Vol. 56, No. 4
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Apr. 1990, p. 877-880
0099-22401901040877-04$02.00/0 Copyright ©) 1990, American Society for Microbiology
Microbiological Quality and Safety of Zoo Foodt EDWARD R. RICHTER* AND IBRAHEEM AL-SHEDDY Department of Food Science and Nutrition, The Ohio State University, 2121 Fyffe Road, Columbus, Ohio 43210 Received 18 October 1989/Accepted 16 January 1990
Two types of commercial products for feeding zoo animals (a frozen meat product, referred to as zoo food, and a dry product, referred to as dry food) were microbiologically examined for spoilage organisms (aerobic, psychrotrophic, coliform, Escherichia coli, mold, and yeasts) and pathogens (Salmonella spp., Listeria monocytogenes, and Campylobacterjejuni). Levels of microorganisms in frozen ground zoo food were compared with those in frozen ground beef and frozen ground turkey meat. The level of microbial contaminants in frozen ground zoo meat was found to be similar to that in frozen ground beef and higher than that in frozen ground turkey meat. Sixty percent of the frozen zoo meat samples were Salmonella positive, and all of the samples were L. monocytogenes positive. Dry zoo food was documented to have microbial levels lower than those in frozen zoo meat; the pathogen levels were 106/g. This level is relatively high, particularly for frozen products, and indicates that if the meat is subjected to temperature abuse, spoilage may occur in short time. The results also reveal that the level of coliform bacteria exceeded 104/g. This large number may result from temperature abuse of the product prior to freezing or from poor sanitation in handling or processing the product. Although some of the enteropathogenic strains of E. coli are MUG negative, the results show that the possiTABLE 1. Microbiological analyses of defrosted zoo food Level of contamination
Analysis"
Time 0 (frozen)
(n 5)
SPCb PBCb
Analyses after 24 h at: 25°C 37C (n =2) (n =2) (n =2)
1o0c
8.6 ± 0.04 6.2 + 0.07 6.4 ± 0.03 7.3 ± 0.17 8.5 ± 0.05 6.6 ± 0.12 7.0 ± 0.09 7.5 ± 0.22 7.8 ± 0.70 Coliforms (VRB)b 4.7 + 0.10 4.8 ± 0.05 5.6 ± 0.01 7.8 ± 0.19 Coliforms (MPN)' 4.9 + 0.11 5.1 ± 0.11 5.7 + 0.31 7.4 ± 0.24 4.7 ± 0.15 4.5 ± 0.42 5.2 ± 0.21 E. colib 4.7 ± 0.16 Yeasts and moldsb 3.9 ± 0.12 4.0 ± 0.07 4.2 ± 0.01 24 ± 4 5.3 ± 1.1 10.0 ± 2 Salmonella spp.' 1,100 + 200 1.5 ± 0.75 0.4 ± 0.3 25 + 5.9 L. monocytogenes' 6.6 ± 1.1
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Apr. 1990, p. 877-880
0099-22401901040877-04$02.00/0 Copyright ©) 1990, American Society for Microbiology
Microbiological Quality and Safety of Zoo Foodt EDWARD R. RICHTER* AND IBRAHEEM AL-SHEDDY Department of Food Science and Nutrition, The Ohio State University, 2121 Fyffe Road, Columbus, Ohio 43210 Received 18 October 1989/Accepted 16 January 1990
Two types of commercial products for feeding zoo animals (a frozen meat product, referred to as zoo food, and a dry product, referred to as dry food) were microbiologically examined for spoilage organisms (aerobic, psychrotrophic, coliform, Escherichia coli, mold, and yeasts) and pathogens (Salmonella spp., Listeria monocytogenes, and Campylobacterjejuni). Levels of microorganisms in frozen ground zoo food were compared with those in frozen ground beef and frozen ground turkey meat. The level of microbial contaminants in frozen ground zoo meat was found to be similar to that in frozen ground beef and higher than that in frozen ground turkey meat. Sixty percent of the frozen zoo meat samples were Salmonella positive, and all of the samples were L. monocytogenes positive. Dry zoo food was documented to have microbial levels lower than those in frozen zoo meat; the pathogen levels were 106/g. This level is relatively high, particularly for frozen products, and indicates that if the meat is subjected to temperature abuse, spoilage may occur in short time. The results also reveal that the level of coliform bacteria exceeded 104/g. This large number may result from temperature abuse of the product prior to freezing or from poor sanitation in handling or processing the product. Although some of the enteropathogenic strains of E. coli are MUG negative, the results show that the possiTABLE 1. Microbiological analyses of defrosted zoo food Level of contamination
Analysis"
Time 0 (frozen)
(n 5)
SPCb PBCb
Analyses after 24 h at: 25°C 37C (n =2) (n =2) (n =2)
1o0c
8.6 ± 0.04 6.2 + 0.07 6.4 ± 0.03 7.3 ± 0.17 8.5 ± 0.05 6.6 ± 0.12 7.0 ± 0.09 7.5 ± 0.22 7.8 ± 0.70 Coliforms (VRB)b 4.7 + 0.10 4.8 ± 0.05 5.6 ± 0.01 7.8 ± 0.19 Coliforms (MPN)' 4.9 + 0.11 5.1 ± 0.11 5.7 + 0.31 7.4 ± 0.24 4.7 ± 0.15 4.5 ± 0.42 5.2 ± 0.21 E. colib 4.7 ± 0.16 Yeasts and moldsb 3.9 ± 0.12 4.0 ± 0.07 4.2 ± 0.01 24 ± 4 5.3 ± 1.1 10.0 ± 2 Salmonella spp.' 1,100 + 200 1.5 ± 0.75 0.4 ± 0.3 25 + 5.9 L. monocytogenes' 6.6 ± 1.1
