As a master of cooking in the family, Aunt Li specially prepared a good dish this time - the family heirloom sauerkraut fish, accompanied by the pickled cabbage by herself, the sour aroma came to her nose.
Just as everyone was praising each other, Aunt Li's niece Xiao Lin raised her concerns: "Auntie, I recently learned that homemade fermented foods may have health risks if they are not properly made. Like nitrite levels, you know?"
Aunt Li smiled, a trace of doubt flashed in her eyes, but she couldn't hide her thirst for knowledge: "Xiaolin, tell me, what the hell is going on?"
Kobayashi patiently explained: "Actually, fermentation is a double-edged sword. It creates a unique flavor and enhances the nutritional value of food, which can be problematic if the fermentation conditions are not well controlled. Causes a toxic reaction.
01. What is fermented food and what are the fermented foods
Fermented food refers to a series of complex biochemical changes in food raw materials by using the growth of beneficial microorganisms such as yeast, bacteria and molds and their enzymatic actions.
This process not only changes the flavor and texture of the food, but also often enhances the nutritional value of the food and produces some active substances that are beneficial to the human body.
Fermented legumes: Soybeans are fermented to develop unique flavor and functional components. Such foods include soy sauce, tempeh, bean paste, tofu, etc.
During the fermentation process, the anti-nutritional factors in soybeans are reduced, and soybean polypeptides, soy isoflavones, etc., are produced at the same time, which have antioxidant, pro-digestion and potential anti-cancer effects.
Fermented milk: Through the action of microorganisms such as lactic acid bacteria, milk or other dairy products are transformed into foods with a sour taste, such as yogurt, kefir, yoghurt, etc. These foods help to improve gut health and boost immunity.
Fermented meat: Fermented meat products such as hams and sausages are fermented by specific microorganisms, which not only extends the shelf life but also adds flavor. The beneficial microbial community created during fermentation helps to inhibit the growth of harmful bacteria.
Fermented cereals: This includes a variety of alcoholic beverages such as beer, rice wine, liquor, and non-alcoholic vinegar. Through fermentation, the starches and sugars in the grains are converted into alcohol or acids, while developing a unique flavor and nutritional value.
Fermented vegetables, such as kimchi, sauerkraut, German sauerkraut, etc., produce lactic acid through lactic acid bacteria fermentation, which not only preserves the vegetables, but also gives them a unique sour taste, and also improves the bioavailability of vitamins and minerals.
Fermented tea: For example, black tea, black tea, oolong tea, etc., the tea leaves are oxidized or partially fermented by microorganisms to form different colors, aromas and health care functions.
02. Safety of fermented foods
Raw material safety: The safety of fermented foods depends first and foremost on the quality of the raw materials. Contaminants present in raw materials, such as pesticide residues, heavy metals, mycotoxins, etc.
It may be concentrated or transformed during fermentation, affecting the safety of the final product. Therefore, screening and cleaning of raw materials prior to fermentation is crucial.
Microbial contamination: The fermentation process relies on the activity of specific microorganisms, but contamination by non-target microorganisms can lead to food safety issues.
Contamination of fermented cereals and potatoes, soaked fungus and white fungus by Pseudomonas coconut can produce lethal oryza fermented acid, which cannot be removed even when cooked at high temperatures, posing a serious health threat.
Contamination by bacteria during natural fermentation, such as Serratia marcescens and Bacillus subtilis, may change the colour, smell and even produce harmful substances.
Nitrite problems: Homemade fermented vegetables, especially in the early stages of pickling, can cause nitrite levels to rise to concentrations that can be harmful to health. Proper control of fermentation time and conditions, and avoiding consumption during peak nitrite periods, is key to preventing poisoning.
Fermentation process control: Fermentation conditions, including temperature, humidity, pH, etc., must be strictly controlled to promote the growth of beneficial microorganisms while inhibiting harmful microorganisms. Improper fermentation management can lead to problems such as the accumulation of biogenic amines, abnormal alcohol levels, and the formation of harmful by-products.
Selection of fermentation strains: The microbial strains used for fermentation need to undergo strict screening and safety evaluation to ensure that they do not produce harmful metabolites and do not carry drug resistance genes to ensure food safety and consumer health.
Homemade risks: Homemade fermented foods lack strict monitoring in industrial production, and are more susceptible to environmental pollution, improper operation and other factors, thus increasing safety risks.
Regulations and standards: Following national or regional food safety regulations and standards, such as the corporate standard Q/ZTS 0001 S-2022 for fermented flour products, is essential to ensure the safety of fermented foods.
03. Soaking fungus and white fungus are susceptible to contamination
Soaked fungus and white fungus are susceptible to contamination with Pseudomonas coconut, a serious problem that can cause food poisoning.
Under certain conditions, Pseudomonas coconut is able to produce a toxin called rice fermented acid, which is extremely heat-resistant and difficult to destroy even after high-temperature cooking, thus potentially retaining its toxicity and posing a threat to the consumer.
Suitable environment: Pseudomonas coconut multiplies rapidly in warm and humid environments, and the process of soaking fungus and white fungus provides such environmental conditions, especially in summer or warm and humid climates.
Prolonged soaking: Prolonged soaking increases the risk of contamination of fungus and tremella fungus, as this gives the bacteria ample time to grow and produce toxins. This problem is further exacerbated by improper storage conditions, such as not refrigerating or leaving at room temperature overnight after soaking.
Improper cleaning: If not thoroughly cleaned before soaking, bacteria that may be carried on the surface of fungus and tremella can multiply rapidly during the soaking process.
Precautionary measures: In order to ensure safety, it is recommended to wash the fungus and white fungus thoroughly before soaking, use a clean container and water for soaking, and consume it as soon as possible after soaking. If it needs to be delayed, it should be stored in the refrigerator and avoid prolonged storage at room temperature.
Timely identification of deterioration: Spoiled fungus or white fungus may have a peculiar smell or different color, once such a situation is found, it should be discarded immediately and should not be edible.
While we pursue good food, we should pay more attention to the dual protection of health and safety. As a food art intertwined with tradition and modernity, fermented food not only carries the charm of history, but also is an indispensable health element in modern life.
Behind every delicious meal, there is a hidden test of food safety. The warning that soaked fungus and white fungus are susceptible to Pseudomonas coconut contamination is a wake-up call that we should not ignore the potential health threats while enjoying the gifts of nature.
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