WASHINGTON. The US packaged food giant Kraft Heinz has announced a $15.4 billion write down on some of its most iconic brands, reflecting a big change in what people like to eat.

In its fourth quarter earnings report, the company said Thursday that the write-down resulted in a net loss of $12.6 billion.

The company also announced it was subpoenaed late last year by the Securities and Exchange Commission over its procurement procedures.

All this and weak fourth quarter earnings figures caused the stock price to be down nearly 21 per cent after regular trading concluded.

Kraft Heinz said the write-down cut the balance sheet value of United States and Canadian operations and the famed Kraft and Oscar Mayer trademarks.

US news outlets said it appeared to stem from shifting consumer preferences in favour of fresh products over processed ones like Kraft Heinz classics such Oscar Mayer hot dogs and Cheez Whiz.