WASHINGTON - The food industry is jeopardizing U.S. public health by withholding information from food safety investigators or pressuring regulators to withdraw or alter policy designed to protect consumers, said a survey of government scientists and inspectors.

A study released on Monday by the Union of Concerned Scientists found one-in-four of those surveyed have seen corporate interests forcing their agency to withdraw or modify a policy or action designed to protect consumers during the past year.

Pressure to overhaul the food safety system has grown following several high-profile outbreaks involving lettuce, peppers, eggs, peanuts, spinach and most recently eggs that have sickened thousands and shaken the public's confidence in the safety of the food supply.

The 44-question survey, conducted earlier this year, also found more than 38 percent of those respondents said public health has been hurt by businesses influencing food safety policy at the U.S. Food and Drug Administration and the U.S. Agriculture Department.

"Upper level management does not adequately support field inspectors and the actions they take to protect the food supply," said Dean Wyatt, a USDA veterinarian who oversees federal slaughter house inspectors. "Not only is there lack of support, but there's outright obstruction, retaliation and abuse of power."

Despite the concerns, 67 percent of the respondents -- 72 percent at FDA and 65 percent at USDA -- said their agency is "moving in the right direction."

The survey was sent to 8,122 individuals working on food safety at the FDA and USDA. Just over 1,700 employees from all levels of the food safety system responded. USC said recipients were told their responses would be kept confidential and anonymous.

Foodborne illnesses sicken an estimated 76 million people in the United States each year and are fatal to 5,000, according to the U.S. Centers for Disease Control and Prevention.

The massive salmonella outbreak that sparked a recall of more than a half billion eggs from two Iowa plants in August could provide momentum for the Senate to act on its own food safety bill later this month.

The House passed food reform legislation in July 2009.