Knowledge Point 01: Canned Food Remains Fresh Due to Its Sealed Sterile Environment
Canned food, such as lunch meat, canned dace with black beans in tomato sauce, and baked beans, undergoes special processing.
During production, manufacturers remove all air from the cans and immediately seal them. This sealed environment effectively isolates the food from external bacteria and air, allowing it to be preserved in a sterile state.
In the absence of oxygen and bacteria, even if a small amount of bacteria adheres to the food surface, it cannot survive or reproduce, thus ensuring long-term preservation and stable quality of the food.
Knowledge Point 02: Rancid Food Produces Toxic Substances Due to Fatty Acid Decomposition
The rancid odor produced during food spoilage is the specific smell of ketones and aldehydes, which are the products of fatty acid decomposition. Consuming such food may lead to poisoning.
Food spoilage is a complex process involving the decomposition of proteins, carbohydrates, and fats in food. Among them, fat spoilage is mainly due to rancidity. When neutral fats in food decompose under the action of enzymes produced by microorganisms, ultraviolet light, and oxygen, they generate glycerol and fatty acids.
These fatty acids further decompose into peroxides and oxides, which then produce ketones and aldehydes with a specific pungent odor, known as the rancid odor. Consuming food that has been stored for too long and developed a rancid odor may cause poisoning, with clinical symptoms mainly involving gastrointestinal disturbances such as dizziness, headache, abdominal bloating, diarrhea, abdominal pain, nausea, and vomiting.
Knowledge Point 03: Consuming Vitamin C with Seafood May Produce Harmful Substances
Due to its reducing properties, vitamin C may undergo chemical reactions when consumed with seafood, generating harmful substances. Therefore, it is not recommended to consume them simultaneously.
Vitamin C is a nutrient with strong reducing properties, while seafood often contains a certain amount of pentavalent arsenic compounds. When vitamin C is consumed with seafood, the reducing property of vitamin C may reduce pentavalent arsenic to trivalent arsenic, which is the main component of arsenic trioxide (white arsenic).
Although the amount of arsenic trioxide produced by this chemical reaction in daily diet is usually not enough to cause severe poisoning, long-term or excessive simultaneous consumption may still have adverse effects on health.
Therefore, to avoid potential health risks, it is recommended not to consume vitamin C and seafood at the same time.
Knowledge Point 04: Sausages, Salted Meat, and Other Foods Containing Sodium Nitrite Can Generate Carcinogenic Substances
Sodium nitrite present in sausages, salted meat, pickled vegetables, and other foods can convert into nitrosamines in the human body under certain conditions, which are known carcinogenic substances.
Sodium nitrite is often added to sausages, salted meat, pickled vegetables, and other processed foods as a preservative and color fixative. However, sodium nitrite can convert into nitrosamines in the human body under certain conditions, such as acidic environments or high temperatures.
Nitrosamines are known carcinogenic substances, and long-term intake may increase the risk of cancer. Therefore, it is recommended to consume these processed foods in moderation and choose fresh, natural ingredients to reduce sodium nitrite intake in daily diets.
Knowledge Point 05: The “Five Tastes” of Food Refer to the Five Basic Tastes of Sour, Sweet, Bitter, Spicy, and Salty
The “five tastes” of food refer to the five basic tastes of sour, sweet, bitter, spicy, and salty, which collectively constitute people’s basic perception of food flavors.
The “five tastes” of food are important concepts in traditional Chinese medicine theory regarding food flavor classification. The five basic tastes of sour, sweet, bitter, spicy, and salty correspond to different food components and taste experiences.
Sour foods usually contain more acidic substances such as citric acid and acetic acid; sweet foods are rich in sugars; bitter foods may contain alkaloids, glycosides, and other components; spicy foods are mainly caused by capsaicin and other irritants; and salty foods mainly contain sodium chloride and other salts.
These five basic tastes intertwine and influence each other, collectively constituting people’s basic perception and preference for food flavors. In daily life, by reasonably combining foods with different tastes, one can enrich the taste experience on the dining table and satisfy people’s pursuit of delicious food.
