She said: "I decided to cut into Sophie out of curiosity and discovered a science experiment living inside. Smelly, ugly mold living in my infant's favorite chew toy!"
The toy has been a favourite with parents - and gift buyers - for generations and is made of 100 per cent natural latex from Hevea trees, making it ideal for children to bite on to ease the pain of teeth coming through.
Like a dog's toy, it has an airhole in the bottom of the toy to let children squeeze it.
The toy has regularly been seen being used by celebrities, with Miranda Kerr and Orlando Bloom's son Flynn a fan when he was younger. Other celebrity Sophie converts include Kate Hudson, Maggie Gyllenhaal Nicole Richie, Isla Fisher and Amy Adams.
Created by French company Vulli, it was first brought to the market in 1961 and is often recommended by health professionals for its easy-to-grasp shape.
Another user, Stephanie Oprea, last year posted similar images of mould growing inside her child's Sophie the Giraffe.
On an Amazon review, she wrote: "Beware! If you have a drooly baby, moisture will get in the hole and you'll end up with mold! We've had ours for two years and the entire inside is coated with black mold!"
Elsewhere, another owner of the toy, thought to be from the US, posted a similar review after she chopped off the legs of the toy to stop her daughter pushing them too far into her mouth.
She wrote: "I thought we'd be smart and cut the legs, so they weren't so long. Well, when we chopped the legs, it revealed a lot of mold growing inside!! Needless to say, Sophie is now residing at her new home at the dump.
Just a little heads up to other moms who have this toy. Sorry my photography isn't great, but you can clearly see the mold."
A spokesperson for Vulli told Femail that the cleaning instructions for the toy must be "carefully respected."
They said: "It's important to know that Sophie la girafe [the toy's French name] is composed of 100% natural rubber, so the cleaning instructions have to be carefully respected.
"As indicated on the packaging and in an explanatory leaflet inside the packaging, we recommend to clean the surface of Sophie la girafe with a damp cloth. It should not be immersed in the water nor rinsed off, to prevent water from getting inside, as she may become damaged.
"We thus would like to emphasize on the fact that is it important, while cleaning the product, that no water gets inside the whole."
The company said it had not received complaints about similar incidents but that it would take them "very seriously" adding "For the past 55 years, we have always strived to exceed security standards and all of our products comply with the most stringent global standards."