Whole Foods, the grocery chain owned by Amazon.com Inc., is cutting health benefits for its part-time workers in a move that could leave about 1,900 of them without medical coverage.

Starting next year, Whole Foods employees have to work at least 30 hours a week to qualify for company health insurance benefits, up from the 20 hours a week currently required.

The upscale grocer, which has about 95,000 workers, said it is making the change "to better meet the needs of our business and create a more equitable and efficient scheduling model," according to Business Insider, which first reported the benefits change. Whole Foods said it is helping workers explore full-time jobs at its stores or find other ways to get health coverage.

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The move was roundly condemned by labor advocates, some of whom said that health cuts essentially undo the higher minimum wage of $15 an hour that Amazon announced last year.

"Amazon's plan to cut health care for these part-time employees is one of Jeff Bezos' most brazen attacks on the quality of jobs at Whole Foods and the communities they support," Mark Perrone, president of the United Food and Commercial Workers International Union, said in a statement.

Online shopping giant Amazon, whose biggest individual shareholder is billionaire founder Jeff Bezos, bought Whole Foods two years ago for nearly $14 billion, cutting prices on some items and adding its smile logo in its aisles as well as expanding delivery services for customers.