Li Shuliu, Kundu Devapriya, Holley Richard A
Department of Food Science, University of Manitoba, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada.
Department of Food Science, University of Manitoba, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada.
Food Microbiol. 2015 Apr;46:34-39. doi: 10.1016/j.fm.2014.06.018. Epub 2014 Jun 26.
Lactic acid pre-treatment was examined to enhance the antimicrobial action of electron (e-) beam irradiation of beef trim. Meat samples were inoculated with Escherichia coli O157:H7, non-O157 VTEC E. coli or Salmonella cocktails and treated with 5% lactic acid at 55 °C. Samples were packaged aerobically or vacuum-packed, kept at 4 °C and treated with 1 kGy e-beam energy. Frozen samples were treated with 1, 3 or 7 kGy and stored at -20 °C for ≤ 5 d. Lactic acid enhanced the antimicrobial action of 1 kGy e-beam treatment against Salmonella by causing an additional <1.8 log CFU/g reduction. One kGy treatment of refrigerated samples reduced VTEC E. coli viability by 4.5 log CFU/g, and while lactic acid did not improve the reduction, after freezing additive effects were found. After 3 kGy irradiation, Salmonella was reduced by 2 and 4 log CFU/g in the irradiated and lactic acid plus irradiated samples, respectively. Lactic acid pre-treatment was of limited value with 1 kGy treatment for improving control of toxigenic E. coli in fresh beef trim, however, it would be useful with low dose irradiation for controlling both VTEC E. coli and Salmonella in frozen product.
研究了乳酸预处理对增强牛肉边角料电子（e-）束辐照抗菌作用的效果。将肉样接种大肠杆菌O157:H7、非O157型产志贺毒素大肠杆菌或沙门氏菌混合菌液，在55℃下用5%乳酸处理。样品进行有氧包装或真空包装，保存在4℃，并用1千戈瑞电子束能量进行处理。冷冻样品用1、3或7千戈瑞处理，并在-20℃下储存≤5天。乳酸通过额外降低<1.8个对数CFU/g，增强了1千戈瑞电子束处理对沙门氏菌的抗菌作用。1千戈瑞处理冷藏样品可使产志贺毒素大肠杆菌的活力降低4.5个对数CFU/g，虽然乳酸没有提高降低效果，但冷冻后发现有累加效应。3千戈瑞辐照后，辐照样品和乳酸加辐照样品中的沙门氏菌分别降低了2个和4个对数CFU/g。乳酸预处理对1千戈瑞处理改善鲜牛肉边角料中产毒素大肠杆菌的控制作用有限，然而，低剂量辐照对控制冷冻产品中的产志贺毒素大肠杆菌和沙门氏菌将是有用的。
