What is the blue mould on food?

It is most likely Penicillium. Blue-green colour with a white growing edge.

Is blue mould on food dangerous?

Public health guidance is to remove indoor mould regardless of species, so the answer does not hinge on identifying it. Fix the moisture source or it returns.

Blue mould on food

Mostly seen on food. Blue-green on bread and citrus is Penicillium.

1 likely answer.

The species matters less than you think

Public health guidance is to remove all indoor mould regardless of type. The CDC and EPA do not recommend routine species testing for ordinary households, because the response does not change: find the water, stop it, remove the growth.
“Toxic black mould” is a marketing phrase, not a category. Stachybotrys is real and does need soaked material to grow, so finding it tells you something useful about your building. But the health effects that are well established — allergy, asthma aggravation, irritation — are not specific to it.
Mould without water does not persist. Cleaning growth while leaving the moisture source is why it comes back. The leak, the condensation or the ventilation is the actual problem.

Call a professional for areas larger than about 10 square feet, for anything in HVAC ductwork, after sewage or flood water, or if anyone in the household is immunocompromised or has a lung condition.

The likely answer

1.Penicillium

Routine

Blue-green or grey-green powdery colonies with a characteristic white fringe at the growing edge, and a texture like fine felt. On food it is the familiar blue-green fuzz on bread and citrus.

How to know it is this one

Blue-green colour with a white growing edge.

What it means: Recent or ongoing water damage, or humidity high enough to keep soft materials damp. Materials that have been wet for more than 48 hours generally need replacing rather than cleaning.

Still not sure?

The key adds texture and surface, which separate these far better than colour does.

Identify it step by step