Oxidation is a concern with open food. While modern cans are made from steel or aluminum, acidic foods often require a polymer lining inside the can. If this lining is damaged, the acid can corrode the metal, leading to oxidation. While the oxidized metal itself isn’t known to be toxic, it can impart a significantly unpleasant taste to the food.
Contamination is a major risk with open food. Airborne water droplets carrying harmful microbes, such as Listeria, can settle into the food. Listeria can thrive even in refrigerated environments. Cross-contamination can also occur, for instance, if raw meat juices drip onto other foods. Keeping raw meats on the bottom shelf of the refrigerator can help mitigate this risk, but it doesn’t eliminate it entirely. While contamination through this route is relatively uncommon, the potential consequences make it a significant concern.
Food can also absorb undesirable flavors and odors from the surrounding environment. Volatile compounds, responsible for food flavors, can easily escape into the air. Refrigerators and freezers can harbor mold and mildew, which produce volatile compounds contributing to a musty smell. Foods with high moisture or fat content are particularly susceptible to absorbing these unwanted flavors. For example, an ice cube placed in a beverage can sometimes impart a strange taste due to the absorption of volatile compounds from the surrounding air and ice.
