Two Major Threats and Their Solutions

When it comes to the risks of eating raw meat, two primary concerns arise: bacteria and larger pathogens.

First, let's discuss bacteria. Various potentially harmful bacteria inhabit the digestive systems of animals, including pathogenic strains of E. coli and Salmonella. These bacteria are not present in the muscle tissue we consume; rather, they reside primarily in the lower digestive tract.

The preparation process is critical. Fish are gutted shortly after being caught, which helps keep the meat largely free of these bacteria. In contrast, during the slaughter of land animals, bacteria from their intestines can contaminate the meat, which is why store-bought chicken often carries a risk of salmonella.

The second concern involves larger pathogens, such as nematodes and flatworms, which can have complex life cycles. These parasites may burrow into the muscle of the fish, forming small cysts that can contain eggs or adult parasites, posing a health risk when consumed.

Fortunately, freezing is an effective method for eliminating these parasites. When you indulge in "fresh" sushi, you're most likely eating fish that has been frozen—this is beneficial. Unlike bacteria that enter a dormant state when frozen, these parasites cannot survive the cold, causing their cells to burst.

This freezing process is not optional; in the U.S., the FDA requires that all fish served to consumers, including sushi, must undergo freezing to eliminate any lurking parasites. The FDA outlines specific freezing guidelines, such as:

• Freezing at -4°F (-20°C) for 7 days.
• Freezing at -31°F (-35°C) until solid and storing at that temperature for 15 hours.
• Freezing at -31°F (-35°C) until solid and then storing at -4°F (-20°C) for 24 hours.

Often, this freezing occurs on fishing vessels, where fish are flash-frozen at -40°F. When you enjoy "fresh" sushi, it likely originated as frozen fish, which is a good thing for both taste and safety.

Nonetheless, the FDA's guidelines are not always enforced strictly. This can lead to confusion among restaurants, suppliers, and distributors about who is responsible for freezing the fish. Some areas, like New York City, have enacted laws requiring proof of freezing before serving fish, much to the surprise of uninformed sushi lovers who do not realize this process is already in place.

Blind taste tests have shown that frozen fish can taste just as good, if not better, than fresh fish. Flash freezing locks in flavor, ensuring your sushi tastes delightful and is safe to eat.

But why can we enjoy raw fish while avoiding raw hamburger or chicken?

The primary reason relates to microbial safety: cleaning raw fish makes it easier to eliminate bacteria from the intestines that could contaminate the meat. However, this doesn't mean sushi is entirely free of risk; salmonella outbreaks have been linked to sushi consumption.

The second reason concerns parasites; the "fresh" sushi you eat has likely undergone flash freezing, effectively killing larger parasites. All sushi should be subject to this freezing process, which has no adverse effect on taste.

One final note: what about dishes like beef tartare or rare steak? Interestingly, while salmonella can infiltrate chicken meat, E. coli on beef typically remains on the surface. This allows for the consumption of rare beef with just a sear on the outside, while chicken must be thoroughly cooked to ensure safety.