Food prices in the Washington area increased 7.6 per cent during the year ending Oct. 31, compared to a nationwide city average increase of 7.0 per cent, the Bureau of Labor Statistics reported yesterday.

The BLS noted, however, a decrease in local gorcery store prices of 0.5 per cent for the month of October compared to the previous month. Prices customarily decline at thii time of year, BLS analyst said, but the decline this year was somewhat less than expected.

A breakdown of the overall 7.6 per cent annual increase in local food prices since October, 1976, shows that grocery store prices went up only 7.0 per cent, while restaurant prices jumped 8.8 per cent.

Among grocery store items, cereal and bakery products rose 6.3 per cent, and meat, poultry and fish increased 7.4 per cent during the year. Dairy products declined 1.6 per cent, according to the BLS report.

While grocery store prices declined 0.5 per cent on the average during October, some specific items dropped more sharply. Meat, poultry and fish decreased 0.9 per cent, led by especially steep declines in pork prices, notably bacon and sausage, the BLS said.

In contrast to the general decline in grocery store prices during October, the BLS reported increases in September and August of 0.3 and 0.5 per cent, respectively.

These included especially big jumps in the price of fruits and vegetables and a whopping increase of 5.1 per cent in the cost of cereal and bakery goods in the month of September alone.

The BLS food price index, computed on a 1967 base of 100, now stands at 202.5 for the Washington area. This means a basket of groceries that cost $10 in 1967 now costs slightly more than $20.

Food industry representatives have cited numerous factors they say cause higher prices here. These include increased labor costs, distance from centers of production of meat, fruits and vegetables and local demand for high quality and service.