Poison by Food

2014, March/ April Adirondac Adirondoc

On a very hot summer afternoon many years ago, I was approached by a fellow camper in the Dix Wilderness. He and some of his group had rather suddenly developed abdominal discomfort and vomiting, which was becoming quite disabling. Based on the history, I was pretty certain that they were suffering from enterotoxin-mediated food poisoning. I gave them some anti-nausea medication, recommended frequent sips of liquids, and got out of the way quickly. As best I know, they recovered uneventfully. (I can’t help but wonder if today someone would have called for urgent evacuation, perhaps by helicopter!)

Food poisoning, a relatively common front country ailment, is fortunately unusual in the backcountry. It can range from an uncomfortable nuisance to a cause of death. Since it is easily prevented, it is a good idea to review it.

There are three basic ways in which our food can cause illness (not including eating too much of it, the major problem). The first of these is by the presence of a natural chemical in the food which causes injury. The best example of this is poisoning by ingestion of some mushrooms, most often of the genus Amanita. These can be overwhelming poisonings, often resulting in liver failure and the need for liver transplantation. The best treatment of this, of course, is prevention. At one point in time, I used to instruct some of my guiding clients on the recognition and preparation of mushrooms in the field. As a rank amateur mycologist, however, I now consider this far too risky.

Serious poisonings can also result from a number of fish, of which ciguatera fish poisoning is the most familiar. Fortunately, these are conditions associated with fish in much warmer climes than that of the Adirondacks.

The second mechanism of food poisoning is that which caused the problem for the campers I introduced earlier. Bacteria (such as Staphylococcus) get into unrefrigerated foods (especially creams, egg products, and the like) and multiply. The bacteria produce a substance (“enterotoxin”) which when ingested produces nausea, vomiting, and cramps within a few hours. Note that it is not the bacteria themselves which are causing the problem, but the toxin they produce. Thus, onset of this illness occurs quickly after ingestion-the bacteria need not multiply in the host.

This is why you probably do not want to sample the cream puffs sitting out at the church picnic in July. Nor do you want to carry egg salad sandwiches in your pack for later consumption. Puddings, cream sauces, and similar delicacies are fine to prepare in the woods-just be sure to eat them completely after preparation. Leftovers are fine if kept in your refrigerator at home, but not in your BRFC in the summer!

The final category of food poisonings results from contamination with microbes which directly cause disease themselves. In these cases, the offending organisms need a period of time to grow and multiply in the intestine before they cause symptoms. Thus, there is an “incubation period” of a few days between ingestion of the food and the development of symptoms.

Many bacteria and viruses can cause this picture. In the U.S., a specific variety of bacteria called E. coli is responsible for particularly severe food poisoning. The condition can progress to kidney failure and death. Although outbreaks have been associated with a host of foods, undercooked ground beef is the most common culprit. There is no such thing as a safe hamburger that is pink in the middle. If you plan to heat up some burgers on a trip, be sure they are well done. Better still, try falafel patties!

The Centers for Disease Control (CDC) has a very helpful website with additional information regarding food-borne illnesses: www.cdc.gov/foodsafety/facts.html# mostcommon.

~Tom Welch, MD, is professor and chair of pediatrics at Upstate Medical University in Syracuse and an active member of the Wilderness Medical Society. He is a licensed professional guide, a certifying instructor for the Wilderness Education Association, and has guided groups in the Adirondacks, Montana, and Alaska. More information is available at his website and blog: www.adirondoc.com. Infectious disease expert Jana Shaw, MD, MPH provided helpful review of this column.

Download PDF

Topics: Diet & Nutrition