Mould decontamination of a brewery production building, after an earlier clean-up failed

What we found

A brewery’s production building had mould contamination return within a couple of months of a previous firm’s clean-up work. The extent of the regrowth pointed to the earlier removal protocol not having addressed the underlying cause, and possibly having spread spores further during the work itself.

We carried out an environmental survey to establish why. Psychrometric testing recorded significant condensation across surfaces throughout the building, identifying this as the main contributing factor to the mould growth. Indoor air quality particulate testing showed ambient levels were within acceptable limits, but ATP testing of surfaces found high levels of microbial activity, and laboratory analysis of tape-lift samples under DMA microscopy identified several mould species (including Penicillium, Aspergillus flavus, Aspergillus niger and Cladosporium) at concentrations consistent with the visible contamination and pointing to a need for remedial action.

Interior of the brewery production building, showing stainless steel tanks and wrapped oak barrels awaiting decontamination

Psychrometric meter reading taken during the environmental survey — Psychrometric testing

Indoor air quality particle counter reading taken during the environmental survey — Indoor air quality testing

ATP luminometer reading taken from a wall surface during the environmental survey — ATP surface testing

Tape-lift sample under microscope, taken from the structural frame — Sample from structural frame

Tape-lift sample under microscope, taken from a timber vessel — Sample from a timber vessel

Penicillium identified under microscope from a tape-lift sample — *Penicillium*

Aspergillus flavus identified under microscope from a tape-lift sample — *Aspergillus flavus*

Aspergillus niger identified under microscope from a tape-lift sample — *Aspergillus niger*

Cladosporium identified under microscope from a tape-lift sample — *Cladosporium*

How the works were delivered

Assess: an environmental survey combining psychrometric testing, indoor air quality particulate analysis, ATP surface testing and laboratory DMA microscopy to establish the extent of the contamination and its root cause.
Verify: laboratory analysis of tape-lift samples confirmed the mould species present and the level of contamination requiring remedial action.
Remediate: a sealed, negative-pressure containment zone around the structural frame and timber vessels; visible mould removed from structural surfaces by dry ice blasting; timber vessels HEPA-vacuumed; surfaces treated with our OXID-8/B-RINSE two-stage decontamination method; SteraMist treatment of surfaces and air.
Clear and report: indoor air quality testing throughout the works, followed by laboratory spore trap and ATP clearance testing before sign-off.

Timber vessels before decontamination, stacked in racking — Before decontamination

Timber vessels after decontamination, stacked in racking — After decontamination

A technician in full PPE applying SteraMist treatment to caged bottles — SteraMist application

Addressing the underlying cause

The environmental survey had identified condensation as the main contributing factor to the mould growth. Additional ventilation brought moisture levels under better control alongside the decontamination works, addressing the condition that had allowed the earlier contamination to return.