(UPI) A grocery store chain said it is investigating after an Australian customer found a venomous snake inside the plastic bag with her pre-packaged lettuce.

Lesley Kuhn of Mosman, a Sydney suburb, posted photos to the Facebook group Mosman Living showing the pale headed snake -- a venomous species -- her son found inside the package of lettuce the family bought from Aldi.

"Check packaged lettuces carefully," Kuhn wrote.

Aldi officials said they are investigating the discovery with help from wildlife rescue charity WIRES, which is currently caring for the snake and is planning to release it back into the wild.

"We've worked with the customer and the team at WIRES to identify the snake's natural habitat, which is certainly not an Aldi store," the grocery chain said in a statement.

The statement said the store is attempting to determine how the snake came to be inside the lettuce package.

"We are working closely with our produce supplier to investigate how this incident could have possibly occurred," the chain said.

WIRES spokesman John Grant said the incident was highly unusual.

"We've never seen anything like this," Grant told the Australian Broadcasting Corp.

"We assume, and it's only an assumption, that because it was a juvenile it was picked with the lettuce and it's survived the whole process."

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