What the hell is sour soup?

Sour soup, at first glance, may be thought to be sour soup. In fact, it is the staple food made of corn fermented by water mill, which is the yellow noodle-like food in the picture below. It tastes a little sour, smooth and refreshing, and it is very appetizing. The reason why few people know it is because sour soup is a regional food and a traditional special food that Manchu people often eat in summer. It is mainly popular in eastern Liaoning, southeastern Jilin and Heilongjiang.

The method of sour soup is very simple, that is, clean the broken corn, put it in a cool place, soak it in cold water for more than 10 days, and let it ferment naturally. If it smells sour, take it out and wash it, grind it into a paste with a water mill, control the appropriate amount of water with a cloth bag, and then put it in a cool environment or freeze it. When it is ready to eat, it will be squeezed into noodles and cooked in a pot. It is because of simplicity that many people in Northeast China will choose to make sour soup at home and then store it for eating.

There are three toxins to be mentioned here, 1 aflatoxin, 1 Staphylococcus aureus and 1 Aspergillus oryzae. Some foods will be moldy if they are not stored properly, and aflatoxin may be found in moldy foods, such as grains stored for too long. The raw material for making sour soup is corn kernels. If stored improperly, corn kernels will be contaminated with aflatoxin, which will lead to acid soup containing this toxin. However, aflatoxin poisoning is cumulative and will not happen immediately.

Speaking of Staphylococcus aureus, it often appears in starchy foods. If these foods are left at room temperature for more than 4 hours, they may produce this toxin. For example, in the process of making sour soup, if corn kernels are soaked at room temperature for more than 4 hours, there is a high probability that they will be contaminated by Staphylococcus aureus.