A woman said she felt "physically sick" after allegedly finding a stomach-churning ingredient in her sandwich.
Faye Wood, a healthcare assistant at the Queen's Medical Centre, told of her shock when she spotted a caterpillar crawling live in her sandwich bought from a Sainsbury's store.
The 27-year-old from Mapperley said it happened when she went to her local store in Ransom Road to grab a quick snack after finishing her shift.
Ms Wood said she went for a Ploughman's sandwich which she picked from the reduced section at around 7pm before continuing her journey.
She said she had half of the sandwich shortly after she arrived home, and then left the other half in the fridge, Nottinghamshire Live reports.
Ms Wood said the caterpillar was "crawling out of the sandwich and out of the packaging"
Nottingham Post / BPM Media)
It was not until 30 minutes later when she reached to the remaining half in the packaging that she noticed the "shocking" discovery.
Ms Wood added: "My two-year-old wanted to taste it so I grabbed it from the fridge and when I saw it I started heaving – I was physically sick.
"It was a big caterpillar crawling out of the sandwich and out of the packaging.
"I never had a problem before so it was a shock for sure."
The angry customer has vowed to "never buy sandwiches from supermarkets ever again" following the incident.
She added: "When you have been at work all day and you get back at 7 you do not really want to cook, you just want a snack or something.
"I have never had a problem with sandwiches – I do get them quite a lot. But this is unacceptable.
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"I will never buy sandwiches from supermarkets ever again because it has really put me off and I will just be thinking about that all the time."
Ms Wood submitted a complaint to Sainsbury's on November 22 with a video of the caterpillar crawling on the sandwich packaging.
She added: "I am not bothered about the money really because it was only 54p.
"It is more about making people aware that this is happening and it cannot happen again.
"We just want them to make sure that everything is checked and washed properly.
"However I do expect some kind of compensation as well."
A Sainsbury’s spokesperson said: “Cases like this are extremely rare because we have processes in place to prevent them from happening.
"We are contacting Faye to apologise for her experience and we are investigating with our supplier.”