Purpose: This study was conducted to validate a commercial baking process for hamburger buns to control Salmonella spp. contamination and to determine the appropriateness of using non-pathogenic surrogates (Enterococcus faecium or Saccharomyces cerevisiae) for in-plant baking validation studies.
Methods: Flour was inoculated separately with three stationary phase Salmonella serotypes (Typhimurium, Newport or Senftenberg), Enterococcus faecium ATCC 8459, or Saccharomyces cerevisiae (baker’s yeast). Dough was formed, proofed and baked to mimic commercial bun manufacturing conditions. Target microbial populations were enumerated using selective and injury-recovery media in re-dried inoculated flour, pre- and post-proof dough, after defined baking times (9, 11, and 13 min) at a ~218°C oven temperature, and after a 30 min ambient-air chill period following 13 min of baking.
Results: A ≥ 6-log CFU/g reduction for all baking times for all target bacteria was observed. E. faecium demonstrated greater thermal resistance compared to Salmonella spp., making it a suitable surrogate for commercial baking process validation studies, while S. cerevisiae demonstrated lower heat resistance than Salmonella spp. and E. faecium during initial baking trials and was deemed an inappropriate surrogate.
Significance: The experimental protocol developed and the Salmonella spp. reductions reported will assist the baking industry in conducting future process validations with additional product types and will assist bakers in complying with FSMA regulations.