1. Place the following foodborne causative agents in order from least to most virulent according to their infectious dose?
Escherichia coli (EHEC), ID50 = 10
Hepatitis A, ID50 = 10-100
Norovirus, ID50 = 1-10
Staphylococcus aureus, ID50 = 100,000-8,000,000
Giardia lamblia, ID50 = 1
Listeria monocytogenes, ID50 = 1,000
2. Provide four reasons why S. aureus (ID50 = 100,000-8,000,000) has such a large ID50 range. (Hint: think about factors that can affect a microbe's overall virulence)