PhoenixDuctClean

Diagnostics & problems / Mould

Mould in commercial kitchens: where it starts, how to stop it

Wiping the mould off is the easy part. Unless the damp feeding it is dealt with, it is back within weeks.

Damp
the real cause
Sealant
and voids
Deep clean
strips it back
SPORES
TR19 certificate Before & after photos Filters degreased Fully insured EHO accepted

The part everyone gets wrong

Removing mould is the easy bit

Mould in a kitchen looks like a cleaning job, and the visible growth genuinely is easy to remove. The reason it defeats people is that it comes back - often within a few weeks, in the same spot. That is the tell: mould is not really a dirt problem but a moisture one, and wiping the growth away without touching the damp that feeds it simply schedules the next appearance.

To stop it, you have to know where and why it starts.

Where it takes hold

Seams, seals and cold surfaces

Mould needs moisture, warmth and something organic to feed on - all abundant in a busy kitchen. It establishes first in the places that stay damp and undisturbed: the silicone sealant along sinks and worktop junctions, where microscopic cracks trap water and grease; the rubber seals of walk-in fridges and freezers; and cold surfaces where warm, humid air condenses - wall junctions, the backs of units, above suspended ceilings. Once it penetrates a sealant bead, surface cleaning no longer reaches the colony inside.

These are exactly the spots a daily clean passes over.

Why it matters

More than a stain

It is not only unsightly. Mould releases spores and allergens that can trigger coughing, wheezing and asthma, and prolonged exposure carries a genuine respiratory risk for staff - which is why it is treated as a workplace health issue, not just a food-safety one. Recurring black mould on sealant is also a signal in itself: it flags a persistent damp or ventilation fault behind the surface that will keep producing growth until it is corrected.

Moisture
the real fuel
Sealant + seals
first to go
Spores
a health risk

Stopping the return

Strip it back, then fix the source

A deep clean does two things a wipe cannot: it removes the colony properly, including the grease and organic film it feeds on, and in doing so it exposes the source - the failed sealant, the condensation point, the poorly ventilated void - so it can be corrected. Where a sealant bead is colonised through, the lasting answer is to cut it out and re-seal, not to keep bleaching it.

So removing visible mould is necessary but not sufficient. Unless the moisture or ventilation source feeding it is found and fixed, it returns - and a deep clean is what strips the growth back and reveals the cause so the cycle can be broken.

Questions

Frequently asked questions

Why does mould keep coming back after I clean it?

Because the growth you remove is the symptom, not the cause. Mould feeds on moisture, so unless the damp source behind it - a failed seal, condensation or poor ventilation - is fixed, it returns, often within weeks and in the same spot.

Where does mould usually start in a commercial kitchen?

In the places that stay damp and undisturbed: silicone sealant along sinks and worktops, the rubber seals of walk-in fridges and freezers, and cold surfaces where humid air condenses, such as wall junctions and the backs of units.

Is kitchen mould a health risk?

Yes. It releases spores and allergens that can trigger coughing, wheezing and asthma, and prolonged exposure is a genuine respiratory risk for staff - which is why it is treated as a workplace health issue as well as a food-safety one.

Why can't I just bleach the sealant?

Once mould penetrates the microscopic cracks in a sealant bead, surface cleaning no longer reaches the colony inside, so it returns. Where a bead is colonised through, the lasting fix is to cut it out and re-seal.

How does a deep clean stop mould?

It removes the colony and the organic film feeding it, and exposes the source - the failed sealant, condensation point or poorly ventilated void - so it can be corrected. That breaks the cycle a surface wipe only postpones.

20+ Years of Experience

Phoenix Duct Clean · by the numbers

Kitchen canopies
degreased
4,287
Laundry ducts
cleaned
1,877
LEV systems
tested
1,658
Hours
on site
54,754

Stop the mould coming back

We strip the mould and the organic film it feeds on, and flag the damp or ventilation source behind it. Ask us for a survey and a quote.