What should the critical control points be in shell egg plants?

While shell egg plants do not fall in the scope of the Egg Products Inspection Regulation, an important question is still posed for egg producers: what should the critical control points (CCPs) be in shell egg plants?

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Courtesy of Altra Motion
Courtesy of Altra Motion
The egg washer is an important processing step when considering the assignment of CCPs (Courtesy of Altra Motion)

While HACCP (Hazard Analysis Critical Control Points) plans were required to be implemented in meat plants in 1996, egg plants are just recently following suit. Under the Egg Products Inspection Regulations final rule, the federal register is announcing that federally inspected egg products plants should develop and implement HACCP plans and Sanitation Standard Operating Procedures (SSOPs) to prevent shipment of adulterated product.

While shell egg plants do not fall in the scope, an important question is still posed for egg producers: what should the critical control points (CCPs) be in shell egg plants?

Dr. Kenneth Anderson, Extension Poultry Specialist at NC State, has devoted many research hours to study this question. “Production environment, egg temperature (initially and throughout processing and storage), and wash water pH and temperature play key roles in reducing microbial growth in shell eggs and should be key in developing a HACCP plan for shell egg facilities.” noted Anderson in Designing a Hazard Analysis and Critical Control Point (HACCP) Plan for Shell Eggs.

Water temperature and pH

The first CCP recommended is at the processing wash step. This is done by controlling Salmonella growth in eggs indirectly through wash water temperature and pH. Because wash water recirculates with replacement water at approximately four-hour intervals, temperature and pH change throughout the production shift. If eggs have cracks, bacteria is easily introduced. Anderson explains that maintaining a pH above 10.0 and temperatures of 90F or higher (or at least 20F warmer than the highest egg temperature) prevents microbial growth in the water. The temperature of the eggs being washed will vary depending on whether the eggs are conveyed directly from the layer house, how long they have been held in the house after being laid or if they brough in by truck from other farms for grading and packing.

The wash step removes potentially existing microorganisms from the eggshell surface that could move through the shell pores.  If the wash water is cool, the contraction of the air cell inside the eggs can pull those microorganisms through the pores to contaminate the inside of the egg.

The second CCP recommended is at the egg rewash step. Eggs detected as dirty after the initial wash step are sent to a rewash line. Repeatedly sending eggs through warm wash water could cause the internal egg temperature to increase, explained Anderson. Therefore, measuring the temperature of the rewash water could be beneficial in controlling microbial growth, especially if Salmonella is present. While a temperature for rewash water was not recommended, cooler temperatures are ideal.

The Egg Products Inspection Regulations in the federal register states that wash water must be changed every four hours to maintain sanitary conditions, be maintained at a temperature of 90F or higher (or at least 20F warmer than the highest egg temperature) and have a continuous overflow (9 CFR 590.515). It does not mention maintaining wash water pH or rewash water temperature, as Anderson does in his work.

Ambient air temperatures

The third CCP Anderson recommends is temperature in the processing cooler, where eggs are held before transport. A temperature of 45F or less was recommended and is a regulatory requirement (9 CFR 590.50) to prevent pathogen growth if present.

The final CCP recommended is temperature during transport. Eggs could be loaded onto trucks for distribution immediately after processing depending on the number of orders. Therefore, truck temperatures fall under the same 45F or less regulatory requirement as processing coolers.

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