Validation of a Simulated Commercial English Muffin Baking Process to control Salmonella Contamination

A validation study was conducted to investigate the effect of the English muffin baking process to control Salmonella contamination and to study the thermal inactivation kinetic parameters (D- and z-values) of Salmonella in English muffin dough. The unbleached bread flour was inoculated with 3 serovar Salmonella cocktail (Salmonella serovars viz., Newport, Typhimurium, and Senftenberg), and dried back to its pre-inoculated water activity levels with 7.46±0.12 log CFU/g of Salmonella concentration. The Salmonella inoculated flour was used to prepare English muffin batter and baked at 204.4°C (400°F) for 18 minutes and allowed to cool at ambient air for 15 minutes. The English muffins reached 99 ± 0°C (211.96±0.37°F) as their maximum mean internal temperature during baking. The pH and aw of English muffin dough were 5.01±0.01 and 0.947±0.003, respectively. At the end of the 18 min baking period, the Salmonella inoculated English muffins recorded a more than 5 log CFU/g reduction on the injury-recovery media. The D-values of 3 serovar cocktail of Salmonella at 55, 58.5, and 62°C were 42.0±5.68, 15.6±0.73, and 3.0±0.32 min, respectively; and the z-value was 6.2±0.59°C. The water activity (aw) of the English muffin crumb (0.947±0.003 to 0.9557±0.001) remained statistically unchanged during baking, whereas the aw of the muffin crust decreased significantly (0.947±0.003 to 0.918±0.002) by the end of 18 min of baking. This study validates and documents first scientific evidence that baking English muffins at 204.4°C (400°F) for 18 minutes act as an effective kill step by controlling Salmonella population by >5 log CFU/g.