76C-2 |
Growth/survival of E. coli O157:H7 on fresh-cut apples under modified atmospheres at abusive temperatures |
G. GUNES, Food Engineering Department, Istanbul Technical University, Istanbul Teknik Universitesi, Kimya-Metalurji Fakultesi, Gıda Muhendisligi Bl., Maslak-ISTANBUL, 80626, Turkey, J. H. Hotchkiss, Food Science, Cornell University, Stocking Hall, Ithaca, NY 14853, and C. B. Watkins, Department of Horticulture, Cornell University, Plant Science Building, Ithaca, NY 14853. E. coli O157:H7 has become a potential pathogen in fresh apple products. There is a great interest in fresh-cut apples in industry and market. Modified atmosphere (MA) storage under high CO2 low O2 has been shown to extend shelf-life of fresh-cut apples. However, the safety of the product in MA needs to be studied using the potential pathogen. Our objective was to determine effects of MA with high CO2 and abusive temperatures on growth/survival of E. coli O157:H7, yeast/mold count, and changes in quality in fresh-cut apples. Apple slices treated with an antibrowning agent were inoculated with the pathogen and stored under atmospheres with 0, 15, 30% CO2 with 1 or 21% O2 (balance N2) at 15 and 20 oC. E. coli O157:H7 and total yeast/mold were enumerated for15 days. Quality was assessed by sensory evaluations and a colormeter. MA with 30% CO2 prevented growth of the pathogen. Hovewer, the population of the pathogen increased by 1-log cycle after 2 wk storage in air. High CO2 concentration inhibited growth of the pathogen on apple slices at both low and ambient O2 concentrations. MA with high CO2 resulted in inhibition of yeast/mold growth and better visual quality than air and CO2-free atmospheres. High CO2 resulted in less browning and better sensory quality. The results suggest that E. coli O157:H7 can grow on apple slices in air, and survive in MA with high CO2 levels at abusive temperatures. High population of the pathogen did not affect the quality of the product. The MA can increase the shelf life of fresh-cut apples through retention of visual quality and inhibition of yeas/mold. Thus, contamination of slices with the pathogen can be a major safety issue, and an appropriate procedure along with MA to kill the bacteria is needed for safety assurance.
Session 76C, Fruit & Vegetable Product: Fresh Fruits and Vegetables
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