The impact of egg handling and storage temperature on shell eggs stored for 27 weeks: Egg quality

Eggs are an important trade commodity around the world. However, how eggs are handled/processed and stored differ by country. In the United States, under federal and state regulations, eggs are washed and stored at refrigerated temperatures. These practices can be an obstacle if the eggs are destined for export markets. The focus of this study was to assess the impact of egg handling practices and storage temperature on egg quality during a 27-week storage period. Conventional commercial white shell eggs were obtained and handled under four treatments: 1) unwashed (U) 2) washed (W; USDA-Agricultural Marketing Service (AMS) guidelines), 3) washed and oiled (O; food-grade mineral oil; AMS guidelines), and 4) 21 days refrigerated storage (AMS guidelines) then washed (21 W). All egg handling occurred at a commercial facility. The eggs were then transported to the US National Poultry Research Center in Athens, GA. Three cases of eggs from each egg handling treatment were stored in either refrigeration (R; 4 °C) or room temperature (A; 22 °C). To determine egg weight loss throughout the study, 30 eggs were randomly selected from each treatment/replicate combination and grouped according to storage temperature. These eggs were then weighed each week to determine egg weight loss throughout the 27 weeks of storage. At Weeks 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, 18, 22, and 27, ten eggs were randomly selected from each replicate of egg handling treatment and storage temperature combinations and assessed for various physical egg quality parameters. The greatest decreases in egg weight were observed in eggs at 22 °C: A-U, A-W, and A-21 W (P < 0.0001). A-O eggs had comparable egg weight loss to eggs stored at 4 °C. Storage temperature had a profound impact on Haugh units. After one week of storage at 22 °C (P < 0.0001), A-W, A-21 W, and A-U eggs had dropped to USDA-AMS Grade B. A-O eggs were able to maintain Grade A through 4 weeks of storage (P < 0.0001). Haugh unit measurements for 22 °C stored eggs were only possible until 8 weeks of storage. R-O and R-U eggs were able to maintain Grade A Haugh unit scores (P < 0.05) through 27 weeks of 4 °C storage. R-W and R-21 W eggs retained Grade A Haugh unit scores through 18 weeks (P < 0.05). This study shows the importance of storage temperature on preserving egg quality over extended storage.