenes) on shrimp were investigated. Results indicated that antimicrobial coating in combination with cryogenic freezing reduced more than 99.999% of L. innocua and natural bacteria. The antimicrobial activity of three essential oils and their major components were evaluated as a gaseous treatment to reduce Salmonella Typhimurium on tomatoes. Texture, color, vitamin C, and lycopene contents of tomatoes were also analyzed after treatments. Results showed that treatment with gaseous cinnamon and oregano essential oils reduced Salmonella on tomatoes by 99.99% and maintained quality of the fruit. Accomplishments 01 Antimicrobial coatings effectively inactivate foodborne pathogens. Pathogenic contamination of food usually starts from food surfaces. The presence and potential growth of pathogens in food during storage and transportation is a safety concern. ARS researchers at Wyndmoor, Pennsylvania, used antimicrobial coatings to kill pathogens on food surfaces and to prevent further cross-contaminations during transportati storage, and store display. The coating treatments were capable of reducing Salmonella by more than 99.9999% on cantaloupe, tomato stem sca and shell eggs, and no re-growth during 14 days storage at 10 Degrees C. Results from this study will provide food processors with viable options for designing antimicrobial coatings to improve the microbiological safe and quality of produce. 02 In-package pasteurization for fresh and fresh-cut produce. Fresh fruits and vegetables are usually consumed by consumers directly without a cooking step to kill foodborne pathogens. Any pathogenic contamination fresh fruits and vegetables can potentially cause severe illnesses or ev deaths. ARS researchers at Wyndmoor, Pennsylvania, developed an in- package chlorine dioxide releasing film that can kill pathogens on packaged foods. Results indicated antimicrobial films in a food contain can inactivate 99.9% of Salmonella inoculated onto fresh grape tomatoes and some other types of produce. The in-package pasteurization provides single, simple, inexpensive technique to enhance the microbial safety an extend the shelf-life of packaged fresh and fresh-cut produce. 03 Integrated approach to enhance microbial safety of tomato fruits. Fresh tomatoes have been implicated in recent outbreaks of foodborne diseases. ARS researchers at Wyndmoor, Pennsylvania integrated ultraviolet C (UV-C light with low dose gamma radiation to control human pathogens on tomato fruits. Results indicated greater than 99.999% of E. coli O157:H7 and Salmonella enterica strains inoculated onto tomato fruits was inactivate by a combined treatment of low dose UV-C and gamma radiation. Furthermo this treatment significantly reduced the population of native microbes during 3 weeks of storage at 10 Degrees C, without causing substantial quality changes in tomatoes. This approach may be used by the produce industry to decontaminate fresh tomatoes.
Impacts
(N/A)
Publications
- Jin, Z.T., He, Y. 2012. Antibacterial activities of magnesium oxide (MgO) nanoparticles against foodborne pathogens. Journal of Nanoparticle Research. 13:6877-6885.
- Chen, W., Jin, Z.T., Gurtler, J., Geveke, D.J., Fan, X. 2012. Inactivation of Salmonella on whole cantaloupe by application of an antimicrobial coating containing chitosan and allyl isothiocyanate. International Journal of Food Microbiology. 155:165-170.
- Dong, X., Dong, M., Lu, Y., Turley, A., Jin, Z.T., Wu, C. 2011. Antimicrobial and antioxidant activities of lignin from residue of corn stover to ethanol production. Industrial Crops and Products. 34(3):1629- 1634.
- Fan, X., Guan, W., Sokorai, K.J. 2012. Quality of fresh-cut iceberg lettuce and spinach irradiated at doses up to 4kGy. Journal of Radiation Physics and Chemistry. 81:1071-1075.
- Li, X., Yun, J., Fan, X., Xing, Y., Yao, T. 2012. Effect of 1- methylcyclopropene and modified atmosphere packaging on chilling injury, and antioxidative defensive mechanism of sweet pepper. African Journal of Biochemistry Research. 10:6581-6589.
- Mukhopadhyay, S., Ukuku, D.O., Phillips, J.G., Juneja, V.K. 2012. Survival and growth of Salmonella Enteritidis in membrane processed liquid egg white with pH, temperature and storage conditions as controlling factors. Food Microbiology. 75(7):1219-1226.
- Fan, X., Lee, E.J., Ahn, D. 2011. Volatile sulfur compounds in foods as a result of ionizing radiation. In: Qiang, M., Fan, X., Mahattanatawee, K., editors. American Chemistry Society Book Chapter. Book chapter for ACS Publications. Washingnton, DC: American Chemical Society. p. 243-258.
- Li, W., Li, X., Fan, X., Tang, Y., Yun, J. 2012. Response of antioxidant activity and sensory quality in fresh-cut pear as affected by high O2, active packaging compared with low O2 packaging. Food Science and Technology International. 18:197-205.
- Mukhopadhyay, S., Ramaswamy, R. 2011. Application of emerging technologies to control Salmonella in foods: a review. Food Research International. 45:666-677
- Jin, Z.T., Gurtler, J. 2012. Inactivation of Salmonella on tomato stem scars by edible chitosan and organic acid coatings. Journal of Food Protection. 75(8):1368-1372.
- Gurtler, J., Jin, Z.T. 2012. Propyl paraben sensitizes heat-resistant Salmonella Enteritidis and Oranienburg to thermal inactivation in liquid egg albumen. Journal of Food Protection. 75(3):443-448.
- Yun, J., Li, X., Fan, X., Yao, T., Xiao, Y., Wan, S. 2012. Effect of gamma irradiation on microbial load, physicochemical and sensory characteristics of soybeans (Glycine max L. Merrill). Journal of Radiation Physics and Chemistry. 81:1198-1202.
- Yadav, M.P., Strahan, G.D., Mukhopadhyay, S., Hotchkiss, A.T., Hicks, K.B. 2011. Fomation of corn fiber gum-milk protein conjugates and their molecular characterization. Food Hydrocolloids Journal. 26:326-333.
- Ukuku, D.O., Onwulata, C.I., Mukhopadhyay, S. 2012. Behavior of Escherichia coli bacteria in whey protein and corn meal during twin screw extrusion processing at different temperatures. Journal of Food Processing and Technology. 3(4):1000150.
- Tomasula, P.M., Mukhopadhyay, S., Datta, N., Porto Fett, A.C., Call, J.E., Luchansky, J.B., Renye Jr, J.A., Tunick, M.H. 2011. Pilot-scale crossflow- microfiltration and pasturization to remove spores of Bacillus anthracis (Sterne) from milk. Journal of Dairy Science. 94:4277-4291.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) To determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions. To develop antimicrobial packaging-based treatments for controlling pathogens. To identify compounds of potential concern formed by novel non-thermal food processing interventions. To develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value. Approach (from AD-416) An integrated approach to enhance microbial safety while maintaining product quality will be adopted by combining efficacious treatments and processes with antimicrobial packaging. Current antimicrobial treatments, processes, and intervention technologies that have been demonstrated to be effective in inactivating human pathogens will be modified and evaluated to confirm their effectiveness in obtaining a minimum 3 log CFU/g reduction of E. coli O157:H7 and Salmonella spp. on fresh and fresh- cut produce (mainly leafy green vegetables and tomatoes). Novel intervention technologies with higher efficacy of pathogen reduction will be developed and optimized. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf-life will be determined using the intensity (time, concentration, dose, etc.) that achieves a 3-log CFU/g reduction of the pathogens. In addition, new antibrowning/antimicrobial formulas will be developed to minimize risk of L. monocytogenes contamination during processing of cut fruit while inhibiting tissue browning. Furthermore, accumulation of chemical by-products as a result of chemical sanitizers and physical interventions will be investigated. Antimicrobial packaging as the final defense against human pathogens will be developed for a variety of food products (fresh-cut produce, meats, etc.) to reduce or control the re- growth of surviving pathogens during storage. Finally, combinations of efficacious intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Strategies and treatments will be developed to minimize adverse effects of intervention technologies and antimicrobial packaging on product quality. By combining efficacious intervention technologies and treatments with antimicrobial packaging, a 5-log reduction of common pathogens may be achieved. Intervention technologies either alone or in combination with antimicrobial packaging will be transferred to industry to enhance microbial safety of commercial food products. A new coating solution has been developed to apply on tomatoes and cantaloupes. Experimental results showed that the coating treatment effectively reduced the population of Salmonella by more than 6 log- cycles in tomato stem scars and up to 5 log-cycles on cantaloupes. No re- growth occurred during 14 days storage at 10 C in both tomato and cantaloupes. The coating solution can significantly enhance microbiological safety of tomatoes and cantaloupe with no adverse effect on tomato�s quality. Antioxidant activities, organoleptic properties, and consumer acceptance of spinach leaves treated with radiation at doses up to 4 kilogray (the maximum permissible dose) were evaluated. Results showed that none of organoleptic properties were affected by irradiation at doses up to 2 kilogray, and overall antioxidants contents of spinach were not consistently affected by irradiation at any dose. Therefore, low-dose irradiation may be used to enhance microbial safety without affecting consumer acceptance or overall antioxidant values of irradiated spinach. The effects of ultraviolet light (UV-C) treatment alone or in combination with low-dose gamma irradiation on microbial loads and qualities of tomatoes and mushrooms were studied. Results showed that UV- C or its combination with low dose gamma irradiation reduced populations of native microflora and Escherichia coli O157:H7 inoculated on mushrooms and tomatoes. The treatment effectiveness was slightly higher for pathogens located on the skin compared to stem scar sites of tomatoes. UV-C treatments also inhibited development of brown spot on the mushroom surface. Therefore, UV-C radiation or its combination could potentially be used for sanitizing fresh button mushrooms and tomatoes, and extending shelf-life. A novel in-package ozonation system was evaluated for its effectiveness in reducing populations of Escherichia coli O157:H7, Salmonella spp. and Listeria spp. on tomatoes. High levels of ozone were generated within 1 min using the dielectric barrier discharge technology inside the packages containing tomatoes. The treatment effectively reduced the populations of microorganisms by 2-5 log-cycles, even in inaccessible sites such as the stem scar area. Longer treatment times did not further reduce microbial population. This technology will be of potential significance to processors and consumers of tomatoes. A continuous antimicrobial treatment vessel was designed and fabricated to evaluate the effect of continuous treatment on removal of pathogens in fruits and vegetables. It is expected that the new system could more effectively reduce the bacterial loads in treated fruits and vegetables. Accomplishments 01 Use of nanoparticles to inactivate foodborne pathogens. Nanoparticles c be effective antimicrobial agents against foodborne pathogens. ARS researchers at Wyndmoor, PA, investigated the antimicrobial activities o two nanoparticles (magnesium oxide and zinc oxide) against three major foodborne pathogens: Escherichia coli O157, Salmonella Stanley, and Camplylobactor jejuni. The results demonstrated that these nanoparticle dramatically killed those pathogens and, therefore potentially can be added directly in foods or incorporated in packaging materials to improv microbiological safety. This research explores a new application of nan technology and inorganic antimicrobial compounds in the food safety area and provides useful information to the food and packaging industries. Th impact of nanopaticles on environment and human health is not clear. Currently nanotechnology is being evaluated in FDA�s Critical Path Initiative. Further toxicological studies are needed to determine the potential risks to human. 02 Determined irradiation conditions that eliminate pathogens without damaging spinach. Outbreaks of foodborne illness associated with leafy greens highlighted the safety concerns of the produce industry. Ionizin radiation is known to effectively eliminate human pathogens such as Escherichia coli O157:H7 on fresh produce. However, commercial application of irradiation is still limited partially due to concerns about possible damage to product quality. ARS researchers at Wyndmoor, P conducted a study to investigate quality of irradiated cut lettuce and spinach (salads) during storage at 4 degree C. Our results suggest that irradiation at doses up to 2 kilogray did not significantly affect overa antioxidant capacity, liking or consumers acceptance of spinach or appearance and texture of cut lettuce. The successful application of th FDA-approved technology on spinach will enable produce industry to reduc the risk of foodborne diseases in the U.S. The cost for commercial development of irradiated spinach is largely unknown and needs to be determined by the industry. 03 Combination of UV and irradiation improves microbial safety of tomatoes. Tomatoes are frequently consumed for their beneficial effect such as reducing risk of cancer and coronary heart disease in human population, but they can be contaminated with foodborne pathogens. ARS researchers Wyndomoor, PA, found that combined treatment with ultraviolet light and low-dose gamma irradiation can effectively reduce the population of E. coli O157:H7 on tomatoes, thus proving that this technology may be a suitable intervention approach to enhance microbial safety of tomatoes.
Impacts
(N/A)
Publications
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