很多人认为冰箱能够通过低温杀死细菌。然而，这其实是一个常见的误解。普通家用冰箱的温度通常在4摄氏度左右，这个温度远远高于冰点，并不足以杀死细菌。
大多数病原细菌具有很强的温度适应能力。它们的最适生长温度通常是37摄氏度，也就是人体体温。但是，细菌能够在零度到60摄氏度的广泛温度范围内生存。这意味着冰箱的4度环境完全在细菌的生存范围内。
低温环境对细菌的主要作用不是杀死它们，而是减缓它们的生命活动。在低温下，细菌的新陈代谢会变慢，繁殖速度也会显著降低。这就是为什么冰箱能够延长食物保质期的原因。然而，需要强调的是，细菌并没有死亡，它们只是进入了一种相对静止的状态。
要真正杀死细菌，需要比冰箱温度高得多或低得多的极端温度。高温杀菌通常需要70到100摄氏度。巴氏杀菌法使用63摄氏度保持30分钟，或121摄氏度几秒钟。至于低温，普通冷冻温度负18摄氏度只能让细菌休眠，只有极低温度如液氮的负196摄氏度才可能对某些细菌造成致命伤害。
总结一下：冰箱并不会杀死细菌，它只是通过低温减缓细菌的生长和繁殖速度。细菌在冰箱中依然存活，当食物回到室温时，它们又会重新活跃起来。因此，我们需要采取其他食品安全措施，比如生熟食品分开存放，定期清洁冰箱，注意保质期，以及充分加热食物。记住，冰箱是保鲜工具，不是杀菌工具。
Most pathogenic bacteria have strong temperature adaptation abilities. Their optimal growth temperature is usually 37 degrees Celsius, which is human body temperature. However, bacteria can survive in a wide temperature range from 0 to 60 degrees Celsius. This means that the 4-degree environment of a refrigerator is completely within the survival range of bacteria.
The main effect of low temperature on bacteria is not to kill them, but to slow down their life activities. At low temperatures, bacterial metabolism slows down and reproduction rates decrease significantly. This is why refrigerators can extend food shelf life. However, it's important to emphasize that bacteria do not die - they just enter a relatively dormant state.
To actually kill bacteria requires much higher or much lower extreme temperatures than refrigerator temperature. Heat sterilization typically requires 70 to 100 degrees Celsius. Pasteurization uses 63 degrees Celsius for 30 minutes, or 121 degrees Celsius for several seconds. As for low temperatures, normal freezing temperature of minus 18 degrees Celsius only puts bacteria into dormancy. Only extremely low temperatures like liquid nitrogen at minus 196 degrees Celsius might cause lethal damage to some bacteria.