Hundreds of thousands of shoppers in the US state have started stocking up household essentials after up to 70,000 supermarket employees launched an indefinite strike.
Staff at 859 stores walked out on Saturday after union negotiations over pay and medical and pension benefits broke down, sparking the first supermarket strike in southern California in 25 years.
Talks between the United Food and Commercial Workers International Union and three supermarket chains - Vons, Ralphs and Albertsons - collapsed, sending workers onto the picket lines.
While hundreds of stores closed when staff walked out, most reopened at the weekend with emergency staff manning them, while opening hours have been shortened and some departments shuttered.
"It is likely going to be several weeks before we sit down again," said Vons spokeswoman, Sandra Calderon in Los Angeles.
Staff were picketing the stores on Monday in a bid to force customers to shop elsewhere until the labour action had been settled, causing many stores to be all but deserted by customers.
Two of the three affected chains, Albertsons and Ralphs, locked out their striking employees.
"It is likely going to be several weeks before we sit down again"
The union says the grocery companies want to cut health care benefits by 50%.
In addition, the firms are seeking a temporary wage freeze and the right to hire new employees for less money.
But the grocers said their proposal on health care was not as bad as the union had portrayed it.
"In view of the explosive growth in health care costs, the companies are asking employees to share in a very small portion of their health care benefits - $5 a week for the employee's coverage and $10 to $15 a week to cover the entire family," they said in a statement.
The union represents about 70,000 market workers in southern California and beyond. With about 900 stores in southern California, the three companies represent 60% of the area's grocery store market.