Nuts such as almonds and walnuts are rich in healthy fats and are considered good snacks for health.

If it is vacuum-sealed, one advantage is that the expiration date is about a year long. However, in hot and humid seasons like these, improper storage can lead to the formation of mold toxins, so caution is necessary.

Nuts are often considered to be non-perishable. However, if left at room temperature or exposed to direct sunlight, the fatty acids in nuts can oxidize and spoil, a process known as rancidity, or mold can develop. Mold produces toxins during its metabolic process, which are not destroyed during typical cooking or processing. Even in small amounts, these toxins can be harmful to the liver, kidneys, and other organs.

The main mycotoxins that can be found in nuts include aflatoxins, ochratoxins, and zearalenone. In particular, aflatoxins produced by rancidity and mold contamination can cause liver cancer and other diseases, and have been classified as Group 1 carcinogens by the International Agency for Research on Cancer. Aflatoxins grow best in hot and humid environments with temperatures above 25°C or relative humidity between 60-80%. Ochratoxins can cause chronic nephritis and acute fatty degeneration, while zearalenone can lead to reproductive disorders such as infertility.

To prevent nuts from going rancid, it is best to package them with a household vacuum sealer and store them in the refrigerator. If you do not have a vacuum sealer, simply put the nuts in a zipper bag and remove all the air. The important thing is to block out air and moisture. For nuts with shells, like peanuts, keep them in their shells and only take out the amount you plan to eat at once.

It is also important not to consume rancid nuts. Therefore, it is best to discard all nuts that have an unpleasant smell, such as paint-like odors. When purchasing nuts, carefully examine the exterior and other aspects, check the expiration date, and buy in small quantities. If there are white spots suspected to be mold or foreign objects, it is better to request a refund.