Efficacy of combination chemicals as sanitizers of Salmonella-inoculated broiler hatching eggshells

Sanitization of broiler hatching eggs provides an opportunity to reduce the eggshell bacterial load entering hatchery incubators, which can be subsequently carried with the chicks to the grow-out farm and ultimately into the processing plant. Two experiments evaluated combination chemicals containing ammonium chlorides (NH4 Cl), biguanide (C2 H7 N5 R; BG), bronopol (C3 H6 BrNO4; BP), quaternary ammonium (NR4), or hydrogen peroxide (H2 O2) for efficacy in eliminating inoculated Salmonella from the shell of broiler hatching eggs. These chemicals were compared with no treatment, water sprayed (to account for spray rinsing of eggshells independent of sanitization), and to 1.4% H2 O2, a demonstrated effective hatching egg sanitizer for Salmonella. All 4 combination chemicals tested (2NH4 Cl+H2 O2, 2NR4+BP+BG, 4NR4, and 4NR4+BG) significantly reduced the recovery of Salmonella (80% to 100%) in comparison to the water-sprayed controls (a 9% to 20% reduction following water spray). In the second experiment, the chemical 4NR4+BG (containing 4 quaternary ammoniums and a biguanide) at 200 mg/L was as effective as H2 O2 at 1.4% in sanitizing hatching eggs for both Salmonella strains when the inoculum levels were 1 × 104 (0% positive) or 1 × 106 cfu/eggshell (3% positive). Following hatchability and chick quality trials for 4NR4+BG, this chemical should be considered for evaluation in commercial hatchery operations for the reduction of Salmonella on the shells of hatching eggs.