US food companies Sara Lee and ConAgra Foods have issued statements denying any improprieties in their relationship with US Foodservice, the Ahold subsidiary that is at the centre of an accounting scandal.

The denials came after media reports last week claimed that officials were investigating allegations that US Foodservice had colluded with some of its suppliers to inflate income.

"ConAgra Foods' sales to Royal Ahold reflect ordinary and appropriate business practices in the foodservice industry, and ConAgra Foods is not aware of any financial impact to ConAgra Foods because of the Royal Ahold investigation," the US food company said in a statement.

Sara Lee said it had not been contacted by US regulators regarding the accounting irregularities at US Foodservice and said it was unaware of any questions regarding its relationship with the Ahold unit.

Sara Lee said that it had reviewed all of its records associated with the company’s food service distributors and confirmed that its conduct and accounting was appropriate and accurate.

Meanwhile, US meat processor Tyson Foods has said it has been contacted by federal authorities investigating US Foodservice, reported the Wall Street Journal. The company declined to give further details but said it would cooperate fully with the inquiries.