Reducing microbial contamination on meat and poultry products is a tricky business.
While it is crucial for operators to combat contamination that might emanate from an animal’s hide and gastrointestinal tract or the environment, an effective program typically requires a variety of measures.
“We cannot rely on one single intervention or step to control foodborne pathogens,” says Sara Gragg, associate professor of food science in the Department of Animal Sciences and Industry at Kansas State University, in Manhattan. “Applying interventions and/or management practices that reduce these foodborne pathogens at multiple points in the system is a multiple-hurdle approach that creates an additive reduction in pathogen load.”
A pre-harvest intervention that lessens pathogens in the animal or environment will result in a lower pathogen load entering the abattoir on the hides or in the gastrointestinal tract, which allows post-harvest interventions, such as carcass washes, to be more effective, she says.
While steam vacuums, hand trimming, pre-evisceration antimicrobials sprays, hot water carcass washes, and carcass spraying with lactic acid or peroxyacetic acid (PPA) are important for controlling bacteria and are part of the slaughter process, the antimicrobial interventions “will not work unless plants follow strict sanitary dressing practices,” says Robert Delmore, a professor in the Center for Meat Safety and Quality and the Department of Animal Sciences at Colorado State University, in Fort Collins.
Pathogen control during slaughter begins with hygienic dressing procedures during sticking, removal of the hide, and evisceration, and operators should use clean and sanitized equipment and utensils throughout slaughter, Gragg says. “Care should be taken to minimize pathogen transfer from hides to the carcasses, which may include ensuring proper air flow away from the carcass to prevent contamination through the air during hide removal,” she says
Some facilities employ a hide spray or wash, which may include an antimicrobial, to remove contamination from the hide prior to hide removal, Gragg says.
Live-animal intervention steps, meanwhile, can include cleaning of hides, she says, but notes that animal welfare must be a priority when implementing an intervention. “Maintaining clean conditions for live animals at the slaughter facility is important for pathogen control,” she says. This includes removing fecal material, proper drainage, and maintaining clean common areas, such as lairage and holding pens, chutes, and alleyways.
While the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) requires operators to remove visible contamination, such as feces or ingesta, with a knife or steam vacuum, carcasses often just undergo one or more washes with water or a chemical intervention, she says.
Appropriate measures can include a hot water carcass wash of about 80 degrees Celsius (176 degrees Fahrenheit), “which is one of the most effective interventions for reducing carcass contamination,” and the use of hypobromous acid, peracetic acid, and organic acids such as lactic acid, Gragg says.
Maintaining correct application parameters involving pressure, concentration, and temperature, along with the proper nozzle configuration, also is critical for effective pathogen reduction, Delmore says. “In addition to the physical parameters of these interventions, the sanitary dressing practices must be adhered to by employees,” he says. “Even the most efficacious treatment will fail if not properly applied.”
Other operational issues include the need to move toward water reduction and sustainability without sacrificing food safety, while also maintaining intervention concentrations that are at or below regulatory limits, Gragg says.
“A combination of multiple interventions is still the best approach to controlling the carcass microbiological condition,” Delmore says. “A holistic approach where a plant focuses on training and well-designed observational monitoring and data analysis with actions for continuous improvement can minimize significant bacterial events.”