Most people on the road to health should have encountered the saying that “it is not suitable for × × × after a meal”, such as not eating fruit, not lying down, not taking a bath after a meal…
Actually, it’s the worst thing to do after a meal, but what most people do is–Wait for the leftovers to cool down completely before putting them in the fridge .
Honestly, putting food that is still hot in the refrigerator is indeed a “mummy fight” behavior, but leaving leftovers at room temperature is a very unhealthy operation .
(Source: giphy)
The U.S. Food and Drug Administration (FDA) states that at room temperature, the number of bacteria in food that can cause foodborne illness doubles every 20 minutes[1].
While the meal is cooling, not only may bacteria from the surrounding environment fall into the meal, but “indigenous” bacteria in the meal may also “die to death” when they reach the right temperature. resurrection”.
For example, “Bacillus cereus”, which is often attached to rice, is a bacterium that can cause food poisoning, and most of the food it contaminates is not obvious The phenomenon of corruption, deterioration and odor [2].
The “Spore” in its name is equivalent to the “Dormant Pod” in the sci-fi movie. Once it is heated, refrigerated, etc. It can enter a dormant state immediately when the factors suitable for survival are present. But once the food returns to room temperature, it’s a “hero” again “out of the cabin”.
Many parents are not used to putting hot dishes directly in the refrigerator because food that is afraid of heat will damage the refrigerator or increase the power consumption of the refrigerator.
Actually, there is no need to think of refrigerators as fragile.
(Source: giphy)
The current refrigerator has a large capacity and cools quickly. As long as you don’t put a large pot of hot water that has just boiled, it can hold up.
A plate or two of leftover hot dishes is not enough to affect the overall temperature in the refrigerator for long. If the food is too hot, you can cool it in water or divide it into small portions before putting it in.
The most important thing is that even if there are temperature changes in the refrigerator, the electricity bill is not as high as expected.
A study by China Institute of Jiliang shows [3]: The internal temperature of the refrigerator is 2°C higher than the set temperature, and the extra power consumed in one day is about 0.04 degrees .
(Source: Internet)
Not to mention, leftovers won’t last a day in the fridge. In this way, the increase in electricity bills for a month is definitely not as high as the registration fee for food poisoning.
As for problems like frosting, it’s also easy to solve. Seal the leftovers with plastic wrap to reduce evaporation.
Although the long-term low temperature environment of the refrigerator can restrain the reproduction speed of microorganisms such as bacteria and fungi, it is not omnipotent and cannot create a sterile environment [4].
The image below is a report from the Guangdong Provincial Institute of Microbiology of fungi scanned from household refrigerators:
(Image source: Energy consumption analysis and test system design of household refrigerators [4] )
The report pointed out that the above pathogenic bacteria can cause a wide range of diseases, not only limited to the digestive system, but also to the respiratory system, urinary system, blood system, skin, muscle and other diseases. Such as various types of tinea, cystitis, sepsis, etc. [4].
Unwashed raw food, damaged food packaging, and hands handling food can all bring these pathogenic bacteria into the refrigerator, which can cause food contamination in the air-conditioning cycle [5] .
So,In addition to paying attention to the storage method of leftovers, you must also pay attention to the heat before eating!
For example, when heating meals in the microwave, make sure the entire serving is fully heated. Every “cold dead corner” that is not taken care of by microwaves may have pathogenic bacteria that are ready to invade the intestinal tract at any time.
According to statistics, more than half of food poisoning incidents in my country occur in families, and 30% to 40% are caused by “improper food handling” [6].
In all aspects of household food processing, “leftovers disposal” is precisely the weakest link[7]. The following flow chart summarizes the shortcomings of food handling in the home.
The disposal of leftovers is the last step. The problems and microorganisms that were missed in the previous steps may all explode in this step.
(Source: China Population, Resources and Environment[8])
So, in addition to reducing the storage time at room temperature, I hope you can keep these 3 points in mind:
1. Leftovers should be refrigerated in a covered container or plastic wrap.
Refrigerators not only fail to create a sterile environment, they also create an excellent environment for cross-contamination.
2. Leftovers should not be refrigerated for more than 3 days.
Remember the nitrites in the leftovers? According to research, the nitrite content of most of the dishes stored in the refrigerator will increase sharply from the 4th day [9].
3. Do not reheat leftovers.
The act of repeated heating also increases nitrite levels dramatically [10]. If you can’t eat it after heating it once, please throw it away~
Reviewer: Pingping Liu| Registered Dietitian
References
[1]https:https://www.fda.gov/food/buy-store-serve-safe-food/refrigerator-thermometers-cold-facts-about-food-safety
[2] Li Fengyuan. An investigation of food poisoning caused by Bacillus cereus [J]. Medical Animal Control, 2015,31(04):455-456.
[3] Liu Jun. Energy consumption analysis and test system design of household refrigerators [D]. China Institute of Jiliang, 2014.
[4] Yang Songzhen, Feng Guangda, Yao Qing, Wang Yonghong, Yao Yuxin, Zhu Honghui. Investigation of microbial species in household refrigerators [J]. Biotechnology Bulletin, 2013(02):195 -200.
[5] Michaels B, Ayers T, Celis M, et al. Inactivation of biorefrigeratorfilm bacteria for application in the food service environment［J］． Food Service Technology, 2001, 1(3): 169-179.
[6]Li Bai,Jin Tang,Yinsheng Yang,Shunlong Gong. Hygienic food handling intention. An application of the Theory of Planned Behavior in the Chinese cultural context[J]. Food Control, 2014, 42.
[7] Zhang Xiaolin. Research on food handling risk behavior and influencing factors in family environment [D]. Shanxi Medical University, 2019.
[8] Lu Jiao, Wang Xiaoli, Wu Linhai, Shan Lijie. Study on the correlation between household food handling risk behavior characteristics and foodborne diseases [J]. China’s Population, Resources and Environment ,2017,27(08):98-105.
[9] Liu Binghua, Ma Xupan, Pu Xiaolong, Tao Xuemei, Yang Lin. Effects of disposal methods on nitrite content in dishes [J]. Food Research and Development, 2014, 25( 12):5-8.
[10] Mo Baoqing, Zhou Jingping, Zhou Ming. Effects of repeated heating and storage on the nutritional and hygienic quality of fried vegetables [J]. China Journal of Hygiene Inspection, 2015, 25(06): 810-812+815.
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