Food Safety

How Clean Is Too Clean?


Have you ever heard the saying “God made dirt, so dirt don’t hurt”?  Wonder if that is a true statement or just something that some school children made up when they were throwing it at each other?  I believe there is some truth to this statement–

Being in the food industry we understand that listeria bacteria is widely found in soil *, it is part of our everyday environment, and even present around our own homes.  According to the FDA, humans and animals (wild and domesticated) can be carriers of listeria.  The bacterium often moves through the animal and human intestinal tract without causing illness, per the FDA website.

We also understand that the only way to guarantee the kill of listeria monocytogenes is to heat the food at the proper temperature for the proper amount of time (and that is located on packages of frozen food that is not considered RTE).   But have you ever thought about what is happening to your food supply and your overall immune system while we are trying to remove a pathogenic microorganism that we have lived with and around since birth?

According to research (good vs. bad germs, Healthline) our bodies need a certain amount of “good” bacteria found naturally in foods that help our health.  However, eliminating bad or pathogenic bacteria means we may not be exposed to the small doses that could inoculate us against intestinal crisis.—In other words we need to be able to fend off small doses of bad bacteria with our own immune systems.

The hygiene hypothesis is a theory that there may be a thing as food being “too clean”.  It believes that our modern-day life with antibacterial cleansers, vegetable washes and expectations of food processors to provide 0 listeria being present even in foods which are intended to be heated may be harming our microbiome, which are all the microscopic bacteria, viruses, and fungi that live in and on our bodies.  (Journal of Autoimmunity, Science Direct.)

Regarding food-borne illness, the idea is that fewer good bacteria in your gut means there is less competition to prevent colonization of the bad microbes, leading to more frequent bouts of illness.  The theory uses the approach that if you travel outside of the USA, where our food supply is second to none in regard to cleanliness, to a country with less stringent sanitation we all know who ends up being sick (and it is not the locals)!

Who suffers with this extremely clean food chain?  We all do!  Packing our bags for travel will require stomach medicine, worrying about how “clean” the food and water is, and losing the opportunity to taste street vendor food while being exposed to a new culture.  So the question will remain, How Clean Is Too Clean?

*sited from FDA website




ある研究(Good vs. Bad Germs, Healthline)によると、私たちの身体は、食品に自然に存在し健康維持に役立つ「善玉」バクテリアを一定量必要としています。しかし、「悪玉」バクテリア、すなわち病原菌を完全に取り除けば、腸の免疫力を支える効果のある微量のバクテリア接種の機会が失われてしまうかもしれません。つまり、微量の病原菌であれば身体の免疫系で防御できなければならないのです。

このため、食品が「清潔すぎる」ということもあるのではないかという理論が、衛生学の仮説となっています。この仮説では、私たちが現代生活で使用している殺菌消毒効果のある洗顔料や野菜の洗浄方法、さらには加熱調理して食べる食品ですらリステリア菌をゼロにしなければならないという食品加工業者への期待が、私たちのマイクロバイオームに害を及ぼしているかもしれないと考えています。マイクロバイオームとは、私たちの体内や皮膚の表面上に生息する微生物、バクテリア、ウイルス、菌類などの生態系です(Journal of Autoimmunity, Science Direct)。





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