Temperature Sequence of Eggs from Oviposition through Distribution: Transportation Part 3

Authors: ANDERSON, K - N.C. STATE, N.C.; PATTERSON, P - PENN STATE UNIV, PA; KOELKEBECK, K - UNIV OF ILLINOIS, ILLINOI; DARRE, M - UNIV OF CONNECTICUT,CT; CAREY, J - TEXAS A&M, TX; AHN, R - IOWA STATE UNIV, IA; ERNST, R - UNIV OF CALIF, DAVIS, CA; KUNEY, D - UNIV OF CALIF, RIVERSIDE,; Jones, Deana

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2008
Publication Date: 6/1/2008
Citation: Anderson, K.E., Patterson, P.H., Koelkebeck, K.W., Darre, M.J., Carey, J.B., Ahn, R.A., Ernst, R.A., Kuney, D.R., Jones, D.R. 2008. Temperature Sequence of Eggs from Oviposition through Distribution: Transportation Part 3. Poultry Science.87(6):1195-1201.

Interpretive Summary: Understanding how shell egg temperature is affected by long and short term transportation is important in enhancing the microbial and physical quality of the eggs when they reach the consumers. Shell eggs are generally transported regionally to wholesale and retail customers. Maintaining both the physical and microbial quality of the eggs during this transport is important. Most foodborne pathogens associated with eggs can grow at temperatures greater than 7.2 C (45 F). Furthermore, the physical quality of the egg is better maintained at temperatures lower than 7.2 C. A national survey was conducted to determine egg temperature during both short and long-term transportation to retail. Egg temperature was monitored in the refrigerated trailers (REFERS). Egg temperature reduction was lower during short-term delivery compared to long-term delivery. There were instances when egg temperature increased in the winter during long-term delivery. The results of this study indicate a need for processors to re-consider the current practices utilized during refrigerated transport in order to maintain a reduced egg temperature. Altering the set temperature for the refrigeration systems on the trailers and routine maintenance to ensure cooling ability are also evident.

Technical Abstract: The Egg Safety Action Plan released in 1999 raised many questions concerning egg temperature (T) used in the risk assessment model. Therefore, a national study by researchers in CA, CT, GA, IA, IL, NC, PA, and TX was initiated to determine the internal and external T sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, processing, and distribution facilities. 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 determined that processors used refrigerated transport trucks (REFER) as short-term storage (STS) in both the winter and summer. Therefore, this summary of data obtained from REFERs also examines the impact of their use as STS. Egg T data were recorded for specific loads of eggs during transport to point of resale or distribution to retailers. In order to standardize data comparisons between loads, they were segregated between long and short hauls. The summer egg Ts were higher in the STS and during delivery. Egg T was not significantly reduced during the STS phase. Egg T decreases were less (P < 0.0001) during short delivery hauls 0.6°C than during long hauls 7.8°C. There was a significant season by delivery interaction (P < 0.05) for the change in the T differences between the egg and ambient T indicated as the cooling potential ('CP). This indicated that the ambient T during long winter deliveries had the potential to increase egg T. REFERs used as STS did not appreciably reduce internal egg T. These data suggest that the season of year affects the T 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 Ts would remain static during refrigerated transport. These data indicate that refrigerated transport should be a component in future assessments of egg safety.