Fungi, including molds and yeast, can flourish in any environment that provides moisture, nutrients, and air. Most molds grow in warm, humid conditions, but some strains also prosper under refrigeration.
Off-putting–and sometimes dangerous
Though molds may appear harmless, they can be dangerous when consumed by humans. Some molds produce fungal toxins, called mycotoxins. Mycotoxins can subsist in foods for long periods of time. They can also be resistant to heat. So cooking moldy foods may not make them safe.
Hardier than bacteria
Molds are often hardier than bacteria. They can tolerate higher levels of sugar and salt. That’s why one can find mold growth on jams, jellies, and syrups. Salted meats are also at risk. Bacon, ham, and salami are not immune to molds.
Mold growth may consume the acid in foods, changing its pH. As acidity decreases, and pH levels rise, the product becomes further susceptible to bacterial growth. That’s why a high-acidic food can become a low-acidic food, at risk for pathogenic (illness-causing) bacterial spoilage. Canned goods which show signs of mold should be discarded.