SOUTH PORTLAND – Barbara Winthrop used to regard her health insurance coverage as a fundamental entitlement, a benefit she could not imagine an employer failing to provide.

But since she became the owner of a small business, she cannot afford to provide insurance for her 15 workers.

Winthrop, who owns Barbara’s Kitchen & Cafe, said the explosive rise in the cost of health insurance is keeping her from acting on her belief – that everyone should have health insurance.

Her idealism runs smack into economic reality every time she gets quotes on premiums and deductibles.

She’s not alone. Small businesses are having a tough time providing benefits than large, profitable corporations – and in Maine, nearly half of all workers are employed by companies with fewer than 50 workers.

Earlier this year, a survey showed the number of Maine small businesses offering health insurance to employees is dropping, and is likely to keep dropping because of rising premiums.

The report, compiled by the Maine Center for Economic Policy and Consumers for Affordable Health Care, shows that workers are paying more of their health insurance costs, and that one in five employers thinks rising costs have led some workers to forego coverage.

But 81 percent of those surveyed also said health benefits were essential to attracting and retaining workers.

“Health insurance has become the biggest issue for small businesses,” said Joseph Ditre, executive director of Consumers for Affordable Health Care.

“They’re losing quality workers to bigger employers and medium-sized employers in Maine.”

A variety of factors is driving insurance costs higher.

They include the use of expensive, modern medical tests and treatments, an aging population and the double-digit percentage increases in the costs of prescription drugs, according to Ditre.

The state now has approximately 161,000 people without coverage, Ditre said. The U.S. Census Bureau places the national figure at 42.6 million.

Winthrop said she does not believe the nation will solve the health insurance crisis until it touches more people.

“I think somebody needs to tackle these insurance companies and get them to respond to the needs of the people out there.”

Most of Winthrop’s workers are in their 20s or early 30s and healthy, but several said they worry about not having health insurance.

“Insurance is obviously a big load off your mind,” said Bob Dube, 32, who works as a cook.

“I’m single and take care of myself at this point, but there have been things that have happened to me since I worked here that I could have used insurance for.”