DETECTION OF STAPHYLOCOCCAL ENTEROTOXIN IN FOOD

Methods are described for the extraction and serological detection of trace amounts of enterotoxins A and B in foods incriminated in outbreaks of staphylococcal food poisoning. Evidence is presented for the probable applicability of the methods for the detection of unidentified enterotoxins.

ACUTE AND CHRONIC ENTEROTOXIN ENTERITIS

1. Dogs develop severe gastrointestinal symptoms in response to intraintestinal administration of staphylococcal enterotoxin. These symptoms are salivation, vomiting, and diarrhea. 2. Staphylococcal enterotoxin induces acute enteritis marked by edema, hyperemia, round cell infiltration, mucosal exudation, and destruction of intestinal villi. 3. Prolonged administration of enterotoxin into the lumen of the intestine produced thickening of the entire bowel wall, edema, dilatation of the lymphatics, and exaggeration of submucous lymphoid nodules. The hypertrophy of the lymphoid nodules is visible, in the gross, as enlarged longitudinal mucosal ridges. This abnormality is arranged in skip areas, not dissimilar to those observed in human regional enteritis. 4. Chronic enterotoxin enteritis is associated with mesenteric lymph node hypertrophy. 5. The intestinal mucosa shows minute ulcerations, loss of villi, submucous fibrosis, and evidence of chronic inflammation.

OCCURRENCE OF COAGULASE-POSITIVE STAPHYLOCOCCI IN CHEDDAR CHEESE

Samples (13) from several lots of cheddar cheese incriminated in staphylococcal food poisoning and 343 samples of cheddar cheese purchased over a 3-year period in retail markets were examined quantitatively for coagulase-positive staphylococci with the smear plate technique. Of the food-poisoning samples, 11 contained coagulase-positive staphylococci in numbers that ranged from 50 to several million per g. Of the 343 market cheese samples, 20% contained coagulase-positive staphylococci in concentrations ranging from less than 50 to more than 200,000 per g. The phage patterns of 64 of 89 cultures isolated from the food-poisoning samples placed them in the miscellaneous phage group (44A) or in phage group IV and the miscellaneous group (42D/44A); 14 had phage patterns that involved group III, the group with which food poisoning has usually been associated. In contrast, over 50% of 104 cultures from the market cheese, which were typed at 100 times the critical test dilution, had phage patterns that involved group III. Of nine selected cultures isolated from the food-poisoning cheese, three (all in phage group III) were positive for enterotoxin by intravenous injection test of cats.

CLOSTRIDIUM PERFRINGENS TYPE C ENTEROTOXEMIA OF THE NEWBORN PIG

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