Kellogg's has stopped using rice grains in Rice Krispies and Coco Pops sold in the United Kingdom, and is using corn flour and rice flour instead.
A company spokesperson told the BBC on Tuesday that the change was made because of "changing weather conditions" that have disrupted supplies, and that the updated recipes had been "carefully assessed" with customer feedback taken into consideration.
Rice crops have been hit by dry weather in key producing countries in Asia, reducing harvests and driving up prices. Most of the world's rice comes from Asia, and parts of the region have been affected by drought, flooding and heat linked to El Niño. South East Asia alone produces more than a quarter of the world's rice. The BBC reported that the World Meteorological Agency expects the record-breaking El Niño to last until at least 2027.
The recipe change means the packaging will now carry a "contains wheat gluten" warning.
The company said the new recipes will help "maintain consistent quality at a time when changing weather conditions are affecting the quality and availability of some of the rice and grains used in our cereals". It added: "We appreciate that even small changes to a much-loved product can feel noticeable and that's why we have approached this with a lot of care and consideration."
Both cereals will continue to meet UK food standards on levels of fat, salt and sugar, the company said. They contain no artificial colours, flavours or sweeteners, and the nutritional content of each bowl, including fibre, vitamin D and iron, is unchanged.
Rice Krispies in the United States and Canada will continue to be made with real rice, with no changes to those recipes expected, a spokesperson for Kellogg's North American business told the BBC.
The Kellogg company separated into two firms in 2023. The larger part, Kellanova, sells snacks, cereals, noodles and other products including Pringles and Pop-Tarts, and is now owned by Mars. The North American business, WK Kellogg's, has since been taken over by Ferrero.
The change is smaller than it sounds and larger than it looks. Nothing about the cereal's name has altered. What has altered is the job the name is doing.
Until Tuesday, "Rice Krispies" described an ingredient. It now describes a shape, a noise and a historical association with a crop grown several thousand miles away in better years. This newspaper believes it to be the first British breakfast product named after the weather.
The labelling bears this out. The one new declaration on the packet is a warning about wheat gluten, a grain that appears nowhere in the name. The grain that does appear in the name survives in the recipe only as flour.
The geography is the part our analysts find most instructive. The same two words now denote a cereal containing rice grains in Winnipeg and a cereal containing corn flour in Coventry, with no change to the words themselves. Crossing the Atlantic currently alters the contents of the packet, and nobody has to be informed.
The Department of Unnecessary Research accepts that the recipe was changed to protect consistency, and notes that consistency has indeed been protected. The cereal is the same on Tuesday as it was on Monday in the one respect the company fully controls, which is what it is called. Forecasters expect the El Niño to persist until at least 2027, which gives the name another year in which to describe a grain it no longer contains.