It is impossible to determine the presence or absence of food poisoning bacteria by smelling food

Many people have the experience of smelling fresh food such as meat and fish and trying to check whether it is safe when eating food stored in the refrigerator. However, Matthew Gilmore , who studies Listeria at the Quadrum Institute, points out that it is impossible to confirm the presence or absence of food poisoning bacteria by smell.

The sniff test is not reliable for food safety – here's why
https://theconversation.com/the-sniff-test-is-not-reliable-for-food-safety-heres-why-211808

Many food poisonings are caused by pathogens such as salmonella and norovirus. However, according to Mr. Gilmore, it is impossible to detect pathogens by smell.

Just as the yeast used to make bread gives off a pleasant aroma as it grows, some bacteria also give off odors. However, bacteria that cause food poisoning such as salmonella and listeria do not emit odors. In addition, Gilmore points out that salmonella is latent inside the food, so even if it is possible to smell the bacteria, it is impossible to detect salmonella.

On the other hand, the 'rotten smell' of ingredients can be easily sniffed out. As with fermented foods such as natto and cheese, a rotten smell does not necessarily mean that the food is unsafe. Still, Mr. Gilmore points out that it is ant to smell when checking the safety of ingredients such as vegetables and milk.

According to Mr. Gilmore, most food poisoning is caused by 'food with pathogens' rather than 'rotten food'. For this reason, Mr. Gilmore argues that measures such as ``storing at an appropriate temperature'' and ``heating for an appropriate time'' are more important than ``smelling'' in order to enjoy ingredients safely.

In addition, the Ministry of Health, Labor and Welfare lists three points as the principle of preventing bacterial food poisoning: ``Do not attach bacteria to food'', ``Do not increase bacteria attached to food'', and ``Defeat bacteria attached to food and cooking utensils''. . You can check the explanation of the food poisoning prevention method by the Ministry of Health, Labor and Welfare at the following link.

Food poisoning prevention at home | Ministry of Health, Labor and Welfare
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/shokuhin/syokuchu/01_00008.html