Food giant Heinz has revealed that its No Added Sugar Beans are not suitable for vegans.
The beans - which are used in a couple of meals by budget pub chain Wetherspoons - contain an ingredient that is derived from animals.
As yet, Heinz has not confirmed what this ingredient is.
A spokesman for Heinz said: "Our standard Heinz beans are perfectly suitable for vegetarians (and vegans) as are our reduced sugar and salt beans. And while our new no added sugar Heinz beans are also suitable for vegetarians the recipe is not vegan.
"Hope this clarifies that Heinz beans are indeed vegetarian-friendly wherever you choose to enjoy them."
"The Heinz Beanz Wetherspoons serve are just the same as you buy in store and are perfectly vegetarian-friendly."
A statement released by JD Wetherspoon said: "Heinz has informed Wetherspoon that the low sugar beans are not suitable for vegans.
"The only meals affected are jacket potato with beans (adult and children’s meals) as we claim that they are both vegan meals.
"Amended dietary menus will be reprinted and sent to pubs."