US food group Ralcorp Holdings has seen its quarterly earnings soar by more than 54% thanks to earnings from the Post cereals business it acquired two years ago.

The company, which makes a range of store-branded foods, booked first-quarter net earnings of US$65.5m for the three months to 31 December, up 54.5% on the year.

Ralcorp, which also owns a 17% stake in mountain resort operator Vail Resorts, said EBITDA from its food divisions more than doubled form $66.2m a year ago to $136.1m.

The group pointed to "incremental" EBITDA from the Post business, which it bought from Kraft Foods in November 2007.

Ralcorp also saw profits from its snacks portfolio and its sauces and spreads division rise during the quarter, although frozen bakery earnings dipped despite higher sales.

Ralcorp's group sales rose from $650.7m a year ago to $968.2m.

Reported diluted earnings per share fell from $1.61 a yea earlier to $1.15 due to lower gains on forward sale contracts from Vail and integration costs linked to the Post acquisition.

Stripping out these items, diluted earnings per share rose 16% to $0.80.