US: FSIS and testing for Salmonella in lymph nodes
Posted: May 31st, 2012 - 12:02pm
FSIS testing for Salmonella in beef lymph nodes would have enormous implications for the beef industry. At a minimum, it raises questions about what actions the agency would take when results are positive. The biggest unknown is whether some strains of Salmonella would be considered adulterants? Another unknown is the incidence of Salmonella in beef lymph nodes. Is it much higher than E. coli O157:H7 and other STECs? Also, what can be done about contamination in the lymphatic system?
It appears that FSIS and the beef industry may soon be dealing with the issue. One of the points addressed in the recent Office of the Inspector General (OIG) report on N-60 testing that received very little attention is the fact that within the next few years, FSIS intends to examine external lymph nodes in beef cattle for the presence of Salmonella.
Traditionally, most of the focus on Salmonella has been directed to the poultry industry. However, recent outbreaks and recalls in the US and Canada have involved beef products. In some cases, the recalls resulted from the presence of multi-drug resistant strains ofSalmonella. These strains are resistant to a range of antimicrobials, including first-choice antibiotics. Presumably, the resistance results from the use of antimicrobials both in humans and animal husbandry. Multi-drug resistance to “critically important antimicrobials” is compounding the food safety problems associated with Salmonella.
The issue of what action should be taken when Salmonella is found in lymph nodes is an open question. Although Salmonella is not classified as an adulterant in raw beef products, it can lead to a recall when implicated in a public health event. In 2009, 825,000 pounds of ground beef was recalled because of suspected Salmonella contamination.
The possible contamination of beef lymph nodes with Salmonella raises some difficult challenges for the industry. First, it isn’t possible to remove all lymph nodes from beef cuts and trim, so what can be done when contamination is found? In addition, the interventions currently used during beef slaughter operations are designed to address contamination associated with hide removal and evisceration. They do not address potential contamination from infected lymph nodes.
Fortunately, FSIS testing for Salmonella in beef lymph nodes is not likely to begin for several years. Hopefully, in the interim, FSIS will clearly establish which (if any) Salmonella strains will be considered as adulterants. The beef industry should to take this time to conduct research to establish the incidence of Salmonella on beef carcasses and in lymph nodes and identify the prevalent strains. The industry should also consider preharvest interventions and beef slaughter treatments specifically designed to address Salmonella on carcasses and in the lymphatic system.