Fresh Meats and Poultry
69
strains then cooked and stored for up to 14 days under vacuum at 4
◦ C, the inoculated cells showed
a slight decline and remained essentially unchanged as product temperature decreased from 54.5 to
7.2
◦ C.
173 The significance of this organism in foods is discussed in Chapter 24.
Some members of the family Enterobacteriaceae have been found to be common in fresh and frozen
beef, pork, and related meats. Of 442 meat samples examined by Stiles and Ng,
169 86% yielded
enteric bacteria, with all 127 ground beef samples being positive. The most frequently found were
Escherichia coli biotype I (29%), Serratia liquefaciens (17%), and Pantoea agglomerans (12%). A total
of 721 isolates (32%) were represented by Citrobacter freundii, Klebsiella pneumoniae, Enterobacter
cloacae, and E. hafniae. In an examination of 702 foods for fecal coliforms by the most-probablenumbers (MPN) method representing 10 food categories, the highest number was found in the 119
ground beef samples, with the geometric mean by the AOAC (Association of Official Analytical
Chemists) procedure being 59/g.
3 The mean number for 94 pork sausage samples was 7.9/g. From
32 samples of minced goat meat, the mean coliform, Enterobacteriaceae, and APC counts were,
respectively, 2.88, 3.07, and 6.57 log 10 .
131 More information on the incidence/prevalence of coliforms,
enterococci, and other indicator organisms can be found in Chapter 20.
From the 563 samples of ground beef examined in the United States as noted above, 53% contained C. perfringens and 30% S. aureus.
176 Using a nested polymerase chain reaction (PCR) assay,
enterotoxigenic Clostridium perfringens was found in 2%, 12%, and 0% of 50 beef, chicken, and pork
samples, respectively, in Japan.
128
A study of 470 fresh sheep carcasses in Australia found the mean APC (determined at 25
◦ C after 72
hours) to be 3.92 log 10 /cm
2 and 3.48 log 10 /cm
2 when determined at 5
◦ C after a 14-day incubation.
179
For a more extensive coverage of Gram-positive bacteria in meats, see reference 87.
Escherichia coli (Biotype I)
This bacterium is the most widely used as an indicator of the sanitary state of fresh foods, and it along
with other indicator organisms is defined and discussed in Chapter 20. An international committee has
stressed the desirability of testing for indicator organisms rather than specific pathogens in assessing
the safety of beef.
17 Some findings of this organism in fresh meats are summarized below.
In a study of frozen beef patties in the United States, the mean aerobic plate count (APC) was <3.0
log 10 cfu/g, and coliforms and E. coli biotype I were <1.0 log 10 cfu/g.
144 These investigators noted a
lack of correlation between low numbers of E. coli biotype I and E. coli 0157:H7. A Canadian study
found that coliforms and E. coli recovered from the table top and conveyor belt in a meat processing
facility were comparable to those recovered from beef cuts and sides, which emphasizes the importance
of conveying equipment as sources of these organisms to beef cuts.
70
The incidence and prevalence of biotype I strains of E. coli vary widely among retail or finished
red meats. From 470 sheep carcasses studied in Australia, 75% contained this organism
181 while from
812 Australian beef carcasses processed for export only, 11% were positive.
141 In the United States,
E. coli was recovered from 25% of 404 ground beef samples;
186 from 30% of 100 postexsanginated
pork carcasses; and from 30% of the chilled carcasses tested.
172
Arcobacter and Campylobacter spp.
These genera are closely related phylogenetically, and it is not surprising that they share common
habitats. Summaries of their incidence and prevalence in a variety of meats and poultry are presented
in Table 4–4. In general, Arcobacter spp. appear to be more common among poultry than red meat
products, and this is true for Campylobacter spp. A. butzleri is common, and it was found on all 25
69
strains then cooked and stored for up to 14 days under vacuum at 4
◦ C, the inoculated cells showed
a slight decline and remained essentially unchanged as product temperature decreased from 54.5 to
7.2
◦ C.
173 The significance of this organism in foods is discussed in Chapter 24.
Some members of the family Enterobacteriaceae have been found to be common in fresh and frozen
beef, pork, and related meats. Of 442 meat samples examined by Stiles and Ng,
169 86% yielded
enteric bacteria, with all 127 ground beef samples being positive. The most frequently found were
Escherichia coli biotype I (29%), Serratia liquefaciens (17%), and Pantoea agglomerans (12%). A total
of 721 isolates (32%) were represented by Citrobacter freundii, Klebsiella pneumoniae, Enterobacter
cloacae, and E. hafniae. In an examination of 702 foods for fecal coliforms by the most-probablenumbers (MPN) method representing 10 food categories, the highest number was found in the 119
ground beef samples, with the geometric mean by the AOAC (Association of Official Analytical
Chemists) procedure being 59/g.
3 The mean number for 94 pork sausage samples was 7.9/g. From
32 samples of minced goat meat, the mean coliform, Enterobacteriaceae, and APC counts were,
respectively, 2.88, 3.07, and 6.57 log 10 .
131 More information on the incidence/prevalence of coliforms,
enterococci, and other indicator organisms can be found in Chapter 20.
From the 563 samples of ground beef examined in the United States as noted above, 53% contained C. perfringens and 30% S. aureus.
176 Using a nested polymerase chain reaction (PCR) assay,
enterotoxigenic Clostridium perfringens was found in 2%, 12%, and 0% of 50 beef, chicken, and pork
samples, respectively, in Japan.
128
A study of 470 fresh sheep carcasses in Australia found the mean APC (determined at 25
◦ C after 72
hours) to be 3.92 log 10 /cm
2 and 3.48 log 10 /cm
2 when determined at 5
◦ C after a 14-day incubation.
179
For a more extensive coverage of Gram-positive bacteria in meats, see reference 87.
Escherichia coli (Biotype I)
This bacterium is the most widely used as an indicator of the sanitary state of fresh foods, and it along
with other indicator organisms is defined and discussed in Chapter 20. An international committee has
stressed the desirability of testing for indicator organisms rather than specific pathogens in assessing
the safety of beef.
17 Some findings of this organism in fresh meats are summarized below.
In a study of frozen beef patties in the United States, the mean aerobic plate count (APC) was <3.0
log 10 cfu/g, and coliforms and E. coli biotype I were <1.0 log 10 cfu/g.
144 These investigators noted a
lack of correlation between low numbers of E. coli biotype I and E. coli 0157:H7. A Canadian study
found that coliforms and E. coli recovered from the table top and conveyor belt in a meat processing
facility were comparable to those recovered from beef cuts and sides, which emphasizes the importance
of conveying equipment as sources of these organisms to beef cuts.
70
The incidence and prevalence of biotype I strains of E. coli vary widely among retail or finished
red meats. From 470 sheep carcasses studied in Australia, 75% contained this organism
181 while from
812 Australian beef carcasses processed for export only, 11% were positive.
141 In the United States,
E. coli was recovered from 25% of 404 ground beef samples;
186 from 30% of 100 postexsanginated
pork carcasses; and from 30% of the chilled carcasses tested.
172
Arcobacter and Campylobacter spp.
These genera are closely related phylogenetically, and it is not surprising that they share common
habitats. Summaries of their incidence and prevalence in a variety of meats and poultry are presented
in Table 4–4. In general, Arcobacter spp. appear to be more common among poultry than red meat
products, and this is true for Campylobacter spp. A. butzleri is common, and it was found on all 25