Commercial breads containing wood pulp have been springing up all over the country. The manufacturers are taking advantage of the recent interest in the importance of fiber in the diet.

The best known of the breads and only one sold on a nationwide basis is ITT Continental Baking Co.'s Fresh Horizons.

The powdered wood pulp is listed as powdered cellulose on the list of ingredients.

A locally produced bread, which contains powdered wood pulp, made its appearance several months ago at High's, 7-11, Pantry Pride and A&P. It is called Schmidt's Blue Ribben High-Fiber Bread and is produced in Baltimore. The formula for the bread comes from Quality Bakers of America, which supplies it to various regional bakeries.

According to the director of Quality Bakers laboratory and technical research: "Sometimes the fiber in the bread comes from the soybean hulls; right now the fiber is out of wood."

It is listed on the Schmidt label as "natural fiber."

There are no scientific studies to show whether ingesting wood pulp in the large quantities in which it appears in these breads is safe.

Most physicians who recommended increasing fiber intake say it should be done by eating more fruits and vegetables and whole grain breads.

The Department of Agriculture panel that has been studying sodium Nitrate for three years will be getting four new panel members soon. One wanted to be a member when the panel first was formed but Agriculture officials vetoed his name because his opinions about the hazards of nitrits are far stronger than any of the other panel members.

Dr. William Lijinsky, director of the chemical careinogenisis program at the Frederick (Md.) Cancer Research Center, is expected to join the panel along with another critic of sodium nitrite, Dr. Michael Jacobson, co-director Center for Science in the Public [WORD ILLEGIBLE] . Jacobson has called bacon, which is preserved with sodium nitrite, one of the most dangerous foods at the supermarket.

Sodium nitrite is used to celer, flavor and preserve processed meats. The panel has been examining alternatives to nitrites, which combine with other substances called ashines to produce a potent carcinogen called nitresamines. Amines are found in tobacco, drugs and other foods, but the simple act of drying bacon causes the fermation of nitresamines.

The panel has made some suggestions for reducing the amount of nitrites used in processed meats: besides bacon, foods like ham, hot dogs, bacon, lunch meats. None of the panel's recommendations has been implemented.

Some people are calling for the total elimination of nitrites from the food supply, others feel nitrites have value in preventing the growth of the deadly bacteria, clostridium botulinum.

Carol Foreman, Assistant Secretary of Agriculture for food and nutrition services, said the panel has taken too long to make a decision on sodium nitrita. Its quarterly meetings will become monthly meetings. "The decision making process with regard to sodium nitrite has been inexcusably extended." Froeman said.

Efforts are being made at every level, from mothers of school-age children to the Congress of the United States, to get junk food out of the school vending machines and cafeterias.

Sen. Clifford Case (R-N.J.) has introduced legislation that would regulate the sale of "competitive or so-called junk foods." In 1972 amendments to the National School Lunch Act made such sales possible, Case said his amendment to eliminate the junk foods has been passed twice before by the Senate, but the vending machine portion was deleted in House-Senate conferences.

According to Case:" . . . It makes no sense at all to have junk foods, loaded with sugar and empty calories, competing with the nutritious food in the school lunch program.

A few local jurisdictions, including Washington, have been succesful in banning junk foods from vending machines on school property.

But this effort in the District has been only partially successful. Without nutrition education so that children understand why junk food is unhealthy for them, they go outside of school to buy it in stores in the neighborhoods or from what some of them are calling "junk trucks," which park a block or two away from the schools.

The bread which a New York City magazine and newspaper both consider among the best available in that city is now being sold in Washington.

Wagshal's on Massachusetts Avenue in Spring Valley has Speikermann's cruisy round bread for $1.25 a loaf. The loaf, produced by a Swiss bakery in Union City, N.J., weighs a little over a pound. It is made with unbleached white flour, water, yeast and salt and is baked in a stone oven and comes down fresh Tuesday through Saturday.

It will taste particularly good with the Pennsylvania Dutch color-free butter being sold at the Farm Woman's Market in Bethesda at the Berliner's stand. The pale yellow butter sells for $1.65 a pound.