Quick Summary
Eating raw tuna from the grocery store does carry some risk of foodborne illness, but that risk is low if you follow basic food safety guidelines. The main things to consider are:
- Make sure the tuna looks fresh, with no discoloration or strong “fishy” odor
- Store tuna properly at 40°F or below and use within 1-2 days of purchasing
- Avoid tuna with high mercury levels if you are pregnant, nursing, or a child
- Handle tuna hygienically and avoid cross-contamination in the kitchen
- Sear or lightly cook the exterior of tuna steaks if concerned about parasites
- Pick a high-quality grocer that follows food safety protocols for fish
Following basic food prep guidelines greatly reduces any risk. Many people enjoy eating raw tuna from the grocery store with minimal problems. Those with a compromised immune system or pregnant women should take extra care or avoid raw tuna.
Potential Risks of Eating Raw Tuna
Eating any raw animal protein carries some degree of risk. Raw tuna is no exception. Here are the main risks to be aware of:
Parasites
Parasites like roundworms or tapeworms can sometimes be found in raw tuna. They are more common in wild tuna compared to farm-raised. Proper flash freezing to very low temperatures kills any parasites. But improper handling could allow parasites to infect the tuna at some point from catch to table. Thorough cooking kills parasites, but eating raw tuna means accepting a very small parasite risk.
Bacteria
Raw tuna can contain bacteria like Salmonella, Listeria, Staphylococcus, and others. Like other raw proteins, tuna requires diligent food safety practices during processing, transportation, storage, and preparation to prevent bacterial growth. Proper refrigeration and avoiding cross-contamination in the kitchen are key. Again, the risks are low but not zero.
Mercury and Other Pollutants
As tuna eat smaller fish, they can accumulate mercury and other pollutants from the ocean. The amount varies by species as well as the age and size of each fish. Large, long-lived predators like bluefin or bigeye tuna have higher mercury levels. Young skipjack has lower mercury. The FDA warns children, pregnant women, and nursing mothers to avoid high mercury fish, though modest amounts of low mercury tuna are considered safe. Follow advisories for your area.
Allergies
Those with fish allergies must avoid tuna entirely, cooked or raw. An allergy to one type of fish does not necessarily mean tuna allergy. But tuna allergy usually develops after eating tuna and can become more severe with repeated exposure. Tuna allergies most commonly develop in adults rather than children. Symptoms like skin reactions, gastrointestinal issues, and swollen airways can develop rapidly after exposure. Carry epinephrine if you have a known tuna allergy.
Grocery Store Handling
Most tuna arrives at grocery stores frozen solid at -30°F or below. This kills any parasites present. But improper thawing, storage, and handling at the store could allow bacterial growth. Make sure your grocer properly cares for tuna by keeping it well iced if thawed, monitoring temperatures in refrigerated cases, and avoiding cross-contamination when stocking display cases. Don’t purchase from markets with poor refrigeration or sanitation practices.
Choosing Fresh Tuna
Start with high-quality fresh tuna when shopping at the grocery store. Here’s what to look for:
Color
The flesh should have even coloration without dark spots or excessive bruising. All varieties of tuna have a pink to deep red hue when fresh. Discoloration, dulling, or browning of the flesh indicates the tuna is past its prime.
Smell
Give the tuna a smell test before purchase. Fresh tuna has a clean ocean “sea breeze” smell, not a strong fishy odor. Any ammonia-like scent means the tuna is starting to spoil.
Texture
Press the flesh gently with a finger. It should spring back and not leave much of an indentation. Fishy or mushy textured tuna is well on its way to spoilage.
Packaging
Whole tuna like steaks or loins should not be sitting in liquid. This speeds spoilage. The tuna should be sitting atop fresh ice, not drowned in melted ice water.
Cut Surfaces
Any cut surfaces of tuna steaks should look moist and shiny, not dried out. Discoloration around the edges indicates temperature abuse. Make sure your grocer is keeping tuna well iced and as close to 32°F as possible.
Shelf Life
Only purchase what you will use in the next day or two. Tuna steak or sashimi-grade tuna keeps 2-3 days maximum from the catch date if continuously held at proper refrigeration temperatures.
Labeling
Look for labeling indicating when the tuna was caught, processed, and “sell-by” or use-by dates. This helps you determine freshness and shelf life. Tuna more than 7-10 days old should be avoided for raw consumption.
How to Store Tuna Safely
Once purchased, proper storage prevents bacterial growth and rapid spoilage. Here are some storage tips:
Refrigerate Immediately
Get the tuna into the refrigerator within an hour of purchasing, ideally in an ice chest or cooler if you have a long trip home. Shoot for holding at 40°F or slightly below.
Use Ice
If the tuna came resting on ice at the store or market, continue icing it at home until ready to use. This maintains optimal temperature and moisture. Drain off melted water to avoid spoilage.
No Temperature Abuse
Avoid letting tuna sit out for extended periods during preparation or meal service. Bacteria multiply rapidly at room temperature. Refrigerate any leftovers immediately.
Air Tight Wrapping
Make sure tuna steaks or loins are well wrapped and sealed in freezer bags with the air pressed out. This prevents freezer burn which degrades quality.
Freeze for Long Term
Tuna intended for long term storage should be frozen at 0°F or below. Portion into meal-size pieces and avoid repeated freeze-thaw cycles.
Use Within 1-2 Days
For maximum food safety and quality, defrost frozen tuna overnight in the fridge and use within a day or two. Don’t refreeze thawed tuna.
Safe Tuna Handling at Home
Practice diligent kitchen hygiene when preparing raw tuna at home:
Clean Hands and Surfaces
Wash hands thoroughly before and after handling tuna. Sanitize counters, cutting boards, knives, and other surfaces both before and after contact with tuna.
Avoid Cross-Contamination
Use separate cutting boards and utensils for tuna versus other foods. Never let raw tuna or its juices contact other ingredients like produce or prepared foods.
Marinate Safely
If marinating tuna before use, make sure the marinade is well chilled in the refrigerator. Don’t save marinade after contact with raw tuna.
No Bare Hand Contact
Use gloves, tongs, chopsticks, or other utensils rather than bare hands to handle and serve raw tuna. This prevents transfer of bacteria and parasites.
Rinse Before Consuming
Give raw tuna a quick rinse under cold running water before serving as sushi, sashimi, poke, or tartare. This removes any surface bacteria present.
Serve Chilled
Arrange sashimi or tartare on chilled plates. Garnishes and sauces should also be well chilled. Keep tuna as close to 40°F as possible even during meal service.
Is Raw Tuna Safe When Pregnant or Immunocompromised?
Those with higher vulnerability to foodborne illness may wish to avoid raw tuna. This includes:
Pregnant Women
Pregnant women are advised to avoid high mercury fish like tuna. But regulated amounts of low mercury canned tuna are considered safe. Consuming raw tuna during pregnancy has a bit more risk so thorough cooking is recommended.
Nursing Mothers
Nursing mothers should also limit tuna intake due to mercury concerns. Avoid raw tuna when breastfeeding an infant if concerned about potential parasite exposure through breastmilk.
Young Children
Serve children well cooked tuna as opposed to raw. Developing bodies are more susceptible to both mercury and potential parasites.
Elderly
Those over age 65 may wish to avoid raw tuna. Immune function wanes later in life, increasing susceptibility to foodborne illness. Cooked tuna salads or casseroles are safer bets.
Immunocompromised
Anyone fighting cancer, living with HIV, or taking immune suppressing medications should only eat fully cooked tuna. Food safety vigilance is heightened for those with weakened immune systems.
Making Raw Tuna Safer
For those concerned about potential parasite presence, these steps make raw tuna somewhat safer:
Buy Sashimi-Grade
Seek out tuna labeled sashimi or sushi-grade when purchasing for raw consumption. These specialty products are most likely to have been blast frozen to control parasites.
Inspect Carefully
Examine tuna closely before use. Any odd textured spots may indicate parasite cysts though they are hard to detect by eye. Still, check for anything unusual.
Sear Exterior
Lightly sear tuna steaks briefly on each side using a very hot pan or blowtorch. This kills any parasites living on the exterior while leaving the interior raw.
Freeze Thoroughly
Home freeze tuna intended for tartare or carpaccio at -4°F for 7 days minimum to kill parasites. Thaw overnight in the refrigerator before use.
Acid Marinades
Marinating raw tuna briefly in an acidic mixture like citrus, vinegar, or wine may kill some potential pathogens on the surface.
Avoid At-Risk Species
Bigeye, bluefin, and yellowfin tuna have slightly higher parasite risks. Opt for skipjack, albacore, or tongol tuna varieties which tend to have less issues.
Enjoying Raw Tuna Safely
Here are some delicious ways to eat excellent quality raw tuna from the grocery store:
Sashimi
Thinly slice a sushi-grade tuna steak and arrange artistically on a platter. Serve with wasabi, pickled ginger, soy sauce, and chilled sushi rice.
Poke Bowl
Dice tuna into bite size pieces and toss with flavors like sesame oil, seaweed, avocado, onion, chiles, and ponzu sauce. Layer over sushi rice and mixed greens.
Tuna Tartare
Finely chop or mince tuna and mix with lemon, onion, capers, parsley, olive oil and seasonings. Shape into patties or serve spooned over crackers or crostini.
Tuna Carpaccio
Thinly slice or pound tuna loin into broad slices. Arrange over salad greens and drizzle with a vinaigrette and shaved parmesan cheese.
Seared Tuna Salad
Quickly sear fresh tuna steaks then slice over a bed of bitter greens, peppers, beans, new potatoes, and tomatoes. Whisk oil, vinegar, mustard, and herbs for a bold dressing.
Tuna Tartare
Finely chop extremely fresh tuna and shape into patties or balls. Serve over avocado slices with spicy mayo, fried wontons, or plantain chips for dipping.
Tuna Ceviche
Cube fresh tuna and “cook” by marinating in citrus juice, chili peppers, onion, cucumber, and cilantro. Allow to sit at least 2 hours for the citric acid to denature the proteins.
The Bottom Line
Excellent handling from catch to shopping cart is key to enjoying raw tuna from the grocery store. By selecting sushi-grade quality tuna, storing it properly, and preparing it with care, diners can enjoy the delicate texture and flavors of high-end tuna varieties at home. While a minimal level of risk exists when eating any raw animal protein, common sense food safety mitigates concerns for most non-vulnerable individuals. Expectant mothers, young children, the elderly, or immunocompromised individuals should avoid raw tuna. All others can eat raw tuna from reputable grocers with confidence by taking basic precautions.
