Best Products Co. Inc., the Richmond catalogue showroom retailer, reported a sharp loss in third-quarter earnings yesterday. Best said it suffered a loss of $5.3 million, compared with a profit of $2.8 million (10 cents a share) in the third quarter last year. Sales increased slightly, however, from $474.8 million to $480.5 million.

Sales also were higher for the first nine months this year, rising from $1.2 billion a year ago to $1.3 billion. Again, profits were off, resulting in a loss of $8.7 million, compared with a profit of $1.7 million (7 cents) in the first nine months of last year.

Baltimore Gas and Electric Co. said net income for the first 10 months of the fiscal year was $221 million ($5.08), compared with $186.8 million ($4.31) for the comparable period a year ago. Net income for the 12 months ended Oct. 31 was $250 million ($5.73), compared with $179.6 million ($4.74) a year earlier.

Telecom Plus International Inc. reported net income of $4.8 million (21 cents) for the quarter ended Sept. 30, compared with a loss of $6.3 million (28 cents) for the comparable quarter a year earlier. Sales for the quarter increased 63 percent, from $24.3 million to $39.5 million.

Scott Seaboard Corp., owner of the Scott's chain of home and garden centers, suffered a loss of $13,000 (a penny) in the third quarter, which ended Oct. 27, compared with a profit of $65,000 (4 cents) in last year's third quarter. Sales were higher at $9 million in the recent quarter, compared with $8.6 million in the comparable period last year. Net income for the first nine months was $453,000 (25 cents), compared with $1.2 million (68 cents) in the comparable period last year.

Eastmet Corp. recorded a loss totaling $7.9 million ($1.58) on sales of $52.2 million in the third quarter, which ended Sept. 30, compared with a loss of $3.5 million (71 cents) and sales of $47.6 million in the comparable period last year.

For the nine-month period ended Sept. 30, the Cockeysville, Md., steel processing and manufacturing company reported a loss of $5 million ($1.01) on sales of $191.5 million, compared with a loss of $8.6 million ($1.75) and revenue of $131.1 million last year.