2007 Annual Report
Analysis of fresh-cut preparation methods for potential microbial contamination. Coring iceberg lettuce in the field is a new technology that has significantly improved the production yield and reduced shipping cost. However, no scientific studies have been reported on the potential of E.coli O157:H7 contamination during field procedures and the effect of field conditions on the survival and growth of E.coli O157:H7 on pre-cored lettuce. We evaluated the potential for pathogen transfer during coring process and demonstrated that E.coli O157:H7 can be readily transferred from contaminated coring knives to the edible portion of lettuce; also, a 4-hour exposure of cored lettuce to 30 °C ambient environment significantly increased E.coli populations on lettuce. Our results provide critical information for the development and implementation of Good Agricultural Practice (GAP) and Hazardous Analysis and Critical Control Point (HACCP) by the FDA and produce industry.
The control of the growth of disease-causing microorganisms and the enzymatic browning reaction on the cut-surface of apple slices is critical to maintaining the safety and quality of fresh-cut produce. We demonstrated and optimized the utility of a chemical compound, sodium chlorite, that has the potential to control both the browning reaction and pathogen growth for a variety of fresh-cut produce, including apples, pears, and lettuce, etc. This information is very useful for the development of dual control agents and to solve the current challenges facing the industry due to the incompatibility between browning inhibitors (reducing agents) and most sanitizers (oxidants) used commercially. We also found that an ultra sound technology significantly improved the efficacy of various sanitizers, including chlorine and acidified sodium chlorite, on pathogen reduction on spinach. Both the consumers and fresh-cut produce industry will benefit from the results of this research. This research fulfills a top ARS food safety research priority requested by the produce industry. This research is under National Program 108, Section 2.4.1.
Zhang, Y., Emily, Y., Cripe, J., Hall, G., Bhagwat, A.A., Meng, J. 2007. Characterization of listeria monocytogenes isolated from retail food. International Journal of Food Microbiology. 113:47-53.
Sharma, M., Kniel, K., Derevianko, A., Ling, J., Bhagwat, A.A. 2007. Sensitivity of Escherichia albertii, a potential foodborne pathogen, to food preservation treatments. Applied and Environmental Microbiology. 73(13):4351-4353.
Wang, H., Feng, H., Luo, Y. 2006. The effect of acidic electrolyzed water and peroxyacetic acid on reduction of escherichia coli o157:h7 populations on fresh-cut apples. Journal of Food Safety. 26:335-347.
Wang, H., Feng, H., Luo, Y. 2007. Control of browning and microbial growth on fresh-cut apples by sequential treatment of sanitizers and calcium ascorbate. Journal of Food Science. 72:M1-M7.
Kim, J., Lim, C., Luo, Y. 2007. Effect of ozonated water and chlorine water wash on the quality and microbial de-contamination of fresh-cut carrot shreds. Korean Journal of Food Preservation. 14(1):54-60.
Lu, S., Luo, Y., Turner, E.R., Feng, H. 2007. Efficacy of sodium chlorite as an inhibitor of enzymatic browning in apple slices. Journal of Food Chemistry. 104:824-829.
Zhu, B., Lu, J., Luo, Y., Tao, Y. 2007. Gabor feature-based apple quality inspection using kernel principal component analysis. Journal of Food Engineering. 81(4):741-749.
Ruiz-Cruz, S., Luo, Y., Gonzalez, R., Tao, Y., Gonzalez, G. 2006. Effect of acidified sodium chlorite applications on microbial growth and the quality of shredded carrots. Journal of the Science of Food and Agriculture. 86(12):188-1893.