Safe Shellfish Year-Round Oysters are wholesome and nutritious. They are a low-calorie, low-cholesterol source of protein. Oysters are also an exceptional source of zinc, a mineral associated with strengthening the immune system and a prime source of omega-3, a fatty-acid linked to lowering the risk of heart attack, breast cancer, prostate cancer, and stroke. Folklore says that shellfish are safe to eat only in months with the letter “R,” which excludes the warmer months of May through August. But this caution is outdated, says Paul DiStefano of the U.S. Food and Drug Administration. It came about, “when we didn’t have the refrigeration controls that we have today—controls that are monitored by state and federal officials as part of the cooperative program.” “If the cooperative program is followed, FDA recognizes raw shellfish to be safe year-round for healthy individuals to eat,” says FDA's DiStefano. But people who have weakened immune systems from diseases such as AIDS, cancer, diabetes, and liver and kidney disease should avoid raw protein foods in general, including raw shellfish, he says. “But all individuals can enjoy shellfish that is cooked.” DiStefano recommends buying shellfish from a reputable dealer, and looking for the tag that identifies where and when the molluscan shellfish were harvested and processed. By law, retail markets and restaurants are required to keep these tags for 90 days after the shellfish are sold to ensure that if there is an illness, the shellfish implicated can be traced back to the supplier and the harvesting waters. “There’s nothing wrong with asking to see the tag,” says DiStefano. “And if the seller can’t produce it, walk away.”