Operations at poultry processing plants owned by Wayne Farms and Sanderson Farms in Laurel, Miss., were put on hold after the Mississippi state health department advised that E. coli bacteria had been found in the city's water supply.

The state issued the warning on May 9, advising that city water utility customers boil all water before drinking it. The advisory was expected to last at least two days. Laurel has more than 23,258 water customers.

A Wayne Farms spokesperson said on May 13 operations had resumed after the state lifted its advisory on May 12. According to reports, the Sanderson Farms plant was looking to resume operations on May 13.

The state has deemed the water supply safe for all but six homes in Laurel.

City officials did not know the cause of the E. coli contamination.