Taken from the Center for Disease Control's publication, Morbidity and
Mortality Weekly Report. I particularly like the section "The black pepper
came from a can labeled 'black pepper' that he had found 6 weeks before the
lunch in the truck of a deceased relative."
Submitted by Christopher Gray
BEGIN
Aldicarb as a Cause of Food Poisoning -- Louisiana, 1998
Cholinesterase-inhibiting pesticides (i.e., organic phosphates and
carbamates), widely used in agriculture, can cause illness if they
contaminate food or drinking water. Aldicarb, a regulated carbamate
pesticide, is highly toxic, and the U.S. Environmental Protection Agency
(EPA) requires applicators to be trained and certified. This report
describes a foodborne outbreak of aldicarb poisoning that occurred when
improperly stored and labeled aldicarb was used mistakenly in food
preparation.
On July 19, 1998, 20 employees attended a company lunch prepared from
homemade foods. Shortly after eating, several persons developed neurologic
and gastrointestinal symptoms. Ten visited a hospital emergency department,
and two were hospitalized. On July 20, a hospital infection-control nurse
reported the incident to the Louisiana Office of Public Health, which then
investigated the outbreak.
Investigators interviewed all 20 lunch participants about illness and
foods eaten during the meal; 14 (70%) reported gastrointestinal or
neurologic symptoms. The most common gastrointestinal symptoms were
abdominal cramps (13 [93%]), nausea (13 [93%]), and diarrhea (12 [86%]).
Neurologic symptoms included dizziness (13 [93%]), sweating (12 [86%]),
muscle fasciculations (12 [86%]), eye twitching (eight [57%]), and blurred
vision (six [43%]). Illness lasted a median of 4 hours (range: 1-8 hours).
Median time between ingestion of food and onset of symptoms was 45 minutes
(range: 40 minutes-3 hours). The heart rate of one of the two persons
hospitalized was 20 beats per minute on arrival at the emergency department,
but his heart rate increased after treatment with atropine. The second
person was hospitalized for an increased and irregular heart beat that
responded to treatment with digitalis.
The lunch consisted of pork roast, boiled rice, cabbage salad,
biscuits, and soft drinks. Only the cabbage salad was associated with
illness. Of the 16 persons who ate the cabbage salad, 14 became ill (attack
rate: 88%); the four persons who had not eaten the cabbage salad did not
develop symptoms (attack rate: 0%, p=0.003, Fisher's exact test).
The employee who prepared the cabbage salad reported mixing two 1-lb
bags of precut, prepackaged cabbage in a bowl with vinegar and ground black
pepper. The black pepper came from a can labeled "black pepper" that he had
found 6 weeks before the lunch in the truck of a deceased relative. This
black pepper had not been used by the employee for food preparation before
the company lunch. The cabbage salad was prepared the night before the lunch
and stored in the refrigerator until it was brought to work and served at
approximately 11 a.m.
The contents of the black pepper container were tested for
organophosphate and carbamate pesticides. High-performance liquid
chromatography identified the granules in the container as 13.7% aldicarb,
the pesticide TEMIK[Registered] 15G*. A 6-g portion of cabbage salad
contained 272.6 parts per million (ppm) of aldicarb.
The deceased owner of the pepper can had been a crawfish farmer. After
its investigation, the Louisiana Department of Agriculture and Forestry
believed the crawfish farmer had used aldicarb on bait to prevent
destruction of his crawfish nets, ponds, and levees by wild dogs and
raccoons. The source of the TEMIK[Registered] 15G could not be determined
despite the department's extensive traceback effort.
Reported by: TA Farley, MD, L McFarland, DrPH, State Epidemiologist,
Infectious Disease Epidemiology Section, Louisiana Dept of Health and
Hospitals; J McClelland, Louisiana Dept of Agriculture. Health Studies Br,
Div of Environmental Hazards and Health Effects, National Center for
Environmental Health; Div of Applied Public Health Training, Epidemiology
Program Office; and an EIS Officer, CDC.
Editorial Note: Aldicarb (2-methyl-2-[methylthio] propionaldehyde
O-[methylcarbamoyl] oxime) is one of the most potent pesticides used in the
United States. It is absorbed rapidly through the gut and, in liquid form,
through intact skin (1). As a cholinesterase inhibitor, it increases
parasympathetic nervous system activity. Common symptoms of poisoning
include malaise, dizziness, sweating, nausea, diarrhea, and muscle weakness;
blurred vision and muscle spasms also can occur. EPA has placed aldicarb in
its highest acute toxicity category.
Aldicarb is classified as a restricted-use pesticide and can be sold to
and applied by trained certified applicators only. Applicators are required
to wear personal protective equipment (i.e., coveralls, waterproof gloves,
chemical-resistant footwear and headgear, and protective eyewear). In cases
of aldicarb poisoning, atropine sulfate is the antidote of choice and can be
supplemented by treatment of symptoms and rapid removal of the toxin (e.g.,
by induced vomiting) (2).
The 272.6 ppm of aldicarb found in a 6-g cabbage salad sample was
enough to be toxic to humans. Each person who had eaten the salad would have
consumed approximately 17 mg of aldicarb if equal amounts of salad had been
eaten. A 150-lb (70-kg) adult would have ingested 0.2 mg of aldicarb per kg
of body weight, nearly 10 times the lowest observed effect level for
subclinical blood cholinesterase depression (0.025 mg per kg body weight).
Blood levels as low as 0.0011 mg per kg body weight have been associated
with poisoning in humans (3). In addition, cabbage and vinegar, both acidic
substances, are less effective than alkaline substances at breaking down
aldicarb to less toxic chemical compounds.
In addition to occupational exposures (4), aldicarb poisoning has
resulted from unintentional or suicidal ingestion of aldicarb illegally used
as a rodenticide (5) and from eating contaminated watermelons (6,7) and
cucumbers (7). The largest pesticide-related foodborne outbreak in the
United States occurred in 1985 when 1373 persons reported becoming ill after
eating watermelons grown in soil treated with aldicarb; 78% of these persons
had probable or possible pesticide-related illnesses (6). The median amount
of aldicarb sulfoxide eaten per person in that outbreak was approximately
0.027 mg per kg body weight (8). Aldicarb residues have been detected in
ground water and drinking water wells (9), but studies of the clinical
implications of these exposures have been inconclusive (10). EPA has
developed tolerance levels for aldicarb residues on food or animal feed and
a maximum contaminant level for aldicarb in drinking water (0.003 mg/L).
END
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