Raw Seafood: Is it Safe for Consumption?

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In the last 30 years, the love and popularity of sushi has exploded beyond measure. It has now become a multi-billion dollar industry with thousands of restaurants around the country. Sushi rolls can also be purchased at many grocery stores. Without a doubt, Americans are consuming more raw seafood than ever before.

The soft, raw texture is enticing and even addictive for some people. With sushi, it seems like either you love it or hate it, no in-between. But is raw seafood safe?  Are there any studies that show legitimate concerns with regular consumption?

A Rise in Parasites in Raw Seafood

This may be the last thing sushi lovers want to hear, but the number of parasites in fish has increased in the last 50 years. A study that was done by the University of Washington found something pretty alarming. It sought out to test the levels of one single nematode parasite known as Anisakiasis, or herring worm. One study found a 283-fold increase in this transmission to humans since the 1970’s!

These parasites attach to the intestinal wall and can cause serious infections. While initial symptoms may not always be noticed, these parasites can cause inflammation and  insidious damage. As science discovers the incredible importance of gut health, keeping it free of toxicity becomes increasingly important.


Vibriosis is a dangerous infection that can occur from eating raw or undercooked seafood. Vibrio occurs mostly from oysters, but can be found within mussels, clams, scallops, and other seafood. Toxic waters along with poor handling practices are two of the main causes of vibrio infections. The symptoms of this infection may be very severe.

Most people will recover after 5-7 days, but people with weakened livers and immune systems may need hospitalizing if sepsis occurs. In addition, people that take antacids may also be more prone to vibriosis when eating raw seafood. To destroy vibrio, make sure to cook seafood to an internal temperature of 145 F for 20 seconds.

Listeria in Raw Seafood

Listeria bacteria is somewhat common and may be found in raw sprouts, vegetables, and dairy if kept in poor conditions. The biggest concern with listeria infections is for people with compromised immune systems and pregnant women. Consequently, the infection may be passed to a newborn through the placenta. A listeria infection can burrow into the nervous system, where it can lead to meningoencephalitis.

Bacillus cereus

Bacillus cereus isn’t as severe in the potential health consequences, but it does pose some risk. This bacteria is mostly present in the rice of sushi rolls. It is an anaerobic bacteria that can produce toxins when left at room temperature for too long. Rice used for sushi should be bathed in a vinegar solution to lower the PH to a level that kills these microbes. Heat doesn’t do a very good job killing bacillus cereus, it requires an acidifying substance.

Clostridium difficile

Like Listeria, clostridium difficile is found in many items other than seafood. However, it’s still a legitimate concern when eating raw seafood. One study found that almost 5% of fish and seafood at a Canadian grocery stores tested positive for clostridium. This isn’t the only study that has shown shockingly high levels of contamination in food.

C. diff bacteria is sometimes a problem for those following a round of antibiotics. It can grow out of control and cause months or years of health problems if not contained. Such can be the same when eating contaminated sushi, not ever knowing how the problem began. Raw seafood served in  restaurants should be fresh, but many buy from local stores not knowing the level of contamination.

Another overlooked problem with consuming raw seafood isn’t about the raw fish, but who’s making it. Sushi is usually prepared with a lot of cupping and shaping with hands that may or may not be sanitized. Studies have shown that sometimes the illness occurs just from the amount of food handling needed to make sushi. Many sushi chefs don’t like wearing gloves and may not sanitize properly. If you truly enjoy sushi and aren’t willing to give it up, it’s important to have an arsenal of natural anti-microbial compounds.

Medicine like raw propolis, olive leaf, thyme, strong probiotics, oregano, nano-silver, cranberry, and other extracts may offer some protection against the proliferation of harmful bacteria. These may not offer 100% protection, but being aware of the risks of raw seafood can help prevent serious illness that many have experienced.