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How to Eat Fish Safely

posted Jun 24, 2016, 6:36 AM by   [ updated Jun 24, 2016, 6:38 AM ]
All month long, we've been reviewing the four key principles of food safety on this blog: clean, separate, cook, and chill. This week, we'll put what we've learned into practice by focusing on fish.

Back in February, we wrote about why fish is so good for your heart and your overall health. Despite knowing this, most of us don’t eat nearly enough fish. This may be due to concerns about storing and preparing fish safely or worries about possible contaminants like mercury. These are valid concerns, but most experts agree that the benefits far outweigh the risks when it comes to eating fish. Nevertheless, today we’re going to review what you need to know to feel confident about eating fish safely.

First, let’s talk about preventing foodborne illness. We’ll hit the key points in this post, but the FDA provides more comprehensive instructions for properly selecting, storing, preparing, and serving seafood here. When selecting fish at the seafood counter, use your senses of smell, sight, and touch to make sure it is fresh. Fresh fish should smell fresh—not fishy, sour, or ammonia-like. Whole fish should look firm, with shiny flesh, bright red gills, and clear eyes that bulge a little. Avoid fish with milky slime or discoloration, darkening, or drying round the edges. If you’re able to touch the fish, its flesh should spring back when pressed. For frozen fish, make sure the packaging is intact and avoid packages with frost or ice crystals, which may mean the fish has been stored for a long time or has thawed and refrozen.

As with any perishable food, get your fish into the fridge or freezer as soon as possible after purchasing it. If you’re planning to use fish within 2 days, you can store it in the fridge. Otherwise, it’s best to freeze it. When defrosting frozen fish, be sure to do it in the fridge or in cold water as we discussed last week.

When cooking fish, make sure it reaches an internal temperature of 145°F. Never eat fish if it has an ammonia smell after cooking. Finally, be sure to refrigerate any leftover fish within 2 hours.

With the popularity of sushi, you may be wondering if you have to cook fish. The FDA says it’s best to only eat seafood that has been thoroughly cooked. However, if you do choose to eat raw fish, previously frozen fish is your best bet. Freezing fish kills parasites, although it won’t kill other harmful microbes such as bacteria. Certain groups who are at a higher risk of foodborne illness should only eat seafood that has been cooked to an internal temperature of 145°F:
  • Pregnant women
  • Young children
  • Older adults
  • People with compromised immune systems
  • People with decreased stomach acidity 
What about your Sunday morning bagel and lox? For most people, refrigerated smoked seafood such as lox is safe to eat, but people at a higher risk of listeriosis, such as pregnant women, older adults, and people with weakened immune systems should not eat refrigerated smoked seafood because it can be contaminated with Listeria monocytogenes.

Lastly, if you catch your own fish, be sure you know how to safely clean, handle, preserve, and prepare it. This article provides some helpful tips.

In our post on the health benefits of fish, we talked about why the Dietary Guidelines for Americans (DGAs) recommend most people eat about 8 ounces per week of a variety of seafood. But some people are concerned about eating too much fish, particularly because fish can be contaminated with methylmercury, a neurotoxin that can be harmful to the brain and the rest of the nervous system if you get too much of it. For this reason, the DGAs recommend choosing seafood that is higher in EPA and DHA but lower in methylmercury to maximize health benefits and minimize risk. These include:
  • Salmon
  • Anchovies
  • Herring
  • Shad
  • Sardines
  • Pacific oysters
  • Trout
  • Atlantic and Pacific mackerel (not king mackerel, which is high in methyl mercury) 
It is especially important to choose seafood that is low in methyl mercury if you regularly eat more than the amount of seafood recommended in the Healthy U.S.-Style pattern (8 ounces for those on a 2,000 calorie diet).

These recommendations are for the general public, but what about pregnant women, breastfeeding moms, and young children? Although methylmercury poses a greater risk to these groups, the FDA and EPA encourage them to eat more fish, but to choose lower-mercury options because the nutritional value of fish is particularly important during growth and development, early infancy (for breastfed infants), and childhood. Pregnant women, women who may become pregnant, breastfeeding mothers, and children should eat 2-3 servings of fish per week. This means about 8-12 ounces for women. For kids, portion sizes should be based on their age, appetite, and calorie needs (see question 9 in the FDA/EPA's draft advice for more specifics).

In addition to choosing lower-mercury seafood, pregnant and breastfeeding women and children should avoid the four types of fish that are highest in mercury: tilefish from the Gulf of Mexico, shark, swordfish, and king mackerel. They should also limit white (albacore) tuna consumption. Adults can have up to 6 ounces per week, and children should have less (see question 12 for specifics). Last, when these groups eat fish caught from streams, rivers, and lakes, it’s important to pay attention to fish advisories on those waterbodies. If you can’t find any local fish advisories, the FDA and EPA recommend limiting consumption (see question 16 for specific amounts).

We hope this post will help clear up any confusion and will help you feel comfortable eating more fish safely. Your health will thank you!