Location: Poultry Microbiological Safety Research
Title: Comparison between Rinse and Crush-and-Rub Sampling for Aerobic Bacteria Recovery from Hatching Eggs after Sanitization Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: October 15, 2010
Publication Date: January 24, 2011
Citation: Spickler, J.L., Buhr, R.J., Cox Jr, N.A., Bourassa, D.V., Rigsby, L.L. 2011. Comparison between Rinse and Crush-and-Rub Sampling for Aerobic Bacteria Recovery from Hatching Eggs after Sanitization. Meeting Abstract. 90(7):1609-1615. Technical Abstract: This study compared surface and deep eggshell aerobic bacteria recovered by rinse and crush-and-rub sampling methods for commercial hatching eggs after treatments with sanitizers. Eggs were arranged into 5 treatments consisting of three sanitizers, Water, and No-treatment. Sanitizers were Hydrogen Peroxide (H2O2), Phenol, and a compound chemical (quaternary ammoniums+biquanide, Q4B). Eggs were sprayed according to treatment and allowed to dry for 1 h before sampling. To collect samples for the eggshell rinse, each egg was massaged in a plastic bag with 20 mL saline. Eggshells were then aseptically cracked, the contents discarded, and individually crushed into 50 mL centrifuge tubes also containing 20 mL of saline. Aerobic bacteria were enumerated on Petrifilm™ after 48 h incubation at 37'C. Aerobic bacteria recovered (log10cfu/mL) from the rinse were highest and similar for No-treatment (4.0a) and Water (3.7a), lower for Phenol (3.2b) and H2O2 (3.1b), and lowest for Q4B (2.4c). Crush-and-rub means were similar for No-treatment (2.5a) and Water (2.3a), lower for Phenol (1.6b), intermediate for H2O2 (1.2b,c), and lowest for Q4B (0.9c). The overall correlation between the rinse and crush-and-rub sampling methods for aerobic bacteria counts was r = 0.71. The correlation within each treatment revealed the following r values: No-treatment 0.55, Water 0.72, H2O2 0.67, Phenol 0.73, and Q4B 0.38. A second experiment was designed to further examine the lower aerobic bacterial levels recovered by crush-and-rub than recovered in the initial eggshell rinse sample. Eggs were either rinsed and then crush-and-rubbed or only crush-and-rubbed without a prior rinse. Results confirmed a significant decrease (1.5 log10cfu/mL) in bacteria levels between the initial rinse (4.4a) and subsequent crush-and rub (2.9b) for the same eggshell. For the crush-and-rub eggs with no previous rinsing, the bacteria recovery level (3.9a) was not significantly different from rinse levels. Therefore, either rinse or crush-and-rub sample methods can be used to recover eggshell aerobic bacteria.