30G-15 |
Presence and growth of microorganisms in Iowa apple cider |
P. DEOL, B. A. Glatz, and L. A. Wilson. Dept. of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011 Recent outbreaks of illness caused by E.coli O157:H7 in unpasteurized apple cider have prompted FDA regulations requiring processing techniques to ensure a 5-log reduction in targeted pathogens or the application of a warning label on unprocessed cider. Limited information is available on contamination levels in apples, freshly produced cider and stored cider. This project determined microbial contamination of apples and apple cider produced in Iowa and followed changes in organisms during cider storage. Apples and cider from 3 cider production facilities were subjected to standard enumeration methods for aerobic bacteria, yeasts and molds, coliforms and E. coli. Cider samples were stored for 6 to 8 weeks at 4°C; microbial counts were obtained at regular intervals. Microbial counts on apples ranged from 103 to 107 per apple for aerobic bacteria, yeasts and molds. Washing apples with poor quality water increased microbial loads by 100 fold. Counts on apples were 100-1000 times higher in 2001 than in 2000. Counts for aerobes, yeasts and molds in raw cider ranged from 102 to 105 cfu/ml while in pasteurized cider these were <10 cfu/ml. Coliform counts in raw cider ranged from 1 to 100 cfu/ml; in pasteurized cider coliforms were below detection limits. E.coli were also below detection limits (10 cfu/ml) in both raw and pasteurized cider. Use of an enclosed bottling system significantly reduced counts in fresh cider. Microbial loads in pasteurized cider increased from <10 cfu/ml to >106 cfu/ml over 6 weeks of storage; counts in raw cider reached 106 cfu/ml levels in 4 weeks. Pasteurization is an effective way to reduce microbial loads in cider. However, during storage, heat-injured microorganisms can recover and increase rapidly in number. Proper handling is required to maintain cider safety and quality.
Session 30G, Fruit & Vegetable Product: Processed Fruits and Vegetables
|