Enzymes

If the label says "enzymes", "bio" or "stain-removing enzymes"

Enzymes are proteins that cut particular stains into pieces small enough to wash away: protein (blood, egg, grass), starch, fat, and gums. They work at low temperatures and in tiny amounts, typically 0.002% to 0.1% of the product.

In Europe, enzymes must always be listed on a detergent label, whatever the amount. Australian cleaning products don't have to list all their ingredients. Only a scheduled poison must be named on the label, with its strength, and a disinfectant must name its active ingredients. So a label can say "enzymes" or nothing at all.

The main risk is breathing them in, not touching them. Several detergent enzymes are officially classed as causing allergy or asthma if inhaled. That's a breathing allergy, so it doesn't earn the ⚠ skin-allergen badge, but it's the worst fact for most of this chapter. The people who've been hurt were mostly factory workers. Consumer cases were linked to the dusty powders of the late 1960s. Being "sensitised" means your immune system has made antibodies; not everyone sensitised gets symptoms.

Cheat sheet

☠ Poison schedule (Australia) · ⚠ Officially classed skin allergen · 🛢 Made from a hazardous chemical · 💧 Contaminant risk

The chemicals

• Protease
• Amylase
• Lipase
• Cellulase
• Mannanase
• Pectate lyase

The big myth: "bio" detergents and sensitive skin

In the UK, Ireland and Australia, "non-bio" detergents have long been sold as kinder to sensitive skin. A 2008 review by a toxicologist and three UK dermatologists found no evidence for it, calling the supposed effect on skin "a consequence of a mythology". When 80 people with rashes they blamed on enzyme-washed clothes, and 60 other consumers, were patch-tested with protease, none reacted. Proteins are too large to cause the usual kind of skin allergy, though rare cases of hives from handling raw enzymes have been reported, mostly in workers. (The review's lead author has since written enzyme-safety reviews funded by the detergent and enzyme industries.)

Safer alternatives

In 1913 the German chemist Otto Röhm patented the use of digestive enzymes from animal pancreas to lift dirt from laundry, and his soaking powder, Burnus, went on sale in 1914. The first bacterial enzyme, a protease called Alcalase, went into the soaking powder Bio-tex in 1963. After factory asthma around 1970 sparked a US press campaign about the risk to consumers, sales collapsed until a US inquiry found no consumer risk and dust-free granules brought them back, though as late as 2000 a modern European factory using only granules had an asthma outbreak as large as those of the 1960s.

Look for these:

• Modern granular powders, liquids, gels and pods, all of which release only tiny traces of enzyme in normal use. Pour powder gently and don't breathe in the dust.
• With spray stain removers containing enzymes, spray away from your face.
• Keep pods away from children: one US eye hospital saw 10 children with eye injuries from liquid pods in 9 months (from the detergent itself, not specifically the enzymes).
• Non-bio, if a doctor has confirmed you're allergic to a detergent enzyme, or you already react to enzymes at work.