The assistant manager reportedly said the battery came from a food thermometer, but Weston said she and her partner were not shown the instrument.
She told the ABC the pair called the Poisons Information Hotline and were warned they might need to go to the hospital if they could not identify the origin of the battery.
Weston posted a photo of her unfortunate food find on Facebook with the caption: “Well, I’m not eating Guzman y Gomez Ripley again, I found a battery in my burrito bowl and they think voucher makes up for almost poisoning myself.”
The batteries can cause chemical burns and internal injuries, which can be life-threatening if ingested.
Guzman y Gomez told Australian media it had “been in contact with the guest who was involved”.
“GYG immediately initiated a full investigation into this matter and confirmed that the object came from a food-grade thermometer.
“We have undertaken urgent actions to ensure that this does not happen again, which includes the replacement of this model of thermometer, training of crew and additional checks of our equipment across all our restaurants.”
Guzman y Gomez said it takes incidents of that nature “extremely seriously” and that food safety was an absolute priority.
The restaurant also said it was an isolated incident and no alert or recall was required.
Guzman y Gomez has more than 200 stores across Australia, Singapore, Japan and the United States.
The restaurant, which has the majority of its outlets in Australia, has no New Zealand stores.
