THE U.S. DEPARTMENT of Agriculture, in an effort to monitor better the amount of added water in hams, has proposed regulations that would abolish the current limits and replace them with mandatory minimum levels of protein, as part of the government standard for a variety of cured pork products.

Most of the hams on today's market contain added water. The industry says consumers prefer them that way because the extra moisture makes them juicier and more tender.

For the USDA's Food Safety and Inspection Service, which regulates the addition of water and other added substances to cured pork products, keeping the amount of water down to the legal limit has been a continual headache.

Two years ago, USDA's inspector general criticized FSIS for using out-of-date laboratory methods for checking added water--methods that allow some processors routinely to pump in more water than permitted in the regulations. "As a result," the inspector general said, "adulterated products are entering consumer channels, and meat processing plants are able to maximize profits at the expense of the consumer because of outdated inspection controls."

Thus USDA officials proposed the regulation, reasoning that protein content can be more precisely measured than added water. The method, the proponents explain, would indirectly measure moisture: The more water in a product, the more diluted the protein content.

Currently, the regulations work like this:

* Cooked canned hams "with natural juices" contain a maximum of 8 percent added substances, none of them "natural." Usually 4 to 5 percent of this maximum is water and the remainder is other additives, such as sodium nitrite, salt, sweeteners and phosphate. Right now, hams labeled "with natural juices" can only be sold in cans. Under the proposed regulation, the phrase "with natural juices" would be retained, and such products could also be marketed in plastic wrapping.

* Cooked hams and other pork cuts labeled "water added" may absorb up to 10 percent added water, over and above the additives used for curing. This means there is 5 to 6 percent more water in these products than in canned hams. Current rules prohibit these products from being sold in cans, but the proposal would permit a canned version of "Ham, Water Added."

* Hams with more than 10 percent added water must be labeled with the percentage of added water as part of the product. The proposal would require the label "Ham and Water Product," along with a mandatory statement of the percentage of added water. Under current rules, hams are the only pork cuts permitted to absorb more than 10 percent water. But under the proposed rules, shoulder butts and picnics, loins, and chopped, pressed and spiced ham could also contain an unlimited amount of water--as long as that amount was stated on the label, accompanied by the "water product" terminology.

Most of the hams with more than 10 percent water are sold to institutions, restaurants and delicatessens, where the label is not likely to be on display. However, Dr. George Wilson, vice-president for scientific affairs at the American Meat Institute, predicts the meat industry will object to the term, "Ham and Water Product." "It doesn't make it a very attractive item," he says.

USDA officials were careful to write the proposal without requiring across-the-board, and therefore costly, changes in the majority of ham labels now on the market. Consequently, they have retained the "natural juices" phrase for canned hams, though they readily admit there's nothing "natural" about those juices. "That gets debated in here as well as out of here," says Merlin Nelson, deputy administrator of technical services in FSIS' Meat and Poultry Inspection Program.

Consumer advocate Thomas Smith, of Public Voice for Food and Health Policy, calls the labeling "outrageous," complaining, "it doesn't clarify anything." Smith said the market would work better if the percentage of added water were required on all ham labels.

Wilson of AMI says that if the proposal becomes law, consumers may see an increase in hams "with natural juices" on the market. These hams, plastic-wrapped, he predicts, could serve as a "middle ground" between hams with no added moisture, which many consumers find too dry, and hams with 10 percent or more added water.

According to Richard Epley, a meat extension specialist at the University of Minnesota in Minneapolis, the extra water in hams tends to produce a "halo" effect--hams that are more juicy "may seem more tender and flavorful even if they are not."

Wary consumers will wonder whether the extra water in ham means they are paying pork prices for water. In its proposal, USDA said there is no information on the price differences of cured pork products containing various amounts of water. "A whole myriad of factors enters into the retail price," says Wilson, "and added water is only one of them." Wilson contends, however, that the competition "keeps the price of water-added hams in line."

If you want to comment on the USDA proposal, the deadline is March 10. Address your letters to: Regulations Office, FSIS Hearing Clerk, Room 2637 South Building, U.S. Department of Agriculture, Washington, D.C. 20250.