Fitch analysts said in a report that "growth trends remain challenging" for Kraft Heinz and other large food companies "due to brand maturity and changing consumer preferences."
Kraft Heinz had no comment when CNN Business was asked about the Fitch report.
A downgrade to rubbish would be bad news for Kraft Heinz, a global giant selling dozens of food brands such as Kool-Aid and Jell -O in addition to namesake cheese and ketchup products.
Lower credit ratings make life financially tougher for debt-laden companies because it increases interest expenses. Kraft Heinz had almost $ 30 billion in debt, as of June. Companies with poor credit ratings often also find it more difficult to raise more money by selling new bonds.
Warren Buffett harmed by the problems at Kraft Heinz
Both S&P and Moody's also have Kraft Heinz's debt rated at a level above the rubbish territory. S&P downgraded Kraft Heinz in June, citing "reduced" outlook for the company's brands.
Kraft Heinz has struggled to adapt to changing consumer tastes in recent years.
The company has focused more on cost cutting and less on introducing innovative new food products. This is a key reason why earnings and sales have fallen.
Kraft Heinz has also had to handle an accounting probe from the Securities and Exchange Commission and the company has recently reworked earnings from 2016, 2017 and parts of 2018 after an internal review of the books.
But will it be too little too late?
Kraft Heinz has made many write-downs over the past year to reflect the lower value of carrier products such as Kraft macaroni and cheese, Oscar Mayer lunch, Miracle Whip, Philadelphia cream cheese and Maxwell House coffee.
Kraft Heinz shares fell 2% on Monday and the stock is now down 40% this year. The jump has wiped out more than $ 5 billion in the value of Berkshire Hathaway's stake in Kraft Heinz.