323 CUISTRIDXIM PERFRINGENS IN RELATION TO mxr PRODUCTS+ FRANK L. BRYAN Center for Disease Control U.S. Public Health Service Atlanta, Georgia Neat and poultry products, particularly roast beef and turkey, are frequently incriminated as vehicles of Clostridium perfringens foodborne outbreaks (table 1). Such outbreaks are usually associated with foods prepared in food service establishments where large volumes of food are prepered several hours or a day or more in advance of serving and held during the intervening period at temperatures that are conducive t3 germination of spores and multiplication of vegetative cells. Typical outbreaks that have occurred in the United States are illustrated in table 2. Factors, uncovered during epidemic investigations (and indicated in table 2), that contribute to outbreaks of C. perfringens foodborne illness include failure to properly refrigerate cogked foods, holding foods at warm (bacterial incubating) temperatures, preparing foods a day or more in advance of serving, and inadequate reheating (Bryan, 1972). A summary of contributory factors involved in 59 outbreaks is illustrated in table 3. Before these factors can influence growth or survival of C. perfringens in meat, however, the meat must become contamlnated . Clostridium perfringens is a normal inhabitant of the intestinal tract of man and other animals. When enrichment procedures are used, it is not unusual to find all fecal specimens from people and most from animals positive for perfringens. It is also found in high numbers in soil and dust. Data C.on this subject has been reviewed by Smith and Holdeman (1968) and by Bryan (1969). Animal carcasses become contaminated from Fntestinal contents or from soil or dust; in addition, meat can become contaminated when handled by workers. Cross contamination, which is enhanced when both contaminated and uncontaminated meat is processed on the same equipment by the same people, also occurs. As a result of such contemlnation, meat frequently harbors 2. perfringens. Several investigators have reported on the isolation of E. perfringens in various raw meat and poultry products (table 4). These data indicate that -C. perfringens can be expected to be present on raw meat fromtime to time. * Presented at the 25th Annual Reciprocalkat Conference of the American Meat Science Association, 1972. TABU 1. MEAT AND RELATED PRODUCTS WHICH WERF: ATTRIBUTED AS BEING VEHICLES OF OUTBREAKS OF REPOEiTED (CONFIF~IVEDAND UNCONFIRMED) CLOSTRIDIUM PERFmGENS FOODBORNE ILWESS, 1967-1970 Year Food 1967 1968 1969 1970 Total Beef 9 24 34 22 89 Veal 0 0 0 1 1 Pork 1 2 3 1 7 Chicken 3 6 4 2 15 Turkey 1 17 16 13 47 Other meat 2 1 0 2 5 She llf i sh 0 1 1 0 2 Fish 1 1 0 0 2 Other foods 2 5 12 8 27 unknown 5 2 2 5 14 Total 24 59 72 54 209 TABLE 2. REPORTS OF OUTBEiEAKS OF CIOSTRIDIUM PERFRINGENS FOODBORNE ILLNESS THAT HAVE APPEARED IN U.S. LITERATUREL Number Contributory ill Vehicle factors Place References > 20 Creamed chicken, Prepared a day before Restaurants chicken croquettes serving, failure to properly refrigerate cooked foods, inadequate reheating 181 Turkey Prepared a day before Train meal Hart --et al. (1960) serving, failure to properly refrigerate cooked foods, inadequate reheating 40 Meat and chili Failure to properly Picnic Dunham ( 1961) bean combination refrigerate cooked foods 800 to Creamed turkey --- State institution Kemp --et al. (1962) 900 55 Shrimp salad Prepered a day before Sorority house kJebb and Wiley (1962) serving, failure to properly refrigerate cooked foods 34 Roast beef Holding foods at warm Res taurant Hart (1962) temperatures 75 Rmst beef --e Scout dinner :<art (1962) 9 Smoked ham --- Family dinner Sart ( 1962 ) ( c ont hued ) Number Contributory ill Vehicle factors Place Reference 29 Turkey salad Prepared a day before Nursing home Seltzer --et al. (1s2) serving, failure to properly refrigerate cooked foods Creamed chicken Holding foods at 55 warm Church dinner Fleming (m2) temperatures (restaurmt caterer) 155 Roast beef and Prepared a day before Welfare institution Werrin end Witte (1962) gravy serving, failure to luncheon properly refrigerate w cooked foods, inadequate reheating zi: 350 Turkey Prepared a day before School Condit and Proctor (1963) serving, failure to properly refrigerate coDked foods, holding foods at warm temperatures, inadequate reheating 300 Lamb stew pie Leftover food, failure School Agar and Ploeger (1964) to properly refrigerate Nelson --et al. (1966) cooked foods, inadequate reheating Prepared a day before School McCroan and Mixson (1965) serving, failure to properly refrigerate coDked fads (Continued ) TABLE 2. (CONTINUED) Number Contributory ill Vehicle factors Place Reference 171 Turkey a la king Prepared a day before School Herron --et al. (1965) serving, failure to properly refrigerate cooked foods, Wdequate reheating, holding foods at warm temperatures 14 0 Turkey Failure to properly Restaurant banquets Peterson --et al. (1966) refrigerate cooked (three ) foods, inadequate reheating W R) 366 Beef gravy Leftover food, failure School Evans and Preizler (1966) to properly refrigerate Helstad --et el. (1967) cooked foods Chicken salad Prepared a day before Luncheon Goldblatt et al. (1966) 147 serving, failure to properly refrigerate cooked foods 56 Chicken salad --- Luncheon Houglum and Fleming (1967) 784 Prime rib au jus Holding foods at warm Ho te1 banquet Francis --et al. (1968) temperatures Roast beef Contamination by Hot el banquet Schachner et al. 900 L- (1968) equipment after cooking, holding foods at warm temperatures (Continued ) TAELE 2. (CONTINUED) Nmber Contributory ill Vehicle factors Place Reference $00 Mushroom gravy Holding foods at warm Military base Robinson and Meseer (1969) temperatures 76 Braised beef Prepared a day before School Armes --et al. (1%~) serving, failure to properly refrigerate cooked foods, inadequate reheating 590 Turkey with gravy Prepared a day before School Bryan --et al. (1971) serving, failure to w properly refrigerate ?A cooked foods, inadequate reheating N300 Roast beef Holding foods at warm Fast food restaurant Bryan and Kilpatrick (1971) temperatures inadequate reheating 288 Spaghetti and Prepared two days befxe School dinner Deshaye --et al. (1972) meat sauce serving, failure to properly refrigerate cooked foods, inadequate reheating 1 Other outbreaks have been reported to national agencies responsible fw surveillance 3f foodborne diseases. 329 TABLE 3. FACTORS THAT CONTRIBUTE TO OUTBREAKS OF CLQSTRIDIUM PERFRINGENS FOODBOIWE ILLNESS^ Factor Percent Inadequate holding temperature (room, refrigerator, warmer) 100 Failure to properly refrigerate cooked foods 78 Holding foods at warm (bacterial incubating) temperatures 46 Preparing foods a day or more before serving 44 Inadequate reheating of cooked, chilled foods 38 Use of leftover foods 10 1 Based on 59 outbreaks that were reported to the Center for Disease Control from 1961 through 1970. 330 Number of Number Percent samples positive1 positive2 Reference 5 RAW FED MEATS Beef- 50 35 54 13 Frozen bone les s 237 32 Carcasses 47 20 2 1% Imported-Gr . Brit. 134 28 Retail 47 17 Abattoirs 40 2 Steak and mince 10 6 Tripe 6 1H 1N Hamburger -- -- Veal- Carcasses 17 14 10 0 7 1 20 3 2 Frozen boneless 163 Pork- Carcasses 41 15 55 ll Retail 55 27 Abattoirs 14 3 Sausage 21 10 38 36 fl 9N 1 Lamb and Mutton Carcasses 27 14 23 1 17 0 Imported-Gr . Brit. 74 li3 Abattoir 19 12 Frozen boneless 163 2 Liver Market 100 26 Abattoir 100 12 Hospital 2 1 Black pudding 4 2 ‘1’ABI;E 4. (CONTINUED) Number of Number Percent Food samples positive’ positive2 Reference5 POULTRY 26 15 58 7 6H 86 3N 44 1 Chicken (14) 25 10 40 Turkey 24 10 42 35 7 20 17 FISH 18 11 H 61 3N 17 Herring 14 a 58 100 1 1 MEAT, POULTFX, FISH 122 20 16 (no breakdown ) 1 H = hemolytic; N = non-hemolytic. ( ) = heat-resistant strains; percentages are least sigpificant because both heat-sensitive and heat-resistant strains cause foodborne illness. 3 Without enrichment. Enrichment method. 5 [l]Hall and Angelotti (1965); [21 Hobbs et al. (1953); [3] Hobbs and Wilson (1957); [41 Bryan and Kilpatrick (s’fii;[51 Sylvester and Green (1961); [61 McKillop (1959); E71 Messer et al. (1970); [81 Canada and (1964); [91 Bryan and McKinley (lE2x [lo] Zottola and Busta ; ill1 Christian and King (1971); [I21 Strong --et al. (1963). 332 It should also not be surprising to find C. perfringens In cooked meat and poultry products because its spore8 are present on the raw products and these cpores can survive the heat generated during ordinary cooking procedures and because recontamination from workers or from equipment that contact cooked meat is a likely possibility (Bryan and Kilpatrick, 1971). Several investigators have found C. perfringens in cooked meat and poultry products (table 5). "hue, if such-cooked products are held at temperatures that do not prevent the gruwth of C. perfringens, spores will germinate and vegetative cells will multiply; if gicn enough time, numbers sufficient to cause illness will develop. By serotyping isolates from raw and cooked meat and from kitchen equipment, evidence shows that strains of C. perfringens present on raw meat or inserted into the meat by thermopgs survived cooking and can be found on or in cooked meat. Also, workers can be the source of the serotypes present on cooked, sliced meat (Bryan and Kilpatrick, 1971). Several factors permit the development of large numbers of perfringens in cooked meat and poultry products: C. 1. It requires several amino acids (arginine, leucine, isoleucine, methionine, phenylalanine, threonine, valine, tryptophane, histidine, cysthe, glutamic acid, tyrosine, aspartic acid, and s3me strains serine and alanine) and several vitambs (adenine, biotin, nicoti- namide, pantothenate, pyridoxal, and some strains riboflavin and uracil) for growth (Boyd --et al., 1948; Fuchs and Bonde, 1957). Foods that do not contain these amino acids and vitamins are not suitable for its growth.