Giant Food Inc. announced yesterday that net income for the second quarter that ended Aug. 13 declined slightly despite an increase in sales for the period.

The Landover-based food chain said net income for the 12-week period was $8.2 million (56 cents a share), compared with $8.9 million (60 cents) in the comparable 1982 quarter. Sales increased 5.3 percent, from $419 million to $441.3 million.

Earnings before taxes were also lower compared with a year ago; from $15.7 million to $15 million.

A spokesman attributed the slight increase in sales and the dip in net income to seasonal trends. Sales should increase during the next 12 weeks, which contain several holiday periods, the spokesman added.

Despite the slight decline in net income for the quarter, Giant's earnings continued to be just under two cents on each sales dollar, still above the industry average of around one percent. Giant's net income as a percent of sales for the latest 12-week period was 1.86 percent, compared with 2.14 percent a year ago.

For the 24 weeks ended Aug. 13, Giant had net income of $17 million ($1.16) on sales of $886.1 million, compared with a net of $16.6 million ($1.11) and sales of $830.9 million.

Giant said sales increases of 5.3 percent and 6.6 percent for the second quarter and 24 weeks, respectively, are in excess of an estimated 2.6 percent inflation rate for food purchased in the Washington area during the same periods.