Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2007
Publication Date: 6/1/2007
Citation: Juneja, V.K., Bari, L.M., Inatsu, Y., Kawamoto, S., Friedman, M. 2007. Control of Clostridium perfringens Spores by Green Tea Leaf Extracts During Cooling of Cooked Ground Beef, Chicken, and Pork. Journal of Food Protection. 70(6):1429-1433. Interpretive Summary: One of the most common types of food poisoning in the United States is caused by the bacterium, Clostridium perfringens. Illnesses have been traditionally associated with inadequate cooling practices in retail food service operations. Thus, there was a need to determine the cooling time and temperature for cooked beef, chicken, or pork products to remain pathogen-free and provide vital data for performing risk assessment on cooked meat. We determined that cooling times for ground beef, chicken, and pork after heat processing can be extended to 21 h by incorporation of green tea extract (697 mg total catechins/g of extract) at 2% level to reduce the potential risk of C. perfringens germination and outgrowth. These findings will be of immediate use to the retail food service operations and regulatory agencies to ensure the safety of the cooked foods.
Technical Abstract: We investigated the inhibition of Clostridium perfringens spore germination and outgrowth by two green tea extracts with low (GTL; 141 mg total catechins/g of green tea extract) and high (GTE; 697 mg total catechins/g of extract) catechin levels during abusive chilling of retail cooked ground beef, chicken, or pork. Green tea extracts were mixed into the thawed beef, chicken or pork at concentrations of 0.5, 1.0 or 2.0% (w/w) along with a heat-activated (75C/20 min) three-strain spore cocktail to obtain a final concentration of about 3 log10 spores/g. Samples (5 gm) of the ground beef, chicken or pork were then vacuum-packaged and cooked to 71C in 1 h in a temperature-controlled water bath. Thereafter, the products were cooled from 54.4C to 7.2C in 12, 15, 18 or 21 h, resulting in significant increases (p< 0.05) in germination and outgrowth of C. perfringens populations in the ground beef, chicken, or pork control samples without GTL or GTE. Supplementation with 0.5 to 2% levels of GTL did not inhibit C. perfringens growth from spores. In contrast, addition of 0.5 to 2% levels of GTE to beef, chicken or pork resulted in concentration- and time-dependent inhibition of C. perfringens growth from spores. At 2% GTE, significant (p < 0.05) inhibition of growth occurred at all chill rates for cooked ground beef, chicken, or pork. These results suggest that widely consumed catechins from green tea can reduce the potential risk of C. perfringens spore germination and outgrowth during abusive cooling from 54.4C to 7.2C in 12, 15, 18, or 21 h of ground beef, chicken, or pork.