Iron and Iron Bacteria in Egg Processing Well Water
In 2009, Georgia commercial egg plants processed almost 12.5 million cases (360 eggs per case) of table eggs (USDA, 2010). A survey of water use in 73 U.S. commercial shell egg processing facilities in 2005 showed that 2 out of every 3 (66%) facilities used water supplied by on-site wells (Jones and Northcutt, 2005). The survey also showed that the average shell egg plant utilizes 1.5 gallons of water per case, which means Georgia egg processors use about 19 million gallons of water each year. In 2005, researchers from the University of Georgia’s Agricultural and Environmental Services Laboratories (AESL) reviewed 10 years (1993-2004) of drinking water test results from private wells in Georgia and found that 15% had iron levels above the EPA’s secondary drinking water standard of 0.3 ppm (Sonon et al., 2005). Also, according to the USDA, iron levels in egg processing plant water must not be higher than 2.0 ppm since egg white does not contain iron which aids in preventing microbial growth. Thus the introduction of iron to shell eggs could increase microbial spoilage (Zeidler, 2002).