572 Modern Food Microbiology
endospores, and when the food is cooled and rewarmed, the endospores germinate and grow. Meat
dishes are most often the cause of this syndrome, although nonmeat dishes may be contaminated by
meat gravy. The greater involvement of meat dishes may be due in part to the slower cooling rate
of these foods and also to the higher incidence of food-poisoning strains in meats. Strong et al.
114
found the overall incidence of the organism to be about 6% in 510 American foods. The incidence for
various foods was 2.7% for commercially prepared frozen foods; 3.8% for fruits and vegetables; 5%
for spices; 1.8% for home-prepared foods; and 16.4% for raw meat, poultry, and fish. Hobbs et al.
50
found that 14–24% of veal, pork, and beef samples examined contained heat-resistant endospores,
but all 17 samples of lamb were negative. In Japan, enterotoxigenic strains were recovered from food
handlers (6% of 80), oysters (12% of 41), and water (10% of 20 samples).
100 More recently, only
ca. 1.4% of cpe-positive isolates were detected in ca. 900 non-outbreak retail foods in the United
States.
124
An outbreak of food poisoning involving 375 persons where 140 became ill was found to be caused
by both C. perfringens and Salmonella Typhimurium.
94 C. perfringens has been demonstrated to grow
in a large number of foods. A study of retail, frozen precooked foods revealed that half were positive for
vegetative cells, and 15% contained endospores.
121 The latter investigators inoculated meat products
with the organism and stored them at t29
◦ C for up to 42 days. Although spore survival was high,
vegetative cells were virtually eliminated during the holding period. The survival of inoculated cells
in raw ground beef was studied by Goepfert and Kim,
39 who found decreased numbers upon storage
at temperatures between 1
◦ C and 12.5
◦ C. The raw beef contained a natural biota, and the finding
suggests that C. perfringens is unable to compete under these conditions.
Prevention
The C. perfringens gastroenteritis syndrome may be prevented by proper attention to the leading
causes of food poisoning of all types noted in previous chapters. Because this syndrome often occurs in
institutional cafeterias, some special precautions should be taken. Upon investigating a C. perfringens
food-poisoning outbreak in a school lunchroom in which 80% of students and teachers became ill,
Bryan et al.
16 constructed a time–temperature chart in an effort to determine when, where, and how the
turkey became the vehicle (Figure 24–2). It was concluded that meat and gravy, but not dressing, were
responsible for the illness. As a means of preventing recurrences of such episodes, these investigators
suggested nine points for the preparation of turkey and dressing:
1. Cook turkey until the internal breast temperature reaches at least 165
◦ F (74
◦ C), or preferably
higher.
2. Thoroughly wash and sanitize all containers and equipment that previously had contact with raw
turkey.
3. Wash hands and use disposable plastic gloves when deboning, deicing, or otherwise handling
cooked turkey.
4. Separate turkey meat and stock before chilling.
5. Chill the turkey and stock as rapidly as possible after cooking.
6. Use shallow pans for storing stock and deboned turkey in refrigerators.
7. Bring stock to a rolling boil before making gravy or dressing.
8. Bake dressing until all portions reach 165
◦ F or higher.
9. Just prior to serving, heat turkey pieces submerged in gravy until largest portions of meat reach
165
◦ F.
endospores, and when the food is cooled and rewarmed, the endospores germinate and grow. Meat
dishes are most often the cause of this syndrome, although nonmeat dishes may be contaminated by
meat gravy. The greater involvement of meat dishes may be due in part to the slower cooling rate
of these foods and also to the higher incidence of food-poisoning strains in meats. Strong et al.
114
found the overall incidence of the organism to be about 6% in 510 American foods. The incidence for
various foods was 2.7% for commercially prepared frozen foods; 3.8% for fruits and vegetables; 5%
for spices; 1.8% for home-prepared foods; and 16.4% for raw meat, poultry, and fish. Hobbs et al.
50
found that 14–24% of veal, pork, and beef samples examined contained heat-resistant endospores,
but all 17 samples of lamb were negative. In Japan, enterotoxigenic strains were recovered from food
handlers (6% of 80), oysters (12% of 41), and water (10% of 20 samples).
100 More recently, only
ca. 1.4% of cpe-positive isolates were detected in ca. 900 non-outbreak retail foods in the United
States.
124
An outbreak of food poisoning involving 375 persons where 140 became ill was found to be caused
by both C. perfringens and Salmonella Typhimurium.
94 C. perfringens has been demonstrated to grow
in a large number of foods. A study of retail, frozen precooked foods revealed that half were positive for
vegetative cells, and 15% contained endospores.
121 The latter investigators inoculated meat products
with the organism and stored them at t29
◦ C for up to 42 days. Although spore survival was high,
vegetative cells were virtually eliminated during the holding period. The survival of inoculated cells
in raw ground beef was studied by Goepfert and Kim,
39 who found decreased numbers upon storage
at temperatures between 1
◦ C and 12.5
◦ C. The raw beef contained a natural biota, and the finding
suggests that C. perfringens is unable to compete under these conditions.
Prevention
The C. perfringens gastroenteritis syndrome may be prevented by proper attention to the leading
causes of food poisoning of all types noted in previous chapters. Because this syndrome often occurs in
institutional cafeterias, some special precautions should be taken. Upon investigating a C. perfringens
food-poisoning outbreak in a school lunchroom in which 80% of students and teachers became ill,
Bryan et al.
16 constructed a time–temperature chart in an effort to determine when, where, and how the
turkey became the vehicle (Figure 24–2). It was concluded that meat and gravy, but not dressing, were
responsible for the illness. As a means of preventing recurrences of such episodes, these investigators
suggested nine points for the preparation of turkey and dressing:
1. Cook turkey until the internal breast temperature reaches at least 165
◦ F (74
◦ C), or preferably
higher.
2. Thoroughly wash and sanitize all containers and equipment that previously had contact with raw
turkey.
3. Wash hands and use disposable plastic gloves when deboning, deicing, or otherwise handling
cooked turkey.
4. Separate turkey meat and stock before chilling.
5. Chill the turkey and stock as rapidly as possible after cooking.
6. Use shallow pans for storing stock and deboned turkey in refrigerators.
7. Bring stock to a rolling boil before making gravy or dressing.
8. Bake dressing until all portions reach 165
◦ F or higher.
9. Just prior to serving, heat turkey pieces submerged in gravy until largest portions of meat reach
165
◦ F.