Mold on food does not always mean the same thing. With hard cheeses such as cheddar, Parmesan and Swiss, mold generally cannot penetrate deeply because of the product’s low moisture content. Food-safety guidance says at least one inch, or about 2.5 centimeters, should be cut away around and below the moldy area without allowing the knife to touch the mold. Soft cheeses such as ricotta, cream cheese and cottage cheese should instead be discarded completely because microscopic mold filaments can spread well beyond the visible patch. A similar caution applies to soft fruits and other high-moisture foods.
Meat presents a different risk because bacteria are the main concern. An unpleasant odor, sticky or slimy surface or other obvious signs of spoilage are reasons to throw meat away. More importantly, dangerous bacteria such as Salmonella, Campylobacter and certain strains of E. coli may be present even when meat looks and smells normal. Smell and color therefore cannot reliably establish whether meat is safe. Proper refrigeration, storage times and cooking to a safe internal temperature remain essential.
Mold on nuts and grains can also pose a danger because some fungi produce harmful mycotoxins. The practical rule is that certain firm foods may sometimes be salvaged by removing a sufficiently large affected area, while moldy soft and high-moisture foods should generally be discarded. Meat showing signs of spoilage should not be eaten, and when there is genuine doubt about a food’s safety, throwing it away is the safer choice.
