To make sure the fair's 150 or so food vendors comply, inspectors will be out every day checking on the oils in use.
Jason Smalley is making the rounds on the eve of open day, giving warnings.
"Facilities are not allowed to use products containing artificial trans fats," said Smalley, the lead inspector.
Smalley is checking oil deliveries too with most labels indicating zero trans fats.
"It has to be less than .5 grams of artificial trans fat per serving," Smalley said.
Anything more could result in a shut down, although vendors are given a chance to switch oils.
But the smell of grease in the air, the corn dogs, the fries, that's the allure of a state fair. Some fairgoers aren't so sure trans fat-free oil matters.
"It's kind of silly," said Michele Baird on a trip to the fair. "I mean, you come here exactly to eat junk food. If you're going to have a deep-fried Twinkie, what does it matter what grease it's fried in?"
Some vendors try to offer healthy alternatives, like grilled gator.
But the numbers from Wright during the Alameda County Fair suggest the demand isn't always there.
"We probably sold 12 veggie burgers compared to 2,000, 3,000 hamburgers," Wright said.