Infants and young children are particularly vulnerable to food poisoning because their immune systems aren't fully developed and their lower body weight means they can get sick from a smaller amount of bacteria. Most types of food contamination can't be detected by sight, smell, or taste. So while food left unrefrigerated may seem OK, it may not be safe to eat. To protect your child from contracting a food-borne illness, keep these special precautions in mind in addition to standard food-safety advice. For more information on food poisoning, see "When Bad Food Happens."

• If your baby doesn't finish his or her bottle, discard the contents instead of refrigerating them for later. Bacteria from an infant's mouth can remain in the bottle and multiply, even after the bottle is reheated. Likewise, don't feed your infant baby food and refrigerate the remainder, since bacteria from the spoon may have contaminated it.
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• If milk, formula, or baby food is left unrefrigerated for more than two hours, throw it out. "That half-eaten jar of baby food that has been sitting in your hot car is more of a bacterial incubator than lunch," says Alfred Sacchetti, M.D., of the American College of Emergency Physicians.
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• Follow the "use-by" dates on formula cans. It's the manufacturer's way of warning you that the chemical composition may not be the same after a certain time period, Sacchetti says.
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• Don't give infants or young children unpasteurized milk, food that contains unpasteurized milk, or unpasteurized juices, since they may contain harmful bacteria. In September 2006 California health officials recalled unpasteurized milk and milk products from the Fresno company Organic Pastures after four children were sickened with E. coli bacteria.
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• Don't feed honey to a baby under 12 months old. It harbors bacterial spores that can cause botulism, a rare but potentially fatal disease. Many bacterial spores are typically harmless to adults and older children but can have a deadly effect on a baby.