Chapter 6
Recent Advances in Pre- and Postslaughter Intervention Strategies for Control of Meat Contamination
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J. D. Stopforth and J. N. Sofos Department of Animal Sciences, Colorado State University, 1171 Campus Delivery, Fort Collins, C O 80523-1171
The main approaches employed in controlling microbial contamination in meat products include application of procedures to: (i) minimize sources and levels of microorganisms reaching the slaughter facility; (ii) minimize access or transfer of microorganisms from the animal's exterior and the slaughter environment to the meat; (iii) reduce contamination that has gained access to the meat; (iv) inactivate microorganisms on the meat and meat products; and, (v) inhibit or retard growth of contamination that has gained access to meat and meat products and has not been inactivated. In general, control of microbial contamination on meat products may be accomplished through pre- and post-slaughter intervention strategies. Pre-slaughter or field control of pathogen prevalence in live animals prior to arrival at slaughterhouses may be achieved via good management practices such as market classification of animals, clean housing, feed and water, pest control, and transport/lairage control or via interventions such as diet modifications, feeding of pathogen displacement agents (prebiotics, probiotics, and competitive exclusion), feed additives, antibiotic treatments, vaccine administration, and bacteriophage therapy. Control of
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© 2006 American Chemical Society
In Advances in Microbial Food Safety; Juneja, V., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2006.
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67 pathogen contamination on the animal carcass during slaughter and dressing may be achieved through employment of animal cleaning and carcass decontamination technologies, while control at the post-slaughter stage is attained by application of antimicrobial, thermal and non-thermal physical interventions, fermentation, drying, refrigeration or freezing, and antimicrobial packaging. The preservation of meat products is, thus, effectively achieved through combinations of antimicrobial interventions in multiple-hurdle systems. The objective is to maximize the effect of individual antimicrobial interventions in order to achieve an additive or synergistic action that controls contamination more efficiently than the individual treatments applied singly.
It is well established that foodborne pathogenic bacteria are a major cause of illness and death among humans, accounting for substantial economic losses and suffering. It is estimated that foodborne microbial hazards result in approximately 76 million cases of illness, 325,000 hospitalizations, and 5,000 deaths annually in the United States alone (7). The United States National Health Objectives for 2010 aim at reducing the incidence of illness caused mainly by four foodborne pathogens, namely Campylobacter, Salmonella, Escherichia coli 0157.Ή7 and Listeria monocytogenes, to 12.3, 6.8, 1.0, and 0.25 cases per 100,000 populations, respectively (2). Efforts by the food industry during the last decade have translated into declining trends of infection with cases of L. monocytogenes almost reaching the "Health Objectives" initiative of no more than 2.5 cases per million people, and a 42% decrease in E. coli 0157:H7 cases (i). The production of meat and meat products involves the slaughter of livestock and subsequent processing of raw meat. Muscle tissues of healthy live animals are generally considered sterile and, thus, processing should yield safe meat products provided that the meat is handled safely and processes are applied correctly (4). This, however, is not always the case and pathogens have the ability to evade antimicrobial processes and to contaminate our food supply. Meat is contaminated through two major sources, namely the live animal and the processing environment which is also contaminated by the animal and vice versa (5). During slaughter, bacteria from the animal hide or gastrointestinal tract may cross-contaminate the underlying and exposed carcass surfaces. Furthermore, cross-contamination may occur from processing tools, equipment, structural components of the facility, human contact and carcass-to-carcass contact ((5). Although, it can be assumed that some level of microbial contamination of
In Advances in Microbial Food Safety; Juneja, V., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2006.
68 animal carcasses will occur during slaughtering and dressing (7), its extent is dependent on the conditions under which animals are reared, slaughtered, and processed (
