Wednesday, May 20, 2015

In America, is our food, in fact, too clean?


Q: Is it true that we may be washing too many germs off the food we eat?

A: With the recent recalls of millions of gallons of ice cream as well as several tons of hummus, pine nuts, frozen vegetables and various meat products, you might think the U.S. food supply is an unholy mess.

It’s not. It’s arguably the safest in the world.

Yet despite continually improving quality controls, the number of cases of foodborne illness has remained stubbornly high since the 1990s. Some experts wonder if we’ve reached a point of diminishing returns in food safety — whether our food could perhaps be too clean.

Industrial food sanitation practices — along with home cooks’ antibacterial veggie washes, chlorine bleach kitchen cleaners and sterilization cycle dishwashers — kill off so-called good bacteria naturally found in foods that bolster our health.

Moreover, eliminating bad or pathogenic bacteria means we may not be exposed to the small doses that could inoculate us against intestinal crises.

“No one is saying you need to eat a peck of dirt before you die to be healthy,” said Jeffrey T. LeJeune, head of the food animal research program at Ohio State University. “But there is a line somewhere when it comes to cleanliness. We just don’t know where it is.”

The theory that there might be such a thing as “too clean” food stems from the hygiene hypothesis, which holds that our modern germaphobic ways may be making us sick by harming our microbiome, which comprises all the microscopic beasties — bacteria, viruses, fungi, mites, etc. — that live in and on our bodies.

Research so far has focused primarily on cesarean births and not breast-feeding, which may inhibit formation of a robust microbiome, and antibacterial soaps and antibiotics, which diminish the established microbiome.

A result is an immune system that essentially gets bored — spoiling for a fight and apt to react to harmless substances and even attack the body’s own tissues. This could explain the increase of allergies and autoimmune disorders such as asthma, rheumatoid arthritis and inflammatory bowel syndrome.

All of this is hard to prove.

“We have these tantalizing bits of evidence that to my mind provide pretty good support for the hygiene hypothesis, in terms of food-borne illness,” said Guy Loneragan, an epidemiologist at Texas Tech.

It is worth noting that serious foodborne diseases — ones that make it into the news, like listeria, salmonella, E. coli, cryptosporidium and campylobacter — are mainly diseases of immuno-compromised populations. That’s getting to be a significant number of people, thanks to our aging population.

“It’s a cruel reality that anyone 55 and older is potentially immuno-compromised,” said Haley Oliver, assistant professor of food science at Purdue University. Also included are young children, pregnant women, people with HIV, cancer patients, organ recipients and anyone who takes a lot of antibiotics.

The three people who died after eating listeria-laced Blue Bell ice cream ate it while inpatients at a hospital in Wichita, Kansas. Local health officials said listeriosis may have contributed to but did not cause these people’s deaths. Seven more people were sickened nationwide.

That leaves millions who, experts said, ate the remaining five years’ worth of ice cream included in the recall and didn’t have so much as a stomach cramp. Research shows listeria is commonly found in dirt and in households.

“When disease happens, you have to have a perfect storm of enough of the pathogen present in the food, the person ate enough of that food and that person was immuno-compromised,” Oliver said. “But because of the hygiene hypothesis, we may be becoming a more naive or vulnerable population.”

– Kate Murphy, The New York Times