'No contract, no coffee': Starbucks workers strike in 40 cities

The union Starbucks Workers United began an indefinite strike Thursday in at least 40 cities and 65 locations of the coffee chain, coinciding with 'Red Cup Day,' one of the most important sales days for the company.

More than 1,000 baristas joined the strike after the collapse of the negotiations to reach a collective contract with the company. The mobilization, which could extend over the next few days, threatens to affect holiday season sales, a key period for Starbucks' financial results.

The protest comes at a delicate time for the company, which is seeking to regain momentum in the U.S. market under the leadership of its new CEO, Brian Niccol. Although Starbucks claims that previous strikes impacted less than one percent of its stores, the scale of the current walkout could pose a greater challenge.

The union is demanding better working conditions, wage increases and a resolution to unfair labor practice complaints against the company. According to Workers United, negotiations have not resumed since late last year, when the last attempts at dialogue failed.

Both sides blame each other for the lack of progress. Starbucks maintains that it remains open to negotiation and recalls that its offer includes compensation and benefits that exceed $30 per hour on average.

For their part, union representatives insist that they will not return to work without a fair agreement. "If Starbucks continues to refuse to negotiate and end anti-union practices, their business will grind to a halt," warned Michelle Eisen, a Workers United spokeswoman and former barista with 15 years of experience. "No contract, no coffee," she added to CNBC in a statement Monday.