CHICAGO (Reuters) - U.S. cases of two deadly types of foodborne pathogens have fallen sharply since 2008, but rates of other key types of foodborne bugs have increased, according to the latest report on nine pathogens tracked by health officials.

"The picture is mixed," said Dr. Patricia Griffin of the U.S. Centers for Disease Control and Prevention's division of foodborne diseases, adding, "Most of it is not good news."

Despite making progress in certain areas, U.S. health officials have made no progress in curbing overall rates of Salmonella and Campylobacter - two pathogens that cause the highest number of illnesses in people.

To see improvement on those two, "we're going to have to see some widespread changes in the meat or poultry industry, so that the reservoirs for these organisms are less contaminated," Griffin said, commenting on the report issued on Thursday.

Dr. David Goldman of U.S. Department of Agriculture's Food Safety and Inspection Service said the agency has proposed new pathogen reduction performance standards for two problem pathogens in poultry - Salmonella and Campylobacter.

The new rules affect chicken parts and "comminuted" chicken and turkey - poultry that has been mechanically deboned and chopped up into smaller parts. "We estimate within two years, these standards should prevent an estimated 50,0000 cases of Salmonella and Campylobacter annually," Goldman said on a teleconference.

Goldman also said his agency has issued a final rule requiring the clear labeling of mechanically tenderized beef products, as well as detailed cooking instructions, an action he said USDA "hopes will prevent hundreds E. coli illnesses every year."

The CDC's report is based on data collected from agency's FoodNet surveillance system, which tracks nine pathogens in 10 U.S. states. In the report, cases of laboratory-confirmed Shiga toxin-producing E. coli 0157, which can sometimes lead to kidney failure, fell by 32 percent, compared with 2006-2008 and 19 percent when compared with the most recent three years.

These infections are often linked to consumption of undercooked ground beef and raw leafy vegetables. Salmonella Typhimurium, which has been linked to poultry, beef, and other foods, fell by 27 percent compared with 2006-2008, continuing a downward trend begun in the mid-1980s. But the incidence of Campylobacter, Vibrio and two less common types of Salmonella - Javiana and Infantis - rose during the same period. When all Salmonella serotypes are combined, there was no change in 2014.

"The data released today provide encouragement, but still tell us the road is long," said Dr. Kathleen Gensheimer of the U.S. Food and Drug Administration's Coordinated Outbreak Response and Evaluation Team.

Gensheimer said FDA is on schedule to issue final rules late this summer for the Food Safety Modernization Act, a sweeping package of food safety reforms. Among the areas to be covered are produce safety, preventive controls for food produced in facilities, and the safety of imported food, she said.

Overall in 2014, FoodNet logged just over 19,000 infections, about 4,400 hospitalizations, and 71 deaths from the nine foodborne germs it tracks. Salmonella and Campylobacter were by far the most common– accounting for about 14,000 of the 19,000 infections reported.

The real number of infections is likely much larger, however, because many people with foodborne infections are never tested. Griffin estimates that for every person with a lab-confirmed case of Salmonella, for example, there are about 29 other people who also had the infection but were not tested.

(Reporting by Julie Steenhuysen; Editing by Frances Kerry)