Off the bus, Ms. Alvarez headed to a parking lot in Salinas where the United Farm Workers and the U.F.W. Foundation were handing out bags of food to hundreds of laborers, something they began doing weekly as the outbreak worsened. “A lot of them don’t get to have enough food on their tables,” Leydy Rangel, a spokeswoman for the foundation, said.

It was after 6 p.m. when Ms. Alvarez made it home. She threw her work clothes into a bag to avoid contaminating the house, took a shower and then began cooking dinner for her daughter, Diana Barreto, 22, who is among the masses of newly laid-off retail clerks.

[Read about why black and Latino Californians are suffering disproportionately from the virus.]

The two rent a room in a three-bedroom house they share with Ms. Alvarez’s sister, brother-in-law and their two children. Dinner on the stove, Ms. Alvarez set about preparing lunch for the next day. She almost always makes bean, potato or nopales cactus burritos, adding beef sparingly. The burritos are often tomorrow’s dinner, too, eaten in the field during her last afternoon break.

Ms. Alvarez does her best to keep enough beans and potatoes on hand to bulk up their meals as the month goes on. She and her daughter now spend more time searching markets, driving to food banks, rationing what’s in the fridge and worrying about tomorrow. “I have to keep an eye on the food we have so that it could last a few more days,” she said.

Ms. Alvarez came to California 30 years ago from Michoacán, Mexico, and found work in the strawberry fields. In the years since, she has moved from crop to crop, wherever working conditions were a little better. Her current job offers three days of paid sick leave, which is why she seizes every opportunity she can to use the hand sanitizers now being provided in the fields.

“I have to take care of myself more because we don’t know what might happen,” she said. “If I get sick, I will have to stop working, the food will run out and I won’t have money to pay the rent.”

[Read more about California’s undocumented essential workers.]

Although Ms. Alvarez’s job in the food chain is considered essential, she knows that because of her undocumented status she will not get the $1,200 in relief money being distributed to individuals by the federal government. (Gov. Gavin Newsom, however, has announced that undocumented workers will get up to $500 from the state.)