New Rules for the Safe Use of Seasonal Seafood
An old rule of thumb warns that shellfish should be avoided during the non-P months – May, June, July, and August – just around the time of year when many of us head to the shore and want to sample the seafood.
Do you really need to skip shellfish all summer? Is the old adage about giving up sushi on Mondays true? We decided to take a look at some of the old and new guidelines for eating seafood to see what’s outdated, what new regulations are in effect, and how to fill up on water activities without risking food poisoning (or worse.)
Seasonal Recommendations
According to Keith Brogan of the National Oceanic and Atmospheric Administration’s Department of Fisheries, the old “R months” rule came from several places. First, oysters spawn in the summer, and during this process their glycogen (the accumulated starch that gives the sweet taste) turns into gametes, altering flavor and texture so that they are, as Brogan put it, “not very good.” Second, says Brogan, “On those days when there was no refrigeration, you didn’t want to eat an oyster that sat in the blazing sun all day.”
These days, says Brogan, “There really are no months without an R, because now we have a chill!” And the new rules also mean that the R rule can be safely canceled. Some states have oyster curfews so that growers have to harvest their oysters before noon or mid-morning, depending on the month, “so the shellfish don’t stay outside in the midday heat,” she says. So while oysters may not taste the best during the hot summer months, they shouldn’t make you nauseous (and the same goes for other shellfish).
Another possible source of the R-month rule is that harmful algal blooms are more common in warmer months, according to the EPA , which also warns that climate change is making this bloom more common year-round. Certain types of phytoplankton produce toxins, which in turn can enter the food chain when shellfish or other sea creatures consume the phytoplankton, leading to foodborne illness. They can have serious consequences, ranging from indigestion to numbness, tingling, and even mild memory impairment, says Dr. Lynn Grattan of the University of Maryland School of Medicine, who studies the effects of marine toxins on coastal communities.
It’s a good reason to be careful when eating shellfish, but it doesn’t necessarily mean avoiding shellfish in the summer months, says Grattan. “While there are some regional patterns of harmful algal blooms, in the United States, some fish or shellfish species can retain the toxin for extended periods of time. Thus, the bloom may end, but fish or shellfish may still be toxic. “
Fish and shellfish from the United States are the best choice, according to Grattan. “The US has strict fisheries, collection and distribution regulations that are closely and competently monitored,” including monitoring harmful algal blooms. Grattan advises consumers to monitor and comply with any warnings or closures from government health or fisheries and wildlife departments, and pay close attention to any recommendations offered on the restaurant’s menu. Harmful algal blooms have been reported in all coastal states as well as in the Great Lakes. Many states issue local warnings, and NOAA maintains an early warning website for harmful algae blooms nationwide, where you can also subscribe to bloom updates for specific waters. These warning systems are imperfect, and Grattan notes that “seafood consumption is the leading cause of foodborne illness with known etiology.” But you can reduce your risk by eating local seafood and being aware of all the warnings, no matter the time of year.
Weekly rules
In his 2000 memoir Kitchen Confidential, Anthony Bourdain said he never orders fish on Mondays. He wrote that fish markets in New York were closed on weekends and restaurants did not receive fresh fish on Sundays, so the fish probably stood there for a couple of days on Monday. This rule has definitely become popular, with many online forums discussing whether sushi and other seafood is banned in restaurants on Sundays, Mondays, or both.
But last year Bourdain himself declared the rule obsolete because the demand for and knowledge of seafood is much higher than even 15 years ago, and restaurants have adjusted their schedules and supplies accordingly. “It was a different world. We now know what good fish should look and smell like, ”he told Business Insider in 2016,“ and the market needs to react to that. ” So as long as this is a reputable restaurant, any day of the week is fair game.
Remembering that Mercury
Regardless of what time of year or day of the week you eat seafood, one rule remains true: do not overdo it, or you risk mercury poisoning. The heavy metal accumulates most in large predatory fish such as swordfish, tuna, and sharks, but other species, such as blue gills and striped bass, can contain enough mercury to cause problems in people who regularly eat fish. Pregnant or lactating women should avoid these animal species entirely ( complete FDA guidance can be found here ). Dr. Michael Hochfeld, MD, who specializes in mercury poisoning, says some people who eat fish several times a week show signs of mercury poisoning. “In our clinic, the theme is constantly encountered:” For health reasons, I ate a can of tuna every day for many years. “
Hochfeld strongly believes that fish is part of a healthy diet, up to once or twice a week. He advises people who eat fish more often to pay close attention to mercury levels in fish and try to eat fish that are very low in mercury and stick to 3-4 ounces per meal. Smaller species such as anchovies, sardines, and scallops are especially poor in mercury; catfish, salmon, and tilapia are also safe bets. There are many tutorials for more information, including this one from NRDC .