Bactericidal Efficacy of Food Additive-Grade Calcium Hydroxide Against Salmonella Infantis on Eggshells.

The bactericidal efficacy of food additive-grade calcium hydroxide [FdCa(OH)2] was evaluated for inactivation of Salmonella Infantis and Salmonella Enteritidis in liquid and Salmonella Infantis on contaminated eggshells. The activity of FdCa(OH)2 was also compared with that of sodium hypochlorite (NaOCl) containing 150 ppm chlorine (150 ppm NaOCl). FdCa(OH)2 solutions (0.1% and 0.2%) in the presence or absence of organic materials (5% calf serum [CS]) at pH 12.6 were used to inactivate Salmonella Infantis and Salmonella Enteritidis in a reaction tube or on eggshells artificially contaminated with Salmonella Infantis. Both 0.1% and 0.2% FdCa(OH)2 were capable of inactivating Salmonella Infantis and Salmonella Enteritidis in liquid at >3 log10 colony-forming units (CFU)/ml within 3 and 1 min of contact time, respectively, even in the presence of 5% CS. Additionally, 0.1% and 0.2% FdCa(OH)2 reduced bacterial levels on contaminated eggshells to >3 log10 CFU/ml, within 3 and 1 min, respectively, in the presence of 5% CS. Without CS, 0.1% and 0.2% FdCa(OH)2 could reduce bacteria on eggshells to >3 log10 CFU/ml within 1 min and 30 sec, respectively. In contrast, 150 ppm NaOCl solution could not inactivate bacteria on eggshells down to >3 log10 CFU/ml within 3 min contact time, either with or without CS, and no bacterial reduction was observed in redistilled water. The findings of the present study indicate that FdCa(OH)2 solution has high efficacy against foodborne bacteria and may be a good candidate for enhancement of biosecurity at farms and egg processing plants.