No matter how perfect our preservation technology is, fruit will eventually spoil. So, can you still eat spoiled fruit?
Generally, the causes of spoiled fruit can be divided into three categories: mechanical damage from bumps and bruises, freezing injury from low temperatures, and moldy decay from microbial infection.
Among these three types of damage, mechanical damage is the most common. In this case, only the cells at the point of impact are broken, causing the cell contents to leak out. At the same time, due to cell damage, some colorless polyphenolic substances are converted into dark-colored substances, giving the wound a distinct appearance. Of course, this only causes an unpleasant sensory experience. As long as it is eaten shortly after the collision, this "spoiled fruit" will not affect our health. Whether this occurs largely depends on logistics and delivery. It is recommended to choose platforms with their own delivery services, so that even if a problem arises, you won't have to deal with the hassle of contacting the store after receiving the delivery.
Freezing injury often occurs in tropical fruits that are placed in the refrigerator. The most common example is the appearance of water-soaked spots on cucumbers stored in the fridge. This is because the low temperature affects the function of the cell membrane as a "city wall," ultimately leading to cell necrosis. If no bacteria come to take over the nutrients of these damaged cells, this type of spoiled fruit is relatively safe.
For spoiled fruit that has already become moldy, we must be cautious. This is because when we can see the mold with the naked eye, it means that a large amount of mold has already grown and multiplied inside the fruit. The most common mold on fruit is Penicillium expansum, and the patulin it produces can cause gastrointestinal disorders, edema, and other illnesses in the human body. Moreover, the process of patulin binding to human tissue cell membranes is irreversible, meaning they will linger on the cells. Even small amounts of patulin can cause long-term damage to cells.
It is particularly important to note that the patulin produced by mold can spread to other parts of the fruit. In a previous survey by the Chinese Academy of Preventive Medicine, it was found that the patulin content in the visually normal parts of a moldy apple was 10% to 50% of that in the moldy part. Therefore, cutting away the moldy part before eating is not necessarily safe. In this case, it is safer to throw the already moldy fruit in the trash.