Homemade food, it's not easy to love you

With the changes and sedimentation of the times, in addition to pursuing high-end material enjoyment, some friends around us have begun to explore the small happiness of "doing it yourself to have enough food and clothing". For example, DIYing all kinds of food by yourself is one of their pleasures. For example, various homemade pickles, homemade fermented bean products, homemade sauces, homemade beverages, homemade snacks and cakes, homemade dried fruits, homemade wine, etc. are all objects that friends who are keen on homemade food like to explore. The finished products are not only enjoyed at home, but sometimes they are also brought to colleagues, relatives and friends, or sold on social platforms such as WeChat Moments. For friends who love homemade food, doing so can not only share the deliciousness with everyone, but also gain a great sense of accomplishment.

Image source: Tuchong Creative

However, homemade food is not just exquisite and beautiful as we see in the pictures on WeChat Moments. If you do not pay attention to food hygiene issues when making homemade food, it may cause various food safety risks. In fact, every year there are news reports of cases of homemade food causing poisoning or even death. For example, "A woman in Henan was poisoned by eating homemade stinky tofu and was admitted to the ICU", "A family in Heilongjiang was poisoned by eating homemade sour soup and 8 people died", etc. These shocking news are often caused by not paying attention to the hygiene and safety of homemade food. So today, let's take stock of the common risks of homemade food, and how to make and eat homemade food safely and healthily?

Homemade pickled/fermented foods

In traditional Chinese food culture, pickling/fermentation is an important way to extend the shelf life of food and preserve its flavor. In the era of food shortage, it solved the problem of food shortage in certain seasons. Nowadays, people no longer have to worry about food and clothing. Pickled and fermented foods are still popular on the Chinese table with their unique flavor, providing us with a variety of delicious foods.

The most common pickled foods that may be risky are homemade pickles and homemade pickled meats. The biggest problem with pickled vegetables is nitrite. Usually, leafy vegetables already contain nitrite. If the pickling time is too short, reducing bacteria will make the nitrite in the leafy vegetables higher. Eating a large amount of pickled vegetables at this time may cause nitrite poisoning, with dangerous symptoms such as chest tightness, difficulty breathing, dizziness, and palpitations. The safe way is to start eating after 14-21 days of pickling, so as to avoid the peak of nitrite production. A better way is to eat less or no pickled vegetables. If you must eat them, rinse them with running water several times to allow the nitrite to dissolve in the water and be taken away.

The risk of pickled meat is contamination by botulism. Once botulism is contaminated when handling pickled meat, it will multiply in an anaerobic environment (such as a sealed pickle jar) to produce botulinum toxin. This toxin is a dangerous neurotoxin, and in severe cases it can cause death due to respiratory and heart failure. In addition to pickled meat, botulism also likes to appear in fermented foods made from various soy products, such as sauces and stinky tofu. In the past few years, there have been reports from time to time that families in the Northeast have been poisoned by eating homemade bean paste and fermented black beans. This year, there have also been cases of women being poisoned by eating stinky tofu. To avoid botulism, on the one hand, you should pay attention to the hygiene of the production process when pickling and fermenting such foods; on the other hand, before eating such foods, you must fully heat and boil them for a certain time, such as more than 20 minutes, to ensure that the botulism is killed. In addition, pickled meat and fermented soy products should also be stored at low temperatures. Since low temperatures are not conducive to the reproduction of botulism, refrigeration is a good choice.

Recently, it is popular to pickle all kinds of seafood on the Internet, such as drunken shrimps and crabs. Usually, uncooked shrimps and crabs are pickled with white wine and various seasonings in order to retain the freshest taste and the most complete nutrients. However, uncooked shrimps and crabs are likely to contain microorganisms such as parasites, pathogens or viruses, which are difficult to kill completely even with high-proof white wine. What's more, the temperature and pickling time of homemade raw pickles are not accurate enough, and it is difficult to control the reproduction of bacteria and viruses. This is why there are often reports in the news about food poisoning caused by eating homemade raw pickles. I advise everyone to be cautious when eating raw pickled foods. If you are really greedy, buy big brand products from regular supermarkets to ensure that there are no food safety risks.

Homemade brewed water

Homemade wine was very popular in the past few years. For example, my aunt used to make homemade wine with grapes. However, the problem with homemade wine is that it is difficult to ensure sufficient fermentation due to the lack of professional guidance and regulation of temperature, humidity and time in the brewing process. Once the fermentation process is improper, a large amount of methanol is likely to be produced. Ingesting a large amount of homemade wine containing methanol may damage the central nervous system, cause blindness or even lose life. In addition, due to the lack of strict selection of brewing ingredients, residual pesticides and heavy metals are likely to be introduced at the raw material stage, which is particularly common in homemade medicinal wine.

In order to avoid the above risks, we sincerely recommend that you do not try to make your own wine. If you want to drink alcohol, choose the finished products of regular brands. If you want to drink something with fruit flavor, you can choose fruit tea.

Homemade yogurt

There are two common risks of homemade yogurt due to improper processing: one is that the yogurt is contaminated and multiplied by bacteria due to the lack of attention to hygiene during the production process, which causes gastrointestinal discomfort such as diarrhea after drinking. The other is that the homemade yogurt is spoiled due to being stored for too long (more than 3 days) or in improper storage conditions (not refrigerated).

Therefore, when making homemade yogurt, you should not only choose fresh pure milk, but also pay attention to the hygiene of hands and fermentation containers during the production process, and control the fermentation temperature between 40-45 degrees Celsius; the finished yogurt should be sealed in time, refrigerated, and eaten within 3 days. If you can pay attention to using a clean spoon every time you serve the yogurt, you can better avoid bacterial contamination.

Self-pressed edible oil

Home-made cooking oil is popular among many people because it contains no additives, has genuine ingredients and is rich in flavor. However, this seemingly safe and healthy cooking oil hides terrible risks.

Since home-made cooking oil cannot ensure the selection of raw materials, there is no processing procedure to remove toxins, and there is no supervision and constraints from relevant departments, once the raw materials (such as peanuts and other oil nuts) are contaminated by Aspergillus flavus, it may cause excessive aflatoxin in the squeezed oil. Long-term or frequent exposure to aflatoxin may cause serious liver damage and even liver cancer. Therefore, for home-made cooking oil, the best practice is not to buy or eat it, and directly refuse it. If you want to eat oil in a healthy way, you can buy finished and small-packaged cooking oil, and eat various oils such as peanut oil, rapeseed oil, soybean oil, olive oil, tea seed oil, flaxseed oil, etc., so as to obtain a variety of fatty acids and maximize health benefits.

We need to remind everyone that it is not recommended to buy or sell homemade food on online social platforms. On the one hand, due to the lack of relevant food safety laws and regulations, the health of the maker, the safety of the ingredients and processing process, and the quality of the finished product cannot be guaranteed like pre-packaged food sold in regular supermarkets. On the other hand, selling bulk or pre-packaged food requires certain qualifications. Selling without the corresponding qualifications is not legal and may cause trouble to the seller and the buyer.

The article is produced by Science Popularization China-Starry Sky Project (Creation and Cultivation). Please indicate the source when reprinting.

Author: Wang Lu, Chinese registered dietitian, Master of Public Health, Peking University

Reviewer: Xue Qingxin, the first batch of nutrition instructors of the National Health Commission, China registered nutritionist