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Food Protection Trends
Abstracts - November 2004
Potential for Use of Hide-Carcass Microbial Counts
Relationship as an Indicator of Process Hygiene Performance of Cattle Abattoirs
Restaurant-associated Outbreak Possibly Linked to
Methomyl Poisoning, Ohio, 2000
Potential for Use of Hide-Carcass
Microbial Counts Relationship as an Indicator of Process Hygiene Performance
of Cattle Abattoirs
LUIS VIVAS ALEGRE and SAVA BUNCIC*
Division of Farm Animal Science, School of Veterinary Science, University of
Bristol, Langford, Bristol BS40 5DU, United Kingdom
SUMMARY
At a large, modern abattoir (A), thirty-one visually clean beef cattle were
slaughtered. Before skinning, whole brisket areas of hide of twenty-nine animals
were surface contaminated with a 24-hour broth culture of Escherichia
coli (K12), by use of a brush, so as to obtain animals with higher microbial
levels on hides. The remaining two animals were not contaminated, because of
time constraints. At a small, traditional abattoir (B), thirty-one visually
clean beef cattle, the hides of which were not artificially contaminated, were
slaughtered, so as to obtain animals with lower microbial levels on hides. At
both abattoirs, from each animal, three samples (5 cm2 each) from the brisket
area were taken by excision from: a) hide before skinning, b) carcass halfway
through skinning, and c) final dressed carcass. In each sample, total count
of bacteria (TVC) and Enterobacteriaceae count (EC) per cm2 were determined. The process
hygiene performance of each abattoir was assessed by three methods. First, the
official UK Hygiene Assessment System (HAS) scoring was conducted by official
veterinarians, based on observational assessment (scoring) of the degree of
the abattoir’s operation compliance with recognized best hygiene practice. Second,
the EU microbiological criteria (TVC and EC) were used for final carcasses.
Third, newly proposed bacterial output/input factor (BOIF), based on calculation
of TVC or EC counts on final dressed carcasses as a proportion of corresponding
values on hides before dressing, was used. At abattoir A, final carcasses had
higher microbial counts than at abattoir B, due to the much higher microbial
levels on artificially contaminated hides. Based on the EU microbiological criteria
for final carcasses, therefore, process hygiene performance of abattoir B would
be judged better than that of A. However, hygiene performance was better
for abattoir A than for B, when either the HAS or the BOIF method was applied.
Among the three methods, the BOIF appeared most appropriate for between-abattoir
comparison of process hygiene, because it can, and the other two cannot, indicate
what proportion of the microbial load on hides is transferred onto corresponding
carcasses.
Restaurant-associated Outbreak
Possibly Linked to Methomyl Poisoning, Ohio, 2000
Mark E Beatty,1,2* Kathy Cowen,3 Elizabeth Hoffman,3 Teresa
Long,3 Mary Parrish,4
Ron Genevie,4 Forrest Smith,4 Alden Henderson,5 John Barr,5 and Sonja J. Olsen,2
1-Epidemic Intelligence Service,
Division of Applied Public Health Training, Epidemiology Program Office, Centers
for Disease Control and Prevention, Atlanta, GA, USA;
2-Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic
Diseases, National Center for Infectious Diseases, Centers for Disease Control
and Prevention, Atlanta, GA, USA;
3-City of Columbus Health Department, Columbus, OH, USA;
4-Ohio Department of Health, Columbus, OH, USA;
5-National Center for Environmental Health, Centers for Disease Control
and Prevention, Atlanta, GA, USA
SUMMARY
Sixty-eight
percent of foodborne outbreaks reported to CDC each year have no etiology
identified. A subset of these is
comprised of outbreaks with rapid onset and short duration.
Differences exist in the identification of the cause of these outbreaks
from traditional foodborne outbreaks. This
study examined a foodborne outbreak associated with the carbamate pesticide
methomyl at a restaurant in Columbus, Ohio, during October 2000.
We conducted a case-control study and targeted laboratory testing of
clinical and food specimens. We
identified 25 patients and 48 controls. The
most common symptoms were nausea (84%) and vomiting (52%).
The median incubation period was 30 minutes. The house salad was statistically implicated (Odds Ratio =
8.9; 95% Confidence Interval =1.1–198). Methomyl
was detected in two salad samples and an ill patron’s vomitus.
Methomyl-containing fly bait was in use at the restaurant.
In summary, a salad contaminated with methomyl likely caused an outbreak
of gastrointestinal illness with rapid onset and short duration.
Identifying the cause of foodborne chemical outbreaks depends on early
suspicion, collection of appropriate specimens, and laboratory procedures that
detect a range of likely agents.
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