food that is stored uncovered can be a food safety hazard because

Food that is stored uncovered can be a food safety hazard because it allows bacteria and other contaminants to spread and multiply. Uncovered food in the fridge or other storage areas can lead to cross-contamination, where harmful bacteria from one food item can transfer to another, especially from raw to ready-to-eat foods. Additionally, uncovered food can allow allergens to transfer between foods, increasing the risk of allergic reactions. Bacteria can grow quickly when food is left exposed, especially if it enters the temperature danger zone (between 5 °C and 60 °C or 40°F and 140°F), which promotes the rapid multiplication of food poisoning bacteria. Properly covering food helps prevent contamination, maintain freshness, and reduce the risk of foodborne illness.