What Tuna Is Safe to Eat?

Tuna is a good source of protein, omega-3 fatty acids and other nutrients. Canned tuna is an ingredient in tuna salads and tuna sandwich filling recipes and fresh tuna is a top seller at sushi bars and other restaurants. Like most fish and shellfish, it contains trace amounts of mercury, which is safe for most people to eat in moderate amounts.

Fresh Tuna

• Purchase fresh tuna from a reputable fishmonger and make sure it is free of fishy odors and has firm, blemish-free flesh. Trim all the fat and skin from the tuna as that is where possible PCBs -- polychlorinated biphenyls -- are concentrated. Although PCBs were banned by the government in 1979, they still linger in the sediment and food in the fish environment. Defrost frozen tuna in the refrigerator to prevent bacterial growth.

Canned and Pouch Tuna

• The two most common types of canned and pouch tuna are chunk light and white albacore, available packed in water or oil. Store canned and pouch tuna at room temperature. Immediately discard tuna in containers that are bulging, rusted, dented or torn. Keep opened canned tuna or tuna salad in the refrigerator in a plastic or glass container. If stored properly, commercially packed tuna is safe to eat up to five years from date of purchase.

Consumption Guidelines

• The amount of tuna that is safe to consume is based on body weight and the type of tuna. White albacore tuna typically has higher levels of mercury than chunk light tuna. The recommendations are based on Food and Drug Administration test results and Environmental Protection Agency analysis of safe levels of mercury in tuna. The more you weigh, the more tuna you can safely consume. For example, a 20-lb. child can safely eat a 6 oz. serving of white albacore tuna every 10 weeks and the same amount of chunk light tuna every three weeks. By the time the child's weight is 60 lbs., consumption can be increased to every three weeks for white albacore and every seven days for chunk light tuna. An adult who weighs at least 150 lbs. can eat a 6 oz. serving of white albacore every nine days and chunk light every three days without exceeding recommended mercury consumption levels.

High Risk Groups

• Although the mercury levels in tuna are minuscule, it should be eaten more sparingly by pregnant women, nursing mothers, women who may become pregnant or small children. This precaution is based on studies that have linked nervous system disorders and development problems to mercury. Consult a doctor for guidance for safe tuna consumption if you or your family members fall into these categories.