When there are few competitive microorganisms in the gut, pathogenic bacteria such as Salmonella, Shigella, E. coli, etc., if they survive the stomach, can easily multiply. The body's third defense is the immune system. Pregnant women, elderly people, very young children, and other individuals with compromised immune systems must choose food carefully to avoid being made ill by low levels of pathogens that penetrate into the blood and can infect the body. In addition, there are auto-immune diseases such as AIDS that make one more susceptible to illness. The longer raw, high-moisture foods are on display, the greater the amount of deterioration and spoilage.
Most microorganisms grow best at high levels of moisture.
Spoiled food does not necessarily mean hazardous food. It is merely unattractive and undesirable. The American consumer who smells and tastes the food determines whether or not a food item is spoiled. Appearance and smell are indicators of freshness. Some foods are produced using spoilage organisms.