FAMILY MEDICINE® COLUMN

By John C. Wolf, D.O.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

GROCERY TABLOIDS BIG ON CREATIVE WRITING, SHORT ON MEDICAL FACT

Question: Our local grocery store sells prepared salads in bags. Some of them add sodium benzoate and potassium sorbate, supposedly to preserve freshness. A newspaper sold at the cash register said these chemicals should not be eaten by humans because they are poisonous even in tiny portions. Is it safe to eat these salads or not?

Answer: There are a large number of “natural foods” advocates in my community that I’m sure would say the checkout counter tabloid is telling the truth. Despite the health food advocates’ concerns and testimonials to the contrary, you can consider any commercially prepared food to be safe -- assuming you follow customary storage and cooking temperature precautions.

I don’t want to start out on the wrong foot and alienate my “organic gardening” friends, however. I shop at my local farmer’s market and buy their produce not because it is free from approved preservatives, but instead, because it is picked fresh at each product’s peak of ripeness. Because of this, it just tastes better than the grocery store varieties that have been shipped across the country.

Now to the preservative issue. Without preservatives there would be substantially more food lost to spoilage. That means you and I would pay more for our dinner and also have a more limited seasonal choice of menu offerings. I’m sure you are thinking about fruits and vegetables, but even that box of cereal on your shelf wouldn’t stay fresh very long without preservatives.

The U.S. Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition tests and approves food additives and preservatives. The approved list currently has more than 2000 individual items it. Interestingly, the list does not include one old standby that can be used as both a flavor-enhancer and a preservative -- sodium chloride (Na-Cl), otherwise known as table salt. The chemicals you specifically mentioned, sodium benzoate and potassium sorbate, are on the approved list.
Sodium benzoate is a naturally occurring polyunsaturated fat that inhibits the growth of bacteria, yeast and fungi. It has been used in foods for more than 80 years. The FDA limits the concentration of this chemical in prepared foods to 0.1 percent by weight even though it can occur in somewhat higher concentrations in even organically grown cranberries and prunes. In other words, it is common and safe.

Sodium benzoate doesn’t work very well unless the food being treated is kept somewhat acidic. To accomplish this it is often necessary to add another preservative. Vitamin C, also known as ascorbic acid, would work but it doesn’t last very long with exposure to air and sunlight. Potassium sorbate, which is the potassium salt of sorbic acid, is a good choice for acidifying many foods. It is a polyunsaturated fat that has been safely used to inhibit the growth of mold for more that 150 years. The body readily metabolizes it into energy, water and carbon dioxide.

The availability of food is a serious health concern, but fortunately, it is only a concern for a small percentage of the U.S. population. A far greater risk is bacterial contamination of food. That is why milk is pasteurized, meat is refrigerated, and many other foods contain preservatives. You can view the FDA approved list of preservatives at http://vm.cfsan.fda.gov/~dms/eafus.html.

I don’t know about you, but I’m always a bit disappointed when my grocery store checkout line moves quickly. When it does, I don’t get to read those tabloids. Their lack of accuracy and abundant sensationalism is what heightens their entertainment value.

"Family Medicine" is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701. Past columns are available online at http://www.FamilyMedicineNews.org.