In a first for the U.S., California on Saturday put a bill on the books that'll ban the administration of antibiotics to livestock unless there's a specific health issue with which the medication would improve. In just over two year's time, California ranchers will no longer have the option to use antibiotics simply to fatten up their livestock.

California Gov. Jerry Brown signed the bill into law in Sacramento on Saturday. The bill, which will take effect on Jan. 1, 2018, will offer strict deterrents to prohibit the use of "medically important antimicrobial drugs," to livestock without a prescription from a licensed veterinarian or a veterinary feed directive.

The bill will also "prohibit the administration of a medically important antimicrobial drug to livestock solely for purposes of promoting weight gain or improving feed efficiency," the law stated. 

Violating the bill would draw a penalty of up $250 per day for the first violation and would double if there was a second infraction. Along with the fines, violators will have to attend classes on the "Judicious use of medically important antimicrobial drugs" approved by the state's secretary.

"The violator shall successfully complete the program and provide proof to the secretary within 90 days from the occurrence of the violation," states the law.Underscoring the need to leave antibiotics outside of the U.S. food supply chain wherever possible, the governor indicated that he signed the bill to address an "urgent public health problem."

"The science is clear that the overuse of antibiotics in livestock has contributed to the spread of antibiotic resistance and the undermining of decades of life-saving advances in medicine," said California's Brown.

It's a landmark move, but it's important to point out the antibiotics in question are distinct from the growth hormones many farms like to use to hurry along the maturation of animal to get them fatter for market and to get them to the tables faster.

Still, many companies, such as Panera and Chipotle, have begun working with their suppliers to end the use of antibiotics and that's a good thing, notes Consumer Report's Michael Hansen, a senior scientist at the Consumers Union policy division.

"No state yet has been able to pass a bill that is stronger than the one in California, and the fact that California is an important ag[ricultural] state, that makes this an important action," Hansen said.