Do You Really Need Laundry Sanitiser? Experts Say Only in Specific Situations

The product sits in a lot of Australian laundries, poured into the fabric softener compartment or straight into the drum during the rinse cycle. Laundry sanitisers are usually sold on a single promise: they remove 99.9 per cent of bacteria, including the kind that cause odour, along with viruses. They are growing in popularity. Two university experts who spoke to nine.com.au say they shouldn't be part of a regular routine.

Associate Professor Saniyat Islam, of RMIT University's School of Fashion and Textiles, explained how they work. Most household products are rinse-cycle additives built on quaternary ammonium compounds, known as quats, such as benzalkonium chloride. Quats carry a positive charge and are drawn to the negatively charged outer membranes of bacteria. Once attached, they disrupt the membrane, the cell contents leak out and the microbe dies. That makes them effective against flu, coronavirus and most bacteria. They do not work on bacterial spores or on norovirus, which causes gastroenteritis.

The cost of that action is what stays behind. Islam said quats deposit on fabric much as fabric softener does. Over time, towels can become less absorbent and technical sportswear can lose its moisture-wicking performance. The residue and added fragrance can also irritate sensitive skin or aggravate conditions such as eczema.

For most loads, the experts say, the product isn't needed. Washing removes most microbes, and drying removes more, particularly when clothes hang outside in the sun. Islam said adding sanitiser to every load means extra cost, extra chemicals going down the drain and more residue on fabrics and skin, with little added health benefit for most people. He also raised regular, low-level use of antimicrobials as a concern because of its contribution to antimicrobial resistance.

There are situations where it earns its place. Islam named a household member who is unwell with an infection, someone who is immunocompromised, elderly or a newborn, items soiled with bodily fluids, and shared or communal machines. It also makes sense when something that would normally go in a hot wash has to be cleaned cold because of fabric or care-label limits. The exception is gastro: after a case in the household, a hot wash is more effective against that virus, given how sanitisers work.

Alternatives exist. Islam said washing at 60 degrees or above with a good detergent is among the most reliable options for towels, sheets, underwear and cotton items that can take the heat, and many machines have a dedicated hygiene or sanitise cycle. He also recommended oxygen bleach (sodium percarbonate) in warm or hot water for colour-safe items, and chlorine bleach for white cotton or where the care label allows.

Many people buy sanitiser for smell. Associate Professor Cindy Gunawan, of the Australian Institute for Microbiology and Infection at the University of Technology Sydney, said that has a rational basis. Persistent odours on towels, sportswear and synthetic fabrics often come from bacteria that survive ordinary washing, such as Moraxella species, behind the "wet towel" smell. Killing them can reduce or eliminate the odour. But she said sanitiser is not a complete or always necessary fix, because it does not remove dirt, oils or sweat residues. Islam added that unless the oil is removed, the smell tends to return once the garment warms against the body.

The experts' suggestions for odour include a hot wash where the fabric allows, half a cup of white vinegar in the rinse cycle or half a cup of baking soda in the wash, enzyme-containing detergents, and pre-soaking in oxygen bleach. Moving washing to the line or dryer promptly after a cycle helps, as does washing sweaty items quickly or at least airing them before they go in the hamper. The advice points toward saving sanitiser for the specific cases above.