Although unlikely, highly pathogenic avian influenza virus (HPAIV) could potentially contaminate the surface of table eggs laid soon after hens are infected. The risk to consumers is largely mitigated because hens cease laying soon after infection and eggs from infected flocks are immediately removed from the food supply. However, the risk is never zero. Sanitizing washes consisting of a basic wash (pH 11) followed by a 100-200 ppm chlorine rinse are applied to table eggs during the washing process in the U.S. Therefore, the objective of this study was to evaluate the effect of commercial washes on avian influenza virus (AIV) infectivity. To simulate commercial egg processing procedures, five commercial caustic eggs washes and a chlorine rinse were applied to artificially contaminated unwashed (nest run) fresh eggs from commercial table egg layers. Virus was quantified immediately after washing or after a 5-minute contact time; the virus titer was reduced an average of 5.3 log 10 50% egg infectious doses (EID 50 ) or 5.9 log 10 EID 50 , respectively. When caustic washes were tested without the chlorine rinse, the titer reduction varied among washes from 3.1 log 10 EID 50 to 5.3 log 10 EID 50 . The 100 ppm chlorine rinse alone reduced the titer by 2.7 or 3.4 log 10 EID 50 with no contact time or 5 min contact time respectively. The titer reduction from physical washing alone with viral transport medium was 2.0 log 10 EID 50 . These results support that the caustic washes with a chlorine rinse provide an additional layer of protection against HPAIV contamination from entering the food supply.
Cho et al. (Sun,) studied this question.