For some products, though, the spikes in sodium content are alarming: Hardee's French fries, for instance, contain three times as much sodium as they did in 2005. Wal-Mart's cream cheese nearly doubled in sodium. Jimmy Dean's Regular Premium Pork Sausage, salty enough in 2005 with 280 milligrams of sodium per serving, has 60 percent more in 2008. Some 109 products increased by 5 percent or more and 29 products increased by 30 percent or more. On the other hand, sodium in 114 products declined by 5 percent or more and 18 products declined by 30 percent or more. The rest remained about the same.

"The food industry is knowingly overusing a chemical that can cause crippling disease or early death," CSPI executive director Michael F. Jacobson said. "Despite 30 years of unkept promises from food companies, nothing has changed. The average sodium content remains dangerously high. The next Administration can't sit by incuriously as chain restaurants and food manufacturers recklessly turn Americans' brains and hearts into ticking time bombs."

Health officials see lower-sodium diets as a major public health goal, because current levels promote high blood pressure, which, in turn increases the risk of heart attacks and strokes. In 2004, the director of the National Heart, Lung, and Blood Institutes, and two colleagues estimated that cutting sodium in foods by 50 percent would save about 150,000 lives annually. The American Medical Association, American College of Cardiology, and many other health groups have urged that industry gradually achieve that 50-percent reduction over a ten-year period.

While some companies maintain that current levels are necessary for purposes of taste or preservation, CSPI found large brand-to-brand differences in numerous categories of foods. That indicates that some companies could easily lower sodium levels and still have perfectly marketable products. For instance: Arby's French fries have three times as much sodium as McDonald's fries. Bumblebee white albacore canned tuna has 70 percent more sodium than Crown Prince. And Kraft's Classic Caesar salad dressing has almost twice as much sodium as Annie's Natural version.

Products that have less sodium in 2008 than they did in 2005 include Contadina Roma Style Tomato Paste, Pepperidge Farm's Hot Dog and Hamburger Buns, and Hungry Man Boneless Fried Chicken Frozen Dinner.

The sodium in processed foods comes mostly from salt, but also from monosodium glutamate (MSG), baking soda, sodium nitrite, and a myriad of other additives. About 10 percent of the sodium that people consume occurs naturally in foods.

In 2005, CSPI petitioned the U.S. Food and Drug Administration to change the “generally recognized as safe” status that salt enjoys in order to limit the amounts in various categories of food. New York City, Los Angeles, Wisconsin, Boston, and others have all endorsed that measure. FDA held a hearing on CSPI's petition in September 2007, but has done nothing since.

“The sixth edition of the Dietary Guidelines for Americans was published in 2005, the base year of our survey,” Jacobson said. "And for the sixth straight time the government urged that sodium consumption be cut. Apparently, most food manufacturers just aren't listening."

In contrast to the FDA’s decades-long inactivity on salt, over the several years the British government has waged a major campaign to persuade companies to lower sodium levels and consumers to choose lower-sodium products. The government's goal is to lower sodium consumption by one-third over five years. Consumption is already down by 10 percent, which Graham MacGregor, Professor of Cardiovascular Medicine at St. George's University of London, estimates is saving 6,000 lives there annually.