A professional who conducts experiments to detect presence of harmful or pathogenic bacteria in water, food supply, or general environment of community and to control or eliminate sources of possible pollution or contagion. Responsibilities include:

• Makes periodic laboratory counts of bacteria in water supply.
• Analyzes samples of sewage for harmful micro-organisms and for rate of sludge purification by aerobic bacteria.
• Examines milk, shellfish, and other food items for micro-organisms constituting menace to public health.
• Cooperates with hospitals and clinical laboratories in identifying micro-organisms taken from diseased persons to determine presence of bacteria causing contagious or epidemic diseases.
• May inoculate members of community against contagious diseases.