California Code, Health and Safety Code - HSC § 101150

For the purpose of protecting the community and the public health, the local health department of a city or county shall have available the services of a public health laboratory for the examination of specimens from suspected cases of infectious and environmental diseases, that may include, but need not be limited to, the examination of specimens from milk, milk products, waters, food products, vectors, and the environment. The public health laboratory shall also provide the analyses required to assist in community disease surveillance and to meet the responsibilities and support the programs of the local health department.