Misleading labels on food products may be leading to people consuming higher amounts of trans fat than they're aware of, the New York Department of Health and Mental Hygiene says.

Department researchers analyzing more than 4,300 popular packaged foods found partially hydrogenated oils, a significant source of trans fat, in 9 percent of them, but 84 percent of those had labels listing their trans fat level as "0 grams."

Amounts from minuscule traces up to 0.5 grams per serving were found; the Food and Drug Administration has ruled foods with trans fat levels of less than 0.5 grams per serving can be labeled as having "0 grams."

"This labeling is cause for concern because consumers, seeing the 0 g trans fat on the nutrition facts label, are probably unaware that they are consuming trans fat," the researchers reported in the Center for Disease Control and Prevention journal Preventing Chronic Disease.

Created by adding hydrogen to oil to make it solid, trans fat has been linked to a number of health problems, most particularly elevated cholesterol levels.

Previous studies have shown that even as little as a couple of grams of trans fat consumed daily can increase levels of so-called bad cholesterol while diminishing good cholesterols, raising risks of heat disease, diabetes and stroke.

While consumption has decreased in the U.S. since trans fat's health risks were first recognized decades ago, it still is found in much of the foods Americans consume, the study researchers say.

"The sense is that trans fat is mostly gone from foods. And what we see is there's still a lot being used in packaged foods," says one of the study's authors, Christine Curtis, assistant commissioner in the New York City health department. "We think consumers are unknowingly consuming artificial trans fat and the recommendation is to consume as little as possible."

Some categories of food were found to be particularly likely to contain trans fats, the researchers found, including half of the potato chip category and a third of cookies.

The FDA is mulling a policy change that would declare partially hydrogenated oils unsafe, which would require their complete removal from all food products.

Consumer can still protect themselves, nutritional experts and public health officials say: If a food product label claims "0 g trans fat," a careful look at the list of ingredients may still reveal the term "partially hydrogenated" or the letters "PHO" for partially hydrogenated oils.