Location: ESQRUTitle: Equivalency of peracetic acid to chlorine as a shell egg surface sanitizer.
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2020
Publication Date: 7/20/2020
Citation: Jones, D.R., Garcia, J.S., Gast, R.K., Ward, G. 2020. Equivalency of peracetic acid to chlorine as a shell egg surface sanitizer. Poultry Science. 99(1):259.
Interpretive Summary: None
Technical Abstract: In the US, all shell eggs processed under the USDA Agricultural Marketing Service voluntary grading standards must receive a sanitizing rinse after leaving the washing process of 100 – 200 ppm chlorine or its equivalent. A study was conducted to determine the concentration of peracetic acid (PAA) which would be equivalent to 100 – 200 ppm chlorine under the required washing conditions for shell eggs. Three isolates of Salmonella spp. (Enteritidis, Braenderup, and Typhimurium), as well as Enterobacter cloacae (indicator organism frequently detected in shell egg processing environment), were utilized as inocula. Sanitizing treatments were: negative control; deionized water; 100 and 200 ppm chlorine; and 50 – 500 ppm peracetic acid (7 concentrations). Over three replications, up to 30 intact eggs were assessed for each inoculum and sanitizing treatment combination. Organism enumeration data was analyzed by ANOVA with a general linear model and least square means separation. Prevalence of viable, but not culturable, organisms was analyzed by Chi-square. Considering all microbial numbers, 100 and 200 ppm chlorine had 2.6 and 2.3 log cfu/ml remaining on shell surface; 50 and 100 ppm peracetic acid had 1.9 and 1.0 log cfu/ml remaining, respectively, compared to untreated control average of 3.8 log cfu/ml (P < 0.001). Salmonella Typhimurium was least resistant to shell sanitizer treatments. Peracetic acid concentrations > 250 ppm did not produce significant reductions in microbial populations as PAA concentration increased. Culturing for the prevalence of viable and injured organisms, 400 – 500 ppm PAA resulted in fewer eggs (P < 0.0001) being positive for Salmonella spp. Enterobacter cloacae was culturable via enrichment from 99.4% of inoculated eggs, regardless of sanitizer treatment. The results of this study indicate that 50 -100 ppm PAA is equivalent to 100 – 200 ppm chlorine in reducing egg surface microorganisms. The use 400 – 500 ppm PAA resulted in a lower incidence of viable, but not culturable, Salmonella spp. on the shell surface. Enterobacter cloacae resulted in almost 100% viable, but not culturable, organism recovery for all sanitizing treatments and should be considered as an indicator organism when studying processing facility sanitation procedures.