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Can washing at ambient temperatures really kill bacteria?

23 May 2016

For more than 60 years, it has been the ‘norm’ for commercial laundry operations and hotels processing linens on site to wash at high temperatures using a combination of fabric agitation and large amounts of detergent. But when you consider the impact this method could be having on your business, is this really the most effective way of achieving cleaner looking linens whilst killing bacteria? Steve Jenkins, chief scientific officer at Xeros, looks at the alternatives

Commercial laundry operations and hotels will be familiar with the problems associated with washing at high temperatures which can have an impact on a company’s bottom line. For hotels, harsh washing processes can prematurely wear out linens increasing the business’ linen replacement costs. For professional laundry operators, poor fabric care can lead to customer complaints and even lost business.

In a standard commercial laundry’s wash cycle, fabrics are immersed in hot water and the heat contributes to the wash cycle’s ability to extract soil from the fabrics. However, just as high temperature water extracts soil from fabrics it also contributes to wear and tear. The heat of the water damages the threads and can also contribute to colour bleed in the wash.

Traditional laundry methods also rely on a rough agitation cycle to beat fabrics in the wash clean. The rough ‘drop and slop’ motion of this cycle puts further stress on fabrics already weakened by hot water. In addition, these types of laundry processes also require copious amounts of chemicals. The more chemicals fabrics are exposed to, the more wear and tear they experience. 

But it does not end there. Traditional laundry operations use copious amounts of water, so in order to get this up to temperature, a lot of energy is required. More energy usage means higher bills.

Polymer bead technology

However, it is possible to kill bacteria by washing at ambient temperatures if a polymer bead laundry system is used; thereby conserving energy and reducing linen loss. We carried out a scientific study to prove that this system has the ability to perform low temperature washing with the same level of hygiene as conventional high temperature washing. It also cuts the amount of water needed by 80%.

To perform our study we added five different types of bacteria commonly found in dirty laundry wash loads to several cotton cloths. The bacteria strains were; Staphylococcus Aureus, Pseudomonas Aeruginosa, E Coli, Enterococcus Hirae and Klebsiella Pneumoniae. Each bacteria strain was added in equal amounts to a separate cloth and for the purposes of this experiment, we went heavy on the amount added.

The next step was to wash these infected pieces of fabric in separate groups. One batch was washed in a machine that uses a polymer bead washing system, and the other in a conventional aqueous machine. In both cases, biological detergent was added to the machines at the start of the wash. An additional hygiene agent was used in the second rinse of the polymer bead washing system. The crucial differences between the two systems was the reduced water temperature and the amount of water used.

The washing machine that uses polymer bead technology washes at 68 degrees Fahrenheit in contrast to the industry standard hot water wash of 149 degrees. But in order to fully explore this issue, we tested various different scenarios; a polymer bead machine running at 104 degrees and 149 degrees with varying additions of cleaning agents. We also tested bacteria-infected cloths using different cleaning agents in the conventional washer.

After washing, the cloths were set aside in ideal bacteria growing conditions for between one and three days. The number of bacteria present were then counted to see how many had grown back. Our findings indicated the disinfecting efficiency of a polymer bead washer using lower temperature water and a hygiene agent effectively killed bacteria at a 99.9999% rate for four bacteria types and at a 99.99% rate for Pseudomonas Aeruginosa. This rate was comparable to conventional hot water washing.

By switching out water for polymer beads you can reduce your reliance on hot water to get the job done. For sanitizing fabrics, special chemical detergents are used with polymer beads to disinfect them. The end result is a significant savings on energy utilities that would once have been consumed to heat 100 or more gallons of water in a commercial-sized wash load. Even better, the polymer beads cut water use by up to 80%, greatly reducing the water consumption of your laundry operation.