FSIS plans to exclude vaccine strains from salmonella performance categorization
The Food Safety and Inspection Service (FSIS) of the USDA has announced that live vaccine strains of Salmonella administered to flocks will be excluded from calculations used to determine the status of plants under the Raw Poultry Performance Standards. FSIS Salmonella performance standards are assessed on broiler carcasses, turkey carcasses, comminuted chicken, comminuted turkey, and chicken parts (81 FR 7285).
FSIS examined Salmonella detection and serotype data from flocks vaccinated with a modified live Salmonella vaccine at pre- and post-intervention points in participating slaughter establishments. These data indicate that vaccine strains can occasionally be found in raw poultry products even when the vaccine is used as directed on the label. FSIS’ current policy of counting such strains as a positive result in performance categorization may discourage the use of vaccination as a tool to control Salmonella. To remove barriers to the use of these important pre-harvest interventions, FSIS intends to exclude current commercial vaccine subtypes confirmed in FSIS raw poultry samples from the calculation used to categorize establishments under the raw poultry Salmonella performance standards. This change will begin with categorizations calculated on or after April 1, 2024.Modified live Salmonella vaccines are used to reduce Salmonella colonization in poultry. These vaccine strains are not foodborne pathogens, making them a valuable pre-harvest tool for controlling wild-type Salmonella. FSIS can identify vaccine strains isolated from raw poultry products through the use of whole genome sequencing.
Live Salmonella vaccines approved for use in the US are all based on Salmonella typhimurium strains. Live Salmonella vaccines containing the attenuated Salmonella enteritidis strain, which are widely used with great success in many countries, including Europe, are not approved for use in the US.
