43Chapter 3
Meat Decontamination
Panagiotis N. Skandamis , George - John E. Nychas , and John N. Sofos
Introduction
Food animals, whether infected or asymp-
tomatic carriers, are sources of spoilage and
pathogenic microorganisms. More specifi -
cally, animals carry microorganisms on their
external surfaces, including the gastrointes-
tinal tract, which contaminate the environ-
ment as well as food and water, forming a
complete cycle. In general, external animal
surfaces, as well as their feces and the envi-
ronment, may serve as sources of contamina-
tion for: (i) carcasses during the slaughtering,
dressing, chilling, and cutting processes; (ii)
meat products during processing, storage and
handling; (iii) water and other foods through
contaminated manure; or (iv) direct transfer
and infection of humans (Sofos 2002 ). More
specifi cally, sources of microbial contamina-
tion for meat include air, water, feces, knives
used during exsanguination and cutting,
hides, fl eece, feathers, the gastrointestinal
tract through accidental spillage of its con-
tents during evisceration, and lymph nodes if
inspected by incision or otherwise cut.
Furthermore, contact with other carcasses,
employees, as well as the processing envi-
ronment (e.g., equipment, water, or air) may
also contribute to carcass and meat contami-
nation (Sofos 1994, 2002 ; Sofos et al. 1999a,
b, c ; Elder et al. 2000 ; Childs et al. 2006 ).
Although multiple species of microorgan-
isms may be introduced onto the carcass
during hide removal (Bell 1997 ), the major-
ity of these microorganisms consist of non-
pathogenic spoilage bacteria and indicator
microorganisms, such as coliforms and
Escherichia coli (at levels 10 to 10^7 CFU/cm^2
or higher). However, there is also a potential
for contamination with pathogens such as
Escherichia coli O157:H7, Salmonella ,
Campylobacter spp., and others (Gill and
Bryant 1992 ; Sofos et al. 1999a ; Bacon et al.
2000 ; Reid et al. 2002 ; Koutsoumanis and
Sofos 2004 ; Koutsoumanis et al. 2006 ).
Reduction of pathogen contamination
levels in meat products could reduce the
burden of food - borne diseases, and thus,
decrease the estimated $12 billion annual
economic losses in medical costs, lost pro-
ductivity, recalls, legal fees, and loss of busi-
nesses in the United States (Buzby et al.
1996 ; Stopforth and Sofos 2005 ). Therefore,
there is increased interest in improving the
microbiological status of meat. The Food
Safety and Inspection Service (FSIS) of the
United States Department of Agriculture
(USDA) has declared E. coli O157:H7 an
“ adulterant ” in ground beef and other nonin-
tact beef products and has issued a zero -
tolerance policy that requires removal of all
visible contamination, including feces,
ingesta, and udder contents, from beef
carcasses by knife - trimming or steam -
vacuuming prior to washing and chilling
(Kochevar et al. 1997a ; Bacon et al. 2000 ).
Furthermore, FSIS has changed the meat and
poultry inspection regulations to require: (i)
establishment of sanitation standard operat-
ing procedures (SSOP); (ii) operation under
the hazard analysis critical control point
(HACCP) system; (iii) microbial testing of