14th January 2021 – (Hong Kong) The Consumer Council announced in the new monthly issue of “CHOICE” that after testing 15 multi-purpose disinfectant sprays, it was found that the performance of the sterilisation and virus elimination of the samples was poor, of which 80%, or 12 samples, performed poorly when compared with 75% disinfectant alcohol and 1:99 diluted bleach solution. The Consumer Council has also found that some samples have extremely low sterilisation ability and call for caution when using disinfectants, otherwise they will affect the skin and even contaminate food. The Consumer Council tested 15 multi-purpose disinfectant sprays, including 9 hypochlorous water, which use hypochlorous acid as the active ingredient, with concentrations ranging from 50 ppm to 210 ppm; the other 3 are chlorine dioxide or oxychloride products and 3 disinfectant sprays made of plant extracts.
Test samples include the effectiveness of sterilisation and elimination of virus infection, effective chlorine concentration, pH value, and evaluation of the stability of related ingredients in the product. The test results show that 9 types of hypochlorous acid water generally perform better against the tested viruses, and the sterilisation effect is also quite good. However, if used in daily life environment, the sterilisation and anti-virus effect of these products will be affected by the stability of their formulations, acid and alkaline level.
The 15 multi-purpose disinfectant sprays all claim to have the ability to kill bacteria. However, in terms of the effectiveness of killing E. coli K12 and Staphylococcus aureus, there are 7 samples with very different performance in killing the two test bacteria. The killing rate was from 14.286% to 72.347%, and the killing rate for Staphylococcus aureus was from 11.111% to 98.956%. Among them, the two samples with chlorine dioxide as the main component showed the worst sterilisation effect, and the killing rate against both test bacteria was less than 28%. In terms of performance in eliminating adenovirus infectivity, only 2 samples in the test showed satisfactory performance in eliminating adenovirus infectivity, and the performance of the other 13 samples in eliminating adenovirus infectivity ranged from 0% to 96.20%. One of them has no inhibitory effect on adenovirus, it has the lowest bactericidal efficacy among the tested samples.
In addition, two samples with a bactericidal efficacy of more than 99.999% showed only 18.72% and 0% virus elimination efficacy. The Consumer Council also used 75% disinfectant alcohol and 1:99 diluted bleach solution prepared according to the formula recommended by the World Health Organization to achieve a 99.999% sterilisation rate against the two test bacteria, and the effectiveness of inhibiting adenovirus infection was also different from 87.98% and 99.83%. The Council pointed out that the comprehensive test results showed that only three hypochlorous acid samples have the same sterilisation and virus elimination effects as alcohol or diluted bleach.
The price of disinfectant sprays is generally higher, and the average price of disinfectant alcohol is cheaper. If used for hand disinfection and general environmental disinfection, disinfectant alcohol and diluted bleach are cheaper and better choices. The Consumer Council also reminded the public that many people used them to prevent the epidemic. After going out, they may spray their bodies and clothes with disinfectant sprays. However, some disinfectant sprays contain chlorides or other chemicals, which may cause irritation and cause adverse reactions. In addition, long-term and large-scale application of atomised disinfectants in the home environment may also contaminate food and beverages, increasing the risk of accidental ingestion of disinfectants or their residues.