FAMILY MEDICINE® COLUMN

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

HAVE A MEMORABLE, NOT REGRETTABLE, 4th OF JULY PICNIC!

Question: In the summer we picnic a lot -- including a large family gathering on the 4th of July. Last year on the 4th about half of us got sick from food poisoning. We blamed the mayonnaise in the potato salad, so we took it off the picnic menu. Do you have any additional suggestions for making our picnics less memorable -- but more enjoyable -- this year?

Answer: I'm glad you are thinking ahead. An episode of food- borne illness can turn a picnic into an unpleasant event.

More than 25 percent of the food-borne illnesses reported to the federal government's Centers for Disease Control are caused by Salmonella. This bacterium can be present in dairy products, eggs, beef and poultry. Once the tainted food is consumed, the bacterium reproduces inside the body and causes diarrhea, vomiting and fever within eight to 48 hours.

Staphylococcus aureus, another bacterial germ, is the second most common cause of food-borne illness, representing about 15 percent of the total number of cases reported. It is different than Salmonella poisoning in several ways. The illness begins one to eight hours after eating the contaminated food, and the vomiting is more severe and the diarrhea is less intense than in Salmonella poisoning. Also, Staph food poisoning is the result of consuming a poison made by the bacteria rather than as a direct result of an infection with bacteria itself. Your bad picnic experience was probably due to Staph food poisoning, and I can tell you from personal experience that this isn’t a desirable way for turning a pleasant event into a memorable one.

The best way to prevent these bacteria from attacking your food and your family is to keep all foods "cooking hot" (above 140 degrees) or "refrigerator cold" (below 45 degrees) until they are consumed. Transporting your picnic meal in separate insulated containers for hot and cold items should be satisfactory for meals that are to be consumed within four or five hours. For meals that are to be eaten later than this, it is safest to take canned or frozen food and then cook the hot dishes immediately before the meal.

Following these cooking and food handling guidelines is very important because of the ease with which bacterial contamination can start. For instance, a cooked ham can be contaminated with Staphylococcus aureus, a very common bacterium, as the chef puts it in the picnic basket. These bacteria will grow from an almost undetectable level at the time of contamination to produce Staph poisoning that will ruin your picnic as the ham cools over the next several hours. A heavier contamination at the start will speed up the process. So, insulate the ham so it is still "cooking hot" when you eat it, or cool it to "refrigerator cold" immediately after it is cooked.

Other bacteria, viruses, chemicals and parasites can cause food-borne illnesses. To lessen your risk of these, wash your fruits and vegetables at home before you leave on your picnic. It is also wise to take your water with you if the water at the picnic site is of unknown quality.

Question: So, did the mayonnaise actually cause the food poisoning we all had last year?

Answer: I can’t be certain about the cause of last year’s catastrophe, but mayonnaise has gotten an undeserved bad reputation. The most common cause of food poisoning at picnics is actually improperly prepared or stored meats. Potato salad and other foods with mayonnaise can cause food-borne illness, but again, it is usually a problem with preparation or storage temperatures. So, for this summer’s picnics, please follow the simple rule I mentioned earlier: Keep all foods "cooking hot" (above 140 degrees) or "refrigerator cold" (below 45 degrees) until they are consumed. Make your picnic memorable for the pleasant interaction you have with family and friends, not for its aftereffect!

A happy and safe 4th to all my readers!

"Family Medicine" is a weekly column.

To submit questions, write to: John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.

Past columns are available online at http://www.FamilyMedicineNews.org.