What is the white mould in the kitchen?

There are 2 likely answers: Penicillium, Surface Mildew. Blue-green colour with a white growing edge.

Is white mould in the kitchen 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.

White mould in the kitchen

Often the early stage of something that will darken later, and often not mould at all — efflorescence on masonry is white and crystalline.

2 likely answers.

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 2 likely answers

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.

2.Surface Mildew

Routine

A flat, superficial film of black or grey speckling on grout lines, silicone sealant and painted surfaces. It sits on the surface rather than penetrating, and it wipes away with a cloth.

How to know it is this one

Flat and superficial. Wipes off, leaving clean material underneath.

What it means: Inadequate ventilation. If it comes back within a fortnight of cleaning, the extractor fan is undersized, not vented outside, or not run long enough.

Still not sure?

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

Identify it step by step