This mum was cleaning her children's lunchboxes. What she found disgusted her.

When Grace Bollen was finished cleaning her children’s lunchboxes two weeks ago, she made a discovery that would leave any parent feeling sick.

As she was cleaning she saw a tiny spot of black in the corner, prompting her to open a glued down part of the lunchbox.

As she pried open the plastic cover, she found that there had been huge amounts of mould growing underneath, in a part of the lunchbox that she couldn’t access and therefore clean.

Horrified at what she had just discovered, Grace swiftly shared the discovery on Facebook to warn other parents.

“So today, something in me prompted me to pry open the glue in the kids’ lunchboxes,” she began.

“I saw a little black spot in the corners while washing. This is what I found. I’m absolutely appalled. I feel awful that my children have been eating lunch out of these,” she continued.

Accompanying the text, Grace shared images of lunchboxes which were completely covered in mould.

“The children’s lunchboxes have been hand washed each night & left open to dry. Blue lunch box has been used for around 9months. Yellow for about 12months,” she wrote.

Finally, she added some advice for other parents.

“Don’t buy any lunchboxes that you can’t clean ALL the parts. Feel free to share. Parents need to know!” she wrote.

In a later edit to the post, the mother added that she had been in touch with the company, and that they were working to make the product watertight.

She added that you can see mould through a lunchbox by holding it up to the light, so you don’t have to pull the product apart to check.

According to the Centre for Disease Control and Prevention, exposure to mould is usually unharmful.

However for those sensitive to mould or who have a weakened immune system, exposure can have a terrible effect on their health, so it should therefore be avoided at all costs.