Contamination of Oysters, Fish, and Spices

Climate change may be sickening our oysters.  Industrial pollution in Asia may be contaminating our seafood.  The pepper shaker on your table may be harboring salmonella.  What follows supplies the details and suggests how you should respond.

Bacteria in oysters:

 What's happening to oysters is not just a pity for oyster lovers.  It's also more evidence that global warming is upon us, and that's not good.  Proverbial wisdom has told us to eat raw shellfish only in months that have an R in the name, in other words, colder months.  Why? Bacteria in the vibriosis family have, until this past summer, been linked mainly to oysters raised in the warm salt water of the Gulf of Mexico.  However, says the Huffington Post, pubic health officials in Connecticut, Massachusetts, and Washington state recently reported that "about twice as many people this year have contracted the food-borne illness vibriosis after eating raw oysters and clams as do in a typical summer."  As of mid-August, the number reached 113. 

The news is even worse than that figure suggests because many cases of gastric distress are not reported. There are many different types of bacteria in the vibrio group including one that causes cholera.  Vibrio parahemolyticus causes severe diarrhea.  So does Vibrio vulnificus, but, especially in people with an underlying disease, it can  also lead to septicemia (blood poisoning), a life-threatening infection.

In response to this outbreak, some commercial oyster beds have been shut down in Connecticut, Massachusetts, Virginia, New York, and New Jersey.  The states of Connecticut and Washington also announced recalls for potentially contaminated oysters. 

To clarify the connection to global warming: The disease that once was linked to warmer, more southern waters is now turning up in significant numbers in the colder waters of the Northeast and Northwest.  According to the Huffington Post, "This recent news may be a sign that climate change is pushing the disease northward, as scientists have long believed it could." 

Recommendation for consumers:

• ŸIf you must eat oysters even in the summer, cook them first.   This is especially good advice if you have a weakened immune system.

Mercury in fish:

A joint study conducted by the University of Michigan and the University of Hawaii revealed an increase in mercury levels in fish caught near Hawaii.  The source?  Air pollution from power plants in China and India.

What?!  Air pollution contaminating fish?  How does this happen? Here's the explanation from Food Safety Tech: "Mercury produced by the coal-burning power plants in these northern Pacific countries travels thousands of miles through the air before rainfall deposits it on the ocean floor near Hawaii.  From there, it's passed on to humans who consume contaminated Pacific Ocean fish, such as tuna and swordfish."

Why is there more mercury in these two types of fish than in others?  Food Safety Tech explains that predatory fish feed at greater ocean depths, where most of the methylmercury is produced. Fish that feed near the surface of the water--for example, mahi-mahi and yellowfin tuna--have less mercury toxicity. 

Why is mercury so bad for you?  The amount of mercury found in the tissues of these fish can damage a person's heart, central nervous system, and immune system.  

Recommendations for consumers:

• ŸMercury levels are not listed on packages of seafood.  Therefore, the Environmental Protection Agency (EPA) recommends limiting consumption of types of fish known to have higher levels of mercury, especially swordfish and opah.
• Mercury is especially harmful to fetuses and young children. Pregnant women are commonly warned to limit the amount of fish they eat.

Recommendations for science and industry:

• ŸThere is a need for international controls of mercury in Asian power plants.
• We need to find ways to degrade mercury so that it no longer creates toxic seafood.

Salmonella in spices:

The New York Times recently reported this statistic from the FDA:  in a recent study of 20,000 imported food shipments, 7% of spice lots were found to be contaminated with salmonella.  That was double the average amount of contamination found in all other imported foods.  About 15% of basil and oregano shipments were tainted, and high levels of contamination were also detected in sesame seeds, curry powder, and cumin. For pepper, the contamination level was 4%. 

Salmonella is one of the most common causes of food-borne illness, sickening about 1.2 million U.S. residents each year, causing diarrhea, fever and cramps.  Salmonella infection can be serious and even cause death if it spreads to the bloodstream and affects the function of vital organs.  Infants, the elderly, and those with weakened immune systems are most likely to develop significant complications from this pathogen.

The highest numbers of contaminated spices come into the U.S. from Mexico and India. A recent FDA study found contamination in 14% of Mexican samples and 9% of samples from India (which sends the U.S. about quadruple the number of spices that Mexico does).  The FDA considers this problem a significant matter that needs to be addressed promptly.  According to the New York Times, "Indian government officials are quietly pushing some of the most far-reaching changes ever in the way farmers here [in India] pick, dry, and thresh their rich bounty."

According to NPR, almost all spices used in the U.S. are imported.  After they're harvested from plants, they're commonly laid on the ground to dry, where it's easy for birds and other animals to gain access to them.  Salmonella comes from this contact with animals. Salmonella can be killed by irradiation, heat (pasteurization), and treatment with ethylene oxide gas.  But there's no requirement that treated spices be labeled as such, so consumers usually don't have this information.  Moreover, says NPR, "some of the treated spice samples that the FDA tested still had traces of salmonella."  It doesn't take much salmonella to make a person sick. 

The FDA does not allow into the country any imported foods that it finds have even a small amount of salmonella. However, says the New York Times, the FDA visually inspects less than 1% of all imported foods and does lab tests on only a small fraction. 

Recommendations:

• ŸGet the pepper shaker off the table. Bacteria (including salmonella) are killed by cooking (to 160°F), so the best advice is to add all spices (including pepper) to your food during the cooking process rather than at the table.  That's what most Asian cooks do. 
• ŸThe FDA will be making public more information on the agency's spice analysis later this fall.  Watch for that news.  It could change your buying and cooking habits.

Source(s):

huffingtonpost.com "Vibrio Risk Prompts Oyster Recalls, Bed Closures Far North of the Gulf of Mexico"

http://www.huffingtonpost.com/2013/09/03/vibrio-oysters_n_3861502.html

thefreedictionary.com "Vibriosis"

http://medical-dictionary.thefreedictionary.com/Vibriosis

foodsafetytech.com "Asia Contaminating Fish Population, Says New Study"

http://www.foodsafetytech.com/FoodSafetyTech/News/Asia-Contaminating-Fish-Population-Says-New-Study--1554.aspx

nytimes.com "Salmonella in Spices Prompts Changes in Farming"

http://www.nytimes.com/2013/08/28/world/asia/farmers-change-over-spices-link-to-food-ills.html?pagewanted=all&_r=0

npr.org "Your Kitchen Spices Can Often Harbor Salmonella"

http://www.npr.org/blogs/thesalt/2013/08/28/216550862/your-kitchen-spices-can-often-harbor-salmonella