Swab plant workers’ hands and test for bacterial indicators (such as E. coli, fecal coliform or total coliform) every 2 months without prior notice. When test results indicating fecal contamination, test for Hepatitis A virus (HAV) and Norovirus (NoV). If virus is detected, temporarily remove the person affected from positions requiring direct contact with food, verify the health condition of the person and repeat test to confirm the infection. If viral infection is confirmed, the plant worker shall not return to work until NoV and/or HAV infection is confirmed negative. Consider increase the number and frequency of test if virus is detected repetitively.