Final answer:
Regulating Salmonella spp. would have the greatest effect in reducing the likelihood of illness in humans.
Step-by-step explanation:
Bacteria Species and Their Effects on Contamination of Agricultural Products
In order to determine which bacteria species would have the greatest effect in reducing the likelihood of illness in humans, we need to consider the prevalence and virulence of each species. Unfortunately, the given information does not specify the four bacteria species shown in the graph.
However, based on the information provided, pathogenic strains of Escherichia coli, Salmonella spp., and Staphylococcus aureus are commonly associated with foodborne illnesses and are of significant concern.
Among these, Salmonella spp. is considered highly prevalent and is responsible for a large number of foodborne illnesses each year. This bacterium can survive and multiply in various food products, including poultry, eggs, and raw fruits and vegetables. Therefore, regulating Salmonella spp. would likely have the greatest effect in reducing the likelihood of illness in humans.