ARS | Publication request: NATIONAL EGG TEMPERATURE SURVEY: 3. TRANSPORT

Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2004
Publication Date: August 11, 2004
Citation: Anderson, K.E., Patterson, P.H., Koelkebeck, K.W., Darre, M.J., Carey, J.B., Ahn, D.U., Ernst, R.A., Kuney, D.R., Jones, D.R. 2004. National egg temperature survey: 3. transport. Poultry Science. 83(suppl.):156.

Technical Abstract: The Egg Safety Action Plan released in 1999 by the President's Council on Food Safety, raised many questions concerning egg temperature patterns used in the risk assessment model. Therefore, a national study was initiated to determine the temperature sequence of eggs from oviposition through distribution. Researchers composed of Extension Specialists and USDA-ARS, in CA, CT, GA, IA, IL, NC, TX, and PA gathered data on internal and external egg temperatures from commercial egg production, processing, and distribution operations. The main effects being evaluated were: geographic region, season, and type of operation. Egg temperature data were recorded for specific lots of eggs during transport to point of resale or distribution to retailers. In order to standardize comparisons between loads specific segregation was made between long and short hauls within the samples collected and the impact of geographic region is eliminated since long haul loads moved from region to region. The experimental design was a mixed model with random effects for season, and a fixed effect for duration of the transport period (long or short haul). It was also found that processors have a tendency to use the refrigerated transport trailers as short-term storage in both the winter and summer seasons. Therefore, this summary of data obtained from transport trucks also examines the impact of refrigerated trailers being used as short-term storage. Egg temperature was not significantly reduced during the load phase (short term storage). The decrease in egg temperature was smaller (P<0.0001) during short hauls 0.6ºC than during long hauls 7.8ºC. There was a significant season by haul interaction (P < 0.01) for internal egg temperatures. In the winter, egg temperatures during long and short deliveries were very similar at 10.5 and 13.4ºC compared to summer when egg temperatures were 11.0 and 22.7ºC, respectively. Mean egg temperatures declined during transport similarly during the summer and winter. The temperature differential between ambient and egg temperatures was only 0.4 ºC from the start to the end of the delivery. The use of refrigerated trailers being used as short-term storage should be critically evaluated since egg temperatures are not appreciably reduced during this time period. These data suggest that the season of year affects the temperature of eggs during transport. Eggs are appreciably cooled on the truck, only during the delivery phase, which was contrary to the original supposition that egg temperatures would remain static during the refrigerated transport. This should be a component in future assessments of egg safety.