Salmon C P, Knize M G, Panteleakos F N, Wu R W, Nelson D O, Felton J S
Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, Livermore, CA 94550-9900, USA.
J Natl Cancer Inst. 2000 Nov 1;92(21):1773-8. doi: 10.1093/jnci/92.21.1773.
Heterocyclic amine carcinogens are formed during the cooking of a number of foods, especially well-done meats. Lower temperatures and shorter cooking times can minimize the formation of these carcinogens, yet a major food safety concern is that pathogens in the meat must be thermally inactivated. This study investigated cooking techniques that minimize heterocyclic amine formation while simultaneously destroying contaminating bacteria.
Ground beef patties were inoculated with Escherichia coli K12 bacteria and fried to internal temperatures ranging from 35 degrees C to 70 degrees C in a skillet preheated to 160 degrees C, 180 degrees C, or 200 degrees C. Each patty was then analyzed for four common heterocyclic amines and for surviving bacteria. Additionally, the frequency of turning of the beef patty during cooking was varied (a single turn or multiple turns), length of time required for each patty to reach 70 degrees C was recorded, and heterocyclic amine levels were determined. An additional pan temperature of 250 degrees C was tested for its effect on heterocyclic amine formation but not on bacterial killing. Statistical tests were two-sided.
Colony-forming bacteria were reduced by five orders of magnitude at internal temperatures greater than 60 degrees C, regardless of cooking method, and were completely inactivated at 70 degrees C. For patties turned just once, heterocyclic amine levels increased as the cooking temperatures increased. However, levels of heterocyclic amines were statistically significantly lower with turning every minute. For each pan temperature, patties reached 70 degrees C internal temperature sooner when they were turned every minute than when they were turned just once during cooking.
Lowering the pan temperature and turning the patties frequently can greatly reduce the formation of heterocyclic amines and can simultaneously achieve bacterial inactivation with little or no increase in cooking time, ensuring a product that is safe for human consumption.
多种食物烹饪过程中会形成杂环胺致癌物，尤其是熟透的肉类。较低的温度和较短的烹饪时间可使这些致癌物的形成量降至最低，但一个主要的食品安全问题是肉中的病原体必须通过加热灭活。本研究调查了能在使杂环胺形成量降至最低的同时，消灭污染细菌的烹饪技术。
将大肠杆菌K12接种到牛肉饼中，在预热至160℃、180℃或200℃的平底锅中煎至内部温度为35℃至70℃。然后对每个肉饼分析四种常见杂环胺及存活细菌。此外，改变烹饪过程中牛肉饼翻面的频率（单次翻面或多次翻面），记录每个肉饼达到70℃所需的时间，并测定杂环胺含量。还测试了250℃的额外锅温对杂环胺形成的影响，但未测试其对细菌杀灭的影响。统计检验采用双侧检验。
无论烹饪方法如何，内部温度高于60℃时，菌落形成细菌数量减少了五个数量级，在70℃时完全灭活。对于仅翻面一次的肉饼，杂环胺含量随烹饪温度升高而增加。然而，每分钟翻面时杂环胺含量在统计学上显著更低。对于每个锅温，肉饼在烹饪过程中每分钟翻面时比仅翻面一次能更快达到70℃的内部温度。
降低锅温并频繁翻面可大幅减少杂环胺的形成，同时能在烹饪时间几乎不增加或不增加的情况下实现细菌灭活，确保产品可供人类安全食用。
