Heat Treatment for Disinfecting Egg Transport Tools

Abstract

HighlightsDisinfecting shell egg transport tools before their reuse is an integral biosecurity step.Avian influenza viruses are heat labile and it can be disinfected with high temperatures.Lab tests proved that egg transport flats and pallets can be heated to 54°C to 60°C in 7 to 9 h.Egg farm tests identified main factors for consideration in designing heat treatment system.Abstract.Disinfecting shell egg transport tools such as egg flats and pallets before their reuse has become an integral biosecurity step after the 2015 highly pathogenic avian influenza (HPAI) outbreaks in the United States. Lab-scale tests and field verification were conducted to investigate dynamic temperature changes and distributions inside stacks of egg pallet and flat at a surrounding air temperature of 54°C to 60°C (130ºF to 140ºF) in this study. The heat treatment tests were conducted in the lab first, and then verified in a newly built heat treatment room [12 m (L) × 4 m (W) × 3 m (H)] on a commercial laying hen farm in Iowa, the largest egg production state in the United States. Iowa lost more than 30 million hens during 2015 outbreak of HPAI. The lab tests proved that air circulation with fans could accelerate the heat exchange between air and stacks; blowing air from top and bottom at the same time plus arranging a 2.5 cm (1 in.) space between stacks could reduce the heat treatment time for the target temperature zone (i.e., 54ºC to 60ºC) from 26 to 60 h (without air circulation) to 7 to 9 h. For commercial egg farm tests, heat treatment results show that the room air and egg pallet stacks temperature reached the target zone (54ºC to 60ºC) in 30 min and 4 h after starting the heater, respectively. However, the temperature of egg flat stacks failed to reach the targeted zone after 8 h heating, because it had larger volume and heat transfer resistance as compared to egg pallet stacks. Further experiments such as extending heating period and installing mixing fans to accelerate heat exchange between the room air and the stacks are suggested for improving heat treatment system design on commercial farms. Keywords: Avian influenza, Disinfection, Egg flat and pallet, Egg production.