Chapter 5 - On-Farm Food Safety Programs

To date there is no single identified critical control point that will assure reductions of food-borne pathogens, but integration of multiple approaches, focused on known critical control points, has been partially effective.

Any program developed to reduce carcass contamination with food-borne pathogens must start with live production. Grow out conditions should be kept as clean as possible, and feed ingredients containing animal or fish by-products should be laboratory-certified free of Salmonella.

Clean breed flocks: There is evidence indicating that a major factor for ultimate success of ante-mortem intervention is the production and maintenance of food-borne pathogen free breeders flocks. This is difficult because of the necessity of feed restriction during growth and the stress associated with egg production but some of the interventions recommended for broiler growers will also hold for broiler breeder flocks.

Biosecurity: Wild birds, pets, rodents and people have all be implicated as fomites for transmission of Salmonella into broiler flocks. Because of the high animal density in modern broiler production, Salmonella is likely to amplify in an infected flock and persist through slaughter and processing.

Reduced light intensity: Reducing light intensity during the in-house feed withdrawal period reduces the incidence of litter pecking and has been shown to reduce crop contamination with both Salmonella and Campylobacter. With the potential for rupture and leakage during processing the crop is a potential critical control point.

Addition of organic acids to the drinking water: Feed withdrawal has been shown to change the environment of the crop, primarily by increasing pH. Changes in the crop environment have the potential for growth of food-borne pathogens. One way to reverse the increasing crop pH due to feed withdrawal is to re-acidify the crop. For example, 0.44% lactic acid in the drinking water has been shown to reduce Salmonella and Campylobacter contamination of chicken carcasses.

Use of chemical litter treatments: If litter acidity is reduced to about pH 5, conditions are unfavorable for Salmonella and other potential pathogens. To achieve this, chemical treatments can be added to the litter to lower the pH and reduce ammonia production. Such treatments must be cost effective and safe for farm workers. Several chemical additives have been used to decrease the pH of poultry litter. Examples include aluminum sulfate, ferrous sulfate, phosphoric acid, sodium bisulfate and acetic acid. For more information on litter treatments, refer to Chapter 14 - Litter Amendments.

Use of competitive exclusion products: The gastrointestinal tract of newly hatched chicks is essentially sterile and highly susceptible to colonization/ infection with pathogenic bacteria. One approach to prevent the colonization of pathogenic bacteria is to accelerate establishment of normal intestinal flora in chicks as early as possible, thus providing a source of competition for subsequent pathogens to which the host chick may be exposed. Competitive exclusion is the delivery of a suspension of healthy adult cecal microflora. The benefits of competitive exclusion treatment on reducing Salmonella and Campylobacter shedding and environmental contamination are now well documented.