Yang Xianqin, Devos Julia, Klassen Mark D
1 Agriculture and Agri-Food Canada Lacombe Research and Development Centre, 6000 C&E Trail, Lacombe, Alberta, Canada T4L 1W1.
2 Canadian Cattlemen's Association, #180, 6815-8th Street N.E., Calgary, Alberta, Canada T2E 7H7.
J Food Prot. 2017 Oct;80(10):1641-1647. doi: 10.4315/0362-028X.JFP-17-081.
A national survey was conducted in Canada to determine consumer cooking practices for minute steaks (thin, mechanically tenderized beef cutlets). Results indicate that most Canadians prefer cooking minute steaks by pan frying and to a medium level of doneness. To identify safe cooking conditions, retail minute steaks (∼125 g), inoculated at three sites per steak with a five-strain cocktail of nontoxigenic Escherichia coli O157:H7 (6.1 log CFU per site), were cooked on a hot plate (200°C), mimicking a pan-frying scenario. The steaks (n = 5) were cooked for 4, 6, 8, or 10 min with turning over (flipping) up to four times at equal time intervals; or to 63 or 71°C at the thickest area with or without a tinfoil lid. When cooked for 4 min, E. coli O157:H7 was recovered from all inoculation sites, and the mean reductions at various sites (1.2 to 3.4 log CFU per site) were not different (P > 0.05), irrespective of the flipping frequency. When cooked for 6 min with flipping once or twice, or for 8 min with flipping once, E. coli O157:H7 was recovered from most sites; the mean reductions (3.8 to 5.3 log CFU per site) were not different (P > 0.05), but they were higher (P < 0.05) than those for steaks cooked for 4 min. When cooked for 10, 8, or 6 min with flipping once, twice, or three times, respectively, E. coli O157:H7 was eliminated from most sites, but sites with <5-log reductions were found. Reductions of E. coli O157:H7 by >5 log at all inoculation sites were attained when the steaks were cooked for 10 or 8 min with two or more or three or more flippings, respectively, or for 6 min with four flippings. When flipped twice during cooking to 63 or 71°C, E. coli O157:H7 was recovered from three or fewer sites; however, >5-log reductions throughout the steaks were only attained for the latter temperature, irrespective of whether the hot plate was covered with the tinfoil lid. Thus, turning over minute steaks twice during cooking to 71°C or flipping two, three, or four times with a cooking time of 10, 8, or 6 min could achieve 5-log reductions throughout the steaks.
在加拿大开展了一项全国性调查，以确定消费者烹饪嫩牛排（薄的、经过机械嫩化的牛肉排）的习惯。结果表明，大多数加拿大人更喜欢用平底锅煎的方式烹饪嫩牛排，且喜欢煎至中等熟度。为确定安全的烹饪条件，将零售嫩牛排（约125克），每块牛排的三个部位接种由五株非产毒大肠杆菌O157:H7组成的菌悬液（每个部位6.1 log CFU），在模拟平底锅煎的热板（200°C）上进行烹饪。这些牛排（n = 5）分别烹饪4、6、8或10分钟，每隔相等时间间隔翻面（翻转）最多四次；或者在最厚部位烹饪至63或71°C，有或没有锡纸覆盖。烹饪4分钟时，所有接种部位均能检出大肠杆菌O157:H7，各部位的平均菌数减少量（每个部位1.2至3.4 log CFU）无差异（P > 0.05），与翻转频率无关。烹饪6分钟且翻转一或两次，或烹饪8分钟且翻转一次时，大多数部位能检出大肠杆菌O157:H7；平均菌数减少量（每个部位3.8至5.3 log CFU）无差异（P > 0.05），但高于烹饪4分钟的牛排（P < 0.05）。分别烹饪10、8或6分钟且翻转一、二或三次时，大多数部位的大肠杆菌O157:H7被消除，但仍发现有菌数减少量小于5 log的部位。当牛排分别烹饪10分钟且翻转两次或更多次、8分钟且翻转三次或更多次、6分钟且翻转四次时，所有接种部位的大肠杆菌O157:H7菌数减少量均大于5 log。烹饪至63或71°C过程中翻转两次时，三个或更少部位能检出大肠杆菌O157:H7；然而，仅在后者温度下，无论热板是否用锡纸覆盖，整块牛排的菌数减少量均能达到大于5 log。因此，烹饪嫩牛排至71°C过程中翻转两次，或烹饪10、8或6分钟时翻转两、三或四次，可使整块牛排的菌数减少5 log。
