(Reuters) - Kroger Co (>> Kroger Co), the biggest U.S. supermarket operator by store count, reported a better-than-expected quarterly profit as the company cut costs and its comparable sales grew.

Shares of the company, which owns the Ralphs, Smith's and Food 4 Less grocery chains, rose as much as 5.8 percent to a record high of $40.33 on Thursday.

Kroger has acquired smaller rivals Harris Teeter Supermarkets Inc and Roundy's Inc (>> Roundy's Inc) to grow its business and expand into newer markets.

The company has also entered organic foods business with its "Simple Truth" brand to attract a growing number of shoppers looking for healthier options.

"Kroger's merchandising execution is very strong in natural and organic products," Pivotal Research Group analyst Ajay Jain said.

The Cincinnati, Ohio-based company raised its full-year earnings forecast to $2.02-$2.04 per share from $1.92-$1.98.

The company's third-quarter sales, excluding fuel, rose 5.4 percent at stores open for more than a year without expansion or relocation, beating analysts' average estimate of 4.5 percent rise, according to research firm Consensus Metrix.

Lower retail fuel prices helped Kroger's total sales grow 0.4 percent to $25.08 billion. Analysts on average expected $25.22 billion, according to Thomson Reuters I/B/E/S.

Excluding fuel, total sales rose 5.5 percent.

The net income attributable to Kroger rose 18.2 percent to $428 million, or 43 cents per share, beating the average analyst estimate of 39 cents per share, according to Thomson Reuters I/B/E/S.

Up to Wednesday's close, the stock had risen about 19 percent this year.

(Reporting by Subrat Patnaik in Bengaluru; Editing by Kirti Pandey and Anil D'Silva)

By Subrat Patnaik

Stocks treated in this article : Kroger Co, Roundy's Inc