Excess Mould

Excess mould is surface growth that has gone beyond what is wanted, in one of two ways. The first is simply too much of the right mould: the noble white bloom grown so thick and matted that it clogs the casing, holds moisture against the surface and interferes with even drying, rather than sitting as the light, even coat that is the aim. The second, and the more serious, is wild mould taking hold, the patchy greens, blues, blacks, reds and fuzzy greys that are not the noble strain at all. It presents by eye and by texture: a heavy felted white layer in the first case, or off-colour patches, a hairy or fuzzy growth, and sometimes a musty or sour smell in the second.

The mechanism is a surface that has been left to grow whatever the conditions favour, rather than being steered. Mould needs moisture and still, humid air, so a surface held too damp, in a chamber run too humid or with too little air exchange, grows mould fast and thick, whether noble or wild. Whether the growth is the safe noble strain or a wild coloniser is decided by what establishes first and what the conditions favour. Left to chance, wild moulds present in the air or on the equipment can settle and spread across the rind.

**How it endangers cured meat.** The danger in excess mould is not the thickness of a noble coat, which is a quality problem, but wild colonisation, which is a safety one. Some wild moulds produce mycotoxins in the meat itself, and the one that matters most on cured meat is Penicillium nordicum, which makes ochratoxin A, a stable, nephrotoxic mycotoxin that is not removed by later processing. The hard part is that Penicillium nordicum forms a pale surface growth that closely resembles the noble white Penicillium nalgiovense, so a white coat is a reassuring sign but not an absolute guarantee of safety, and reliable separation of the two needs a laboratory. This is exactly why Mould Control treats the surface as a decision rather than an accident: the safe route is to establish a known noble strain deliberately rather than to trust that whatever grows is benign. Off-colour wild growth is the clear warning; a look-alike white is the subtle one.

The usual causes are humidity held too high, poor air circulation leaving the surface damp, no noble inoculation so the surface is open to whatever settles, and a contaminated chamber or equipment carrying wild spores. A chamber that has grown wild mould before will tend to again unless it is cleaned and re-seeded with the noble strain.

**How to avoid it.** Steer the surface rather than leaving it to chance. Inoculate with a known noble strain, chiefly Penicillium nalgiovense, so it establishes first and holds the surface by competitive exclusion, the mould equivalent of a starter culture inside the sausage. Hold the humidity so the noble coat stays light and even rather than thick and matted, give the chamber enough gentle air exchange that the surface is not left sodden, and keep the chamber and equipment clean so wild spores are not seeded from a previous batch. A light, even white bloom is the target, not a heavy felt.

**How to fix it.** A coat that is merely too thick can be brushed or wiped back to an even bloom. Wild growth is a different matter and calls for judgement. Caught very early and small, a patch of green or blue wild mould can often be wiped away with a cloth dampened in a mild vinegar and water solution, around one part vinegar to nine parts water, and the piece returned to better-managed conditions; where it is a little more established the affected area can be cut back below and around the growth before wiping, since mould can penetrate a still-moist surface. Wipe the wild growth in a targeted way rather than scrubbing the whole piece down, since the aim is to lift the unwanted mould while leaving the beneficial white bloom you want to keep. Black, red, slimy or heavily fuzzy growth, growth that smothers the piece, or anything with an off smell, is not worth the risk: discard the product. Because the toxigenic look-alike cannot be told from the noble strain by eye, do not rely on colour alone as proof of safety, and treat the real fix as prevention: a deliberate noble inoculation and a well-managed surface so wild growth never gets its chance.

Excess mould sits on the Mould Control Pillar and is the failure the Pillar exists to prevent. It is the flip side of surface-mould management, the ongoing discipline of keeping the right mould on and the wrong mould off, and it connects to the noble strain Penicillium nalgiovense, the toxigenic look-alike Penicillium nordicum, and the mycotoxin ochratoxin A that is the reason the distinction matters.