Albertson's Inc. cites its reduction in operating expenses as a chief reason for a 41-percent increase in third-quarter earnings from last year.

Sales for the 13 weeks ending Oct. 27 were $1.67 billion, an increase of 13.6 percent over the $1.47 billion for the same period in 1987. Net earnings for the quarter increased 40.8 percent from $27.1 million to $38.1 million.The company enjoyed sales of $4.88 billion in the first three quarters, up 12.3 percent from $4.35 billion in the first nine months of 1987. Earnings reached $110.7 million, an increase of 30 percent from the $85.1 million for the first 39 weeks of 1987.

"We are very pleased with the results for the third quarter and the first nine months of 1988," said Warren McCain, chief executive officer. "The company continues its commitment to reducing operating expenses . . . We project that 1988 will be our 19th consecutive year of increased sales and earnings."

During the quarter, four stores opened for a total of 22 new outlets during the first nine months of 1988. The company expects to add up to 15 stores in the final quarter.