Effect of Kosher Processing on Shiga Toxin-Producing Escherichia coli (STEC) and Salmonella on Surfaces of Fresh Beef and Its Quality

Introduction: The main reason that people buy kosher products is for the impression of improved food quality and safety. However, both STEC and Salmonella may contaminate surfaces of fresh beef during slaughtering and many antimicrobial interventions cannot be applied due to kosher restrictions.  Although the salting process to remove blood from the meat has antibacterial effects, the impact of the kosher beef salting process on foodborne pathogens has not been determined.

Purpose: To evaluate antimicrobial efficacy of kosher salt and quality of kosher beef during storage at refrigeration temperature.

Methods: Forty-two pieces of fresh beef were inoculated with cocktail mixtures of top seven STEC and Salmonella to approximately10⁴ to 10⁵ CFU/cm². Inoculated fresh beef was soaked with tap water for 45 min, salted (Kosher certified) for 45 min, and rinsed with water three times for 2 min each rinse. Enumeration for each kosher processing step was conducted to determine efficacy of salt in reducing target organisms after processing and after storage for 2 d at 2 to 4^oC. The salt residue and lipid oxidation also were determined after processing and after storage for 7 d at 2 to 4^oC.    

Results: Water soaked alone or water soaked and chilled did not reduce the population of STEC and Salmonella on surfaces of fresh beef. Salt treatment alone reduced seven STEC strains and Salmonella ranging from 0.8 to 1.4 log cycle with additional 0.2 to 0.6 log cycle reduction after chilling for 2 d. The salt residue from kosher beef was 14 times higher than non-kosher beef. The amount of malondialdehyde from kosher beef increased three times compared to non-kosher beef during 7 d storage.

Significance: Kosher processing significantly reduced foodborne pathogens.  However, the kosher process increased salt levels which could cause off-flavors from salt-accelerated lipid oxidation.

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