Meat Decontamination 45
unwashed animals (Biss and Hathaway 1995 ;
Mies et al. 2004 ). For instance, single or
double pre - slaughter washing with water or
chemicals (e.g., lactic acid and chlorine)
increased the percentage of positive
Salmonella samples on hides of live cattle
from 35 – 60% pre - treatment to 40 – 72% after
treatment (Mies et al. 2004 ). However, other
studies have demonstrated promising results
against pathogen contamination. For instance,
power - hosing of pigs or cattle for 1 – 3
minutes, upon arrival at the abattoir, with
depends on climate, type of animal, and
availability of facilities (Sofos and Smith
1998 ; Kain et al. 2001 ). Indeed, although
animal washing may remove almost all
visible contamination from animal surfaces,
it may have limited effectiveness ( < 1 log 10
CFU/cm^2 ) in reducing microorganisms (Biss
and Hathaway 1995 ; Kannan et al. 2007 ). A
concern is that it may release microorgan-
isms from feces and redistribute microbial
contamination, resulting in washed animals
carrying higher microbial loads than
Arrival of animals
and holding
Stunning
Exsaguination
(sticking)
Hide opening
Head removal
Evisceration
Carcass-splitting
Chemical
dehairing
Trim rail
Final washing
Chilling
Carcass fabrication
Cuts and trimmings
Knife-trimming
Steam-vacuuming
Water (cold/hot)-
washing
Chemical rinsing
Spray-chilling
Steam
pasteurization
Hot water-spraying
Chemical rinsing
Post-chilling
chemical or other
interventions
Animal
washing
Knife-trimming
Steam-vacuuming
Chemical
dehairing
Knife-trimming
Steam-vacuuming
Water (cold/hot)-
washing
Chemical rinsing
Spray-chilling
Steam
pasteurization
Hot water-spraying
Chemical rinsing
Post-chilling
chemical or other
interventions
Animal
washing
Pre-evisceration
Post-evisceration
Knife-trimming
Steam-vacuuming
Figure 3.1. Stages of beef - slaughtering dressing process and points where various physical or chemical decon-
tamination interventions may be applied. Based on Bell (1997) ; Gill and Bryant (1997b) ; and Edwards and Fung
(2006).