Kellogg's has apologised to a Jewish man who ate a cereal bar containing pork gelatine because its wrapper incorrectly stated it was suitable for vegetarians.
Oberon Gardner and his family bought the Rice Krispies Squares bars at a supermarket in Colchester, Essex, last week.
Labels on 5,000 multipacks carried the words "suitable for vegetarians", even though the full ingredients list explained that around one per cent of the marshmallow bar contained pork gelatine.
It was only later that 21-year-old Mr Gardner inspected the individual wrapper more carefully.
"After my sister ate one bar and I took a bite of mine, it occurred to me that I had never seen any marshmallow without some form of gelatine in," he said.
"I decided before I ate any more to see what was substituted in its place. I was absolutely disgusted to find that the ingredients list stated it had pork gelatine in it. I felt so sick. I have been vegetarian all my life, so it was a real shock to the system.
"When I rang Kellogg's, they were at first very rude and said I was lying, but then they went away and discovered it was on all the multipack wrappers."
Mr Gardner was offered a refund.
A Kellogg's spokeswoman said: ""We've been speaking with the Gardners all week who have been considering what kind of offer would make up for their disappointment and we're pleased to say we settled the matter to their satisfaction yesterday.
"We would like to apologise sincerely to the Gardner family. We have a strict quality-control process in place and labelling issues are extremely rare."
She said the company halted production after being made aware of the error and now plans to cover the "suitable for vegetarians" label with stickers on remaining misprinted packs.
The company also contacted the Manchester Beth Din in an attempt to understand the implications of the incorrect labelling.
A spokesman for the Beth Din said: "At no time did Kellogg's portray the product as kosher - and any consumer worried about their consumption of kosher food should not buy items which only state ‘suitable for vegetarians'.
"They should look for a kosher logo on the packaging or take guidance from the correct kosher authorities."
The kashrut division of the London Beth Din lists all Kellogg's cereal bars as not kosher.