A study was conducted to
examine the effects of cool water washing on the microbial quality of
shell eggs. Six dual tank wash water temperature schemes were examined
for their ability to reduce naturally occurring aerobic bacteria and
inoculated Salmonella Enteritidis (SE). The wash water schemes
were: T1= 48.9oC; T2 = 48.9oC, 23.9oC;
T3 = 48.9oC, 15.6oC; T4 = 23.9oC; T5
= 15.6oC; and T6 = 23.9oC, 15.6oC.
All wash water tanks were maintained from 10.5-11.5 pH throughout the
study. Eggs were exposed to the wash water temperature schemes in a
pilot egg washer with recirculating wash water tanks. The total amount
of time eggs were exposed to the wash water combinations was 60 s. Following
washing, all eggs were sprayed with a 48.9oC, 200 ppm chlorine
rinse solution. Eggs were stored and sampled for 9 wks. External aerobic
populations were lowest for T1 (typical U.S. wash water configuration),
followed by T2 and T3. Aerobic surface contamination was greatest in
T5 eggs. All treatments reduced SE levels in a similar manner as detected
by shell and membrane emulsion and egg contents pools after enrichment.
Commercial application of cool water shell egg processing will be investigated
to determine the potential of this technology to enhance the safety
and quality of shell eggs.