WASHINGTON (AP) _ The Agriculture Department has a new cookbook this fall for school cafeterias which includes some new recipes, labor-saving tips and a little pizazz for the pinto beans.

In all, there are 161 recipes in the revised publication, ''Quantity Recipes for Type A School Lunches,'' the first new model since 1971.

School meals are served to 24 million children in 90,000 schools across the country.

Assistant Secretary John W. Bode says ''food service has changed dramatically'' since the previous recipes were issued 17 years ago. The new ones, he says, feature more optional ingredients and seasonings to reflect regional food preferences.

The recipes were developed over two years under a $320,000 contract, plus another year and $2 million to print and distribute 90,000 copies free to state agencies and regional offices. Development included surveys of state agencies, a taste panel and test schools.

Under the lunch program, USDA provides about $3.7 billion in cash grants and commodity donations to participating school districts.

The per-pupil costs of meals can vary greatly. USDA provides subsidies according to the family income of school children. Those subsidies range from about $1.60 per meal for meals provided free of charge to poverty-level homes to less than 27 cents per meal for children from affluent families.

According to the department's Food and Nutrition Service, the new ''recipe file'' includes variations of recipes where appropriate and ''makes good use of USDA-donated commodities to help keep down the cost of lunches.''

Some nutrition experts have criticized school menus for allowing too much fat, sugar and salt in the meals. One group, Public Voice for Food and Health Policy, recently said that while school meals have improved they still fall short of USDA's own dietary guidelines.

The agency's report said that ''to the extent practical and acceptable, moderation of added sugar, fat and salt'' was taken into consideration when the revised recipes were drafted.

''However, no arbitrary levels of any one ingredient was specified in the contract,'' the report said. '' The recipes were never intended to be therapeutic in nature.''

The report added, ''Certainly, added sugar, fat and salt was a major consideration, but they were also balanced with the many other constraints inherent in quantity food production systems and, in particular, to the uniqueness of school feeding programs and their regulated meal patterns.''

About half of the 161 recipes in the new file are ''popular revisions'' of ones in the old set.

''Schools continue to serve spaghetti, lasagna and oatmeal cookies,'' the report said. ''All recipes were restandardized. Improved preparation methods and ingredient choices were incorporated into the recipes, keeping in mind the need to work efficiently and still please student appetites.''

The contract specified that recipes not only be acceptable but accommodate regional and local needs and preferences. Where possible, alternative ingredients are allowed, such as the use of pinto or kidney beans in the chili con carne recipe.

''For example, cheddar cheese is a suggested garnish for the chili, and canned green chili peppers may be used (or not used) in cornbread and nacho cheese sauce,'' the report said. ''And because Mexican and Italian flavors rank so high in children's food preferences, master seasoning mix recipes have been included, which can be adjusted to accommodate local food preferences.''

A ''nutrients per serving'' table gives the values for 15 different nutrients on all recipes.

The agency said the recipes also ''eliminate as many preparation steps and pieces of cooking equipment as possible'' and lists ''labor-saving alternative ingredients such as dehydrated onions.''