Agriculture Reference
In-Depth Information
Salmonella and Listeria . To answer these concerns and
in an attempt to improve meat safety, the United States
Department for Agriculture (USDA) Food Safety
Inspection Service (FSIS) suggests that all carcases
must receive at least one antimicrobial treatment before
chilling. These treatments may include hot water,
organic acid sprays, antimicrobials, hydrogen peroxide,
trisodium phosphate (TSP) and chlorinated water.
European food law permits potable water and approved
substances only.
Smokies
Within the United Kingdom, there is a market, especially
among recent immigrants from West Africa and parts of Asia,
for smoked skin-on sheep meat, known colloquially as
'smokies'.
The production process involves the slaughtering of sheep
that have been recently shorn, to a wool length of about
5 mm. Following shackling and bleeding, the carcase is
singed and then pressure washed to remove the burnt wool
and expose the golden brown, smoked sheep skin. Following
evisceration and removal of the head and, if necessary, the
spinal cord as specified risk material (SRM), the carcase is
inspected before undergoing a final 'toasting' to dry the
carcase surface and produce an even golden brown colour.
A microbiological study of the surface of the carcase
indicated that the 'smokies' had lower total aerobic
microbiological counts than conventionally dressed sheep
carcases. As the presence of the skin might hinder visual
inspection of the surface of the carcase for the presence of
abscesses, additional palpation, especially of the neck region,
might be appropriate.
Investigations into the potential for residues of veterinary
medicinal products, particularly subcutaneously administered
vaccines, anthelmintics and topically applied sheep scab
treatments, confirmed that existing controls on the use of
authorised veterinary medicines would in all likelihood
provide adequate consumer protection. Similarly, concerns
that residues of potentially genotoxic and/or carcinogenic
polycyclic hydrocarbons might be present from the smoking
process on the carcase at harmful levels proved to be
unfounded.
Water
Historically it was not uncommon to wash the carcases
of both cattle and sheep with large volumes of hot or
cold water to remove any visible contamination which
had found its way on to the carcase during processing.
The general movement in Europe has been away from
this practice towards the use of the minimal amount of
water necessary to remove bone dust from the spinal
column, with faecal and other contamination being
removed by trimming. This approach was supported by
a great deal of scientific research and comment, such as
that of Ellerbroek, Wegener and Arndt (1993), who
demonstrated that spray washing did not reduce or
increase bacterial contamination of the ventral area of
sheep carcases, the portion of the carcase most likely to
be contaminated by slaughter personnel, but led to bac-
terial contamination of the clean dorsal surface of the
carcase. The conclusion was therefore drawn that spray
washing with water at 12°C, 6 bar pressure for 20 sec-
onds did not improve the microbial status of sheep car-
cases and that the additional water remaining on the
carcase enhanced the multiplication of bacteria in the
long run.
Having reviewed the available evidence, Gill (2009)
concluded that when carcases or sides are relatively
heavily contaminated during skinning or subsequent
operations, washing for relatively long times will sub-
stantially reduce the numbers of bacteria on the meat,
probably by removing bacteria that are associated with
particles that are flushed from the carcases or sides.
However, if the contamination of carcases is well con-
trolled throughout the dressing process, washing will
have little or no beneficial effect on the microbiological
condition of the meat.
Studies suggest that to have any beneficial effect, large
volumes of water are required to flush contaminants
from the surface of the carcase or the temperature of the
water must be high enough, and the contact time long
enough, to cause heating of the surface of the meat suf-
ficient to kill the specific bacteria being measured.
The Food Safety and Inspection Service of the USDA
has approved two novel methods of cleansing beef
As in cattle, bunging of pigs can be improved by
automation. A device with a tubular blade is positioned
by a central pin which is placed up the rectum. The blade
cuts down around the rectum, loosening it.
No attempt is usually made to seal the porcine
oesophagus.
post-slaughter decontamination
The emergence of E. coli O157: H7, especially in
Canada, the United States and Scotland, as a significant
food poisoning pathogen of animal origin has initiated
a search for methods by which the consumer can be
given even greater assurances as to the safety of the
meat to be consumed. The deaths of children and the
elderly during the 1990s who had consumed beef burg-
ers or meat products contaminated with low numbers
of the O157: H7 organisms have caused understandable
anxiety especially as it followed upon increased public
concern about other food poisoning organisms such as
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