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United States Department of Agriculture

Agricultural Research Service

2011 Annual Report

1a.Objectives (from AD-416)
Determine sensory, nutritional and/or product quality impacts of efficacious food processing interventions and combinations of interventions.

Identify compounds of potential concern formed by novel non-thermal food processing interventions.

Develop/optimize treatment processes and combinations to control pathogens and to minimize loss of product quality and value.

Develop antimicrobial packaging-based treatments for controlling pathogens.

1b.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. After evaluation and modification of current antimicrobial treatments and processes, intervention technologies and process that have been demonstrated to be effective in inactivating human pathogens will be optimized to obtain a minimum 3 log CFU/g reduction of E. coli O157:H7 and Salmonella on leafy green vegetables, tomatoes and other RTE foods. Novel intervention technologies will also be explored and evaluated. The impact of efficacious chemical and physical intervention technologies on sensory properties, nutrients, and shelf-life will be evaluated using the intensity (time, concentration, dose etc.) that achieves the same (3 log CFU/g) reduction of the pathogens. In addition, new formula will be developed to minimize risk of pathogen contamination during treatment while inhibiting tissue browning of cut produce. 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 to reduce or control the re-growth of surviving pathogens during storage. Finally, combinations of various intervention technologies with antimicrobial packaging will be evaluated for additive or synergistic inhibition of pathogens and preservation of product quality. Developing and modifying treatment conditions to minimize adverse effects of intervention technologies will be a focus in the later period of the project.

3.Progress Report
A study was conducted to investigate the effect of modified atmosphere packaging (MAP) and delay of irradiation application on the quality of cut Iceberg lettuce. Results showed that irradiation (0.5 and 1.0 kilogray) of cut lettuce induced tissue browning when stored in air; however, when cut-lettuce was stored in MAP, irradiated lettuce had better appearance than the non-irradiated ones due to lower oxygen levels in the packages of irradiated samples compared to the levels in control packages. The results suggest that MAP is essential to minimize quality deterioration caused by irradiation.

1. New technology for safer liquid eggs. Salmonella is the leading cause of egg-related food borne illnesses and poses serious health threat to consumers. Liquid eggs are therefore pasteurized to eliminate Salmonella. However, the functional properties of liquid eggs are impaired by thermal pasteurization. ARS researchers at Wyndmoor, PA, developed a membrane-based process to eliminate Salmonella completely from commercial unpasteurized liquid egg white without affecting egg white protein’s functional quality. Successful commercialization of the technology will enhance microbial safety of liquid eggs.

2. Minimizing quality loss of leafy greens by irradiation. Recent outbreaks of foodborne illness associated with leafy greens highlighted the safety concerns of the produce industry. Ionizing 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, PA, conducted a study to investigate the quality of irradiated cut lettuce and spinach (salads) during storage at 4 C. Our results suggest that irradiation at doses up to 2 kilogray did not significantly affect overall antioxidant capacity, liking or consumers acceptance of spinach or appearance and texture of cut lettuce. The successful application of this FDA-approved technology on lettuce and spinach will enable the produce industry to consider irradiation as an intervention technology and reduce the risk of foodborne diseases in the U.S.

Review Publications
Mukhopadhyay, S., Onwulata, C.I., Yadav, M.P., Thomas-Gahring, A.E., Tunick, M.H. 2011. Thermophysical properties of starch and whey protein composite prepared in presence of organic acid and esters. Journal of Biobased Materials and Bioenergy. 5:10-8.

Jin, Z.T., Gurtler, J. 2010. Inactivation of Salmonellae in liquid egg white by antimicrobial bottle coating with allvl isothiocyanate, nisin and ZnO nanoparticles. Applied and Environmental Microbiology. 110(3):704-712.

Sampedro, F., Rodrigo, D., Fan, X. 2010. High hydrostatic pressure processing of fruit juices and smoothies: research and commercial application. In: Doona,C., Kusting, K., Feeherry, F., editors. Case studies in novel food processing technologies. Cambridge, UK: Woodhead Publishing. p. 34-72.

Guan, W., Huang, L., Fan, X. 2010. Acids in combination with sodium dodecyl sulfate caused quality deterioration of fresh-cut iceburg lettuce during storage in modified atmosphere package. Journal of Food Science. 75:S435-S440.

Fan, X., Sokorai, K.J. 2011. Effects of gamma irradiation, modified atmosphere packaging and delay of irradiation on quality of fresh-cut iceberg letuce. HortScience. 46:273-277.

Jin, Z.T., Niemira, B.A. 2011. Application of polylactic acid coating with antimicrobials in reduction of Escherichia coli O157:H7 and Salmonella stanley on apples. Journal of Food Science. 76(3):184-188.

Fan, X., Sokorai, K.J. 2011. Changes in quality, liking and purchase intent of irradiated fresh-cut spinach during storage. Journal of Food Science. 76(6):353-368.

Fan, X. 2010. Commercialization of irradiation on fresh fruits and vegetables. In: Doona, C., Kustin, K, Feeherry, F., editors. Case studies in novel food processing technologies. Cambridge, UK: Woodhead Publishing. p. 427-446.

Mukhopadhyay, S., Tomasula, P.M., Luchansky, J.B., Porto Fett, A.C., Call, J.E. 2011. Removal of Bacillus anthracis sterne spore from commercial unpasteurized liquid egg white using crossflow microfiltration. Journal of Food Processing and Preservation. 35:550-562.

Mukhopadhyay, S., Tomasula, P.M., Luchansky, J.B., Porto Fett, A.C., Call, J.E. 2010. Removal of Salmonella Enteritidis from commercial† unpasteurized liquid egg white using pilot scale crossflow tangential microfiltration. Internationl Journal of Microbiology. DOI: 10.1016/j.ijfoodmicro.2010.07.009.

Last Modified: 10/7/2015
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