Like most foods, fruits can go bad and become harmful to your health. A peach rotten on the inside, for example, won't have the same flavor and nutritional value as fresh fruit. Plus, it may contain mold and dangerous bacteria that can lead to foodborne illnesses.
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Spoiled fruits can be contaminated with bacteria, molds and other pathogens that are not visible to the naked eye. Watch out for any foul odors, moldy or mushy spots and signs of discoloration.
Why Do Fruits Go Bad?
About 20 percent of all fruits and vegetables harvested each year end up in the trash due to microbial spoilage, according to an April 2016 review published in Food Microbiology: Principles into Practice. Some are contaminated with bacteria or mold, while others go bad because of high temperatures, oxidation or increased humidity. Spoilage microorganisms can affect fresh produce anytime during harvesting, handling, distribution or storage.
Sometimes, the culprit is ethylene gas, a plant hormone that accelerates fruit ripening. As fruits reach maturity, their color, texture, flavor and nutritional content will change.
Polyphenol oxidase (PPO), a naturally occurring enzyme in plants and animals, plays a role, too. This compound is responsible for oxidative browning, points out a research paper featured in Current Science Perspectives in April 2016. Apples, for instance, are particularly sensitive to PPO, which explains why they turn brown within hours.
Most fruits produce ethylene gas. Apricots, guavas, bananas, avocados, plums, prunes, papayas and mangoes are just a few to mention. For this reason, they should not be stored next to ethylene-sensitive vegetables and legumes like cabbage, cauliflower, eggplant, leeks, mushrooms or watercress.
Bad cherries and other fruits that have changed their color and texture may also harbor mold, especially when stored in warm and humid conditions. However, some molds can grow on refrigerated foods too, warns the USDA Food Safety and Inspection Service. Soft fruits, such as peaches and bananas, can be contaminated below the surface and should be discarded immediately.
Signs of Fruit Spoilage
As you see, foods can deteriorate quickly because of natural biochemical changes or bacteria growth. These processes affect their taste, odor, texture and appearance, notes the Institute of Food Technologists. Fruits are particularly vulnerable to Bacillus, Clostridium, Erwinia carotovora and other bacteria species. They may also be contaminated with molds, such as Aspergillus and Penicillium.
Spoiled fruits, such as bad cherries or rotten apples, typically have a slimy texture and unpleasant odors. You may also notice changes in their color. Cherries, for example, can go from bright red to brown. Mold is often visible on their skin.
The bacteria responsible for fruit spoilage don't cause food poisoning, state the experts at Michigan State University Extension. However, this doesn't mean that spoiled fruits are safe or edible. In addition to spoilage bacteria, they might be contaminated with viruses, molds, fungi and other microorganisms. As it turns out, there are about 200 foodborne pathogens, but you cannot taste, smell or see them.
Michigan State University Extension advises against eating any foods that smell or taste bad. Also, watch out for any changes in their texture. If the fruits in your fridge are mushy or slimy, it's safer to discard them.
Is an Overripe Peach Safe?
Sometimes, it can be difficult to tell whether a peach, banana or other fruit is overripe or spoiled. Generally, an overripe peach should not have any soft spots or signs of mold. If it's rotten or spoiled, it will most likely become slimy. Its smell and taste may change, too.
As mentioned earlier, peaches are soft fruits with high moisture content. They're about 88.8 percent water and provide 60 calories per serving (1 cup or 5.4 ounces). Due to their high water content, they can be contaminated with mold below the surface and may lead to foodborne illnesses. Firm fruits, on the other hand, are more resistant to mold — if you notice small mold spots, you can simply cut off the damaged area.
If you have a bruised peach, you may still eat it safely. The Greater Chicago Food Depository recommends cutting away the bruised area before consumption. The same goes for bruised nectarines, pears, plums and other soft fruits. Bruising isn't always a sign of spoilage.
However, a bruised fruit that is discolored or squishy may not be edible. If it has a strange smell or wrinkled skin, consider throwing it away.
- Food Microbiology: Principles Into Practice: "Spoilage of Vegetables and Fruits"
- Journal of Experimental Botany: "Banana Ethylene Response Factors Are Involved in Fruit Ripening Through Their Interactions With Ethylene Biosynthesis Genes"
- Current Science Perspectives: "Extraction of Polyphenol Oxidase From Green and Red Apple Fruits and the Effect of pH Variation on the Activity of the Enzyme"
- Produce for Better Health Foundation: "About the Buzz: Certain Fruits and Vegetables Should Not Be Stored Together?"
- USDA Food Safety and Inspection Service: "Molds on Food: Are They Dangerous?"
- Institute of Food Technologists: "The Ick Factor: Microbial Spoilage"
- Michigan State University Extension: "Food Spoilage and Food Pathogens, What’s the Difference?"
- USDA FoodData Central: "Raw Peaches"
- Greater Chicago Food Depository: "Salvageable Fruit and Vegetable Guidelines"