Final answer:
Food handlers with the big five pathogens should be excluded from handling food to prevent the spread of foodborne illnesses, especially to vulnerable groups.
Step-by-step explanation:
Food handlers diagnosed with any of the big five pathogens - which include Norovirus, Hepatitis A, Salmonella Typhi, Shigella spp., and Escherichia coli (E. coli) O157:H7 - should be excluded from handling food. These pathogens can cause severe foodborne illnesses and are highly transmissible through food. Thus, when a food handler is diagnosed with one of these diseases, they should not work in a food service environment until they have been cleared by a medical professional. Certain groups, including pregnant women, young children, older adults, and those with weakened immune systems, are particularly vulnerable to foodborne illnesses.