Handbook of Meat Processing

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).