disinfectant tests

Disinfectant tests

The EN methods themselves are of value as a means of determining the efficacy of a disinfectant under controlled conditions.

The EN methods below are designed to evaluate the bactericidal, fungicidal, yeasticidal, basic sporicidal or mycobactericidal activity of a product used under various conditions. Many methods are suspension based and are used to support general antimicrobial claims while other test methods are carrier-based and are used to support antimicrobial activity of products on surfaces or devices. In either case, the same general principles apply.

The test organism is exposed to sample of the product in a manner which simulates the desired claim. Following exposure, the test system is neutralized and quantitatively assayed for survivors. The resulting plates are incubated, enumerated, and a reduction in viability or microbiocidal effect is determined as compared to a population control.

Type of organism tested, test temperature and contact time may be varied but still utilising the EN protocols.

 

EN1276

Quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics used in food, domestic, and institutional areas. This will test the product when diluted in hard water, against clean and dirty conditions at 20°C for a 5-minute contact time.

The product should demonstrate at least a 5-log reduction (99.999% kill) in viable counts. Other temperatures and contact times can be used once the product has been shown to meet the requirements. The micro-organisms used are Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and Enterococcus hirae. Other micro-organisms can be added (such as Listeria monocytogenes and Salmonella Typhimurium).

 

EN1650

Quantitative suspension test for the evaluation of fungicidal activity of chemical disinfectants and antiseptics used in food, domestic, and institutional areas. This will test the product when diluted in hard water, against clean and dirty conditions at 20°C for a 15-minute contact time.

The product should demonstrate at least a 4-log reduction (99.99% kill) in viable counts. Other temperatures and contact times can be used once the product has been shown to meet the requirements.  The strains used are Candida albicans and Aspergillus niger.

 

EN13697

In EN13697, the test organisms are dried onto a surface, and then covered with the test disinfectant.

The method is applicable to bacteria where the test organisms are Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Enterococcus hirae. A log 4 reduction in population is required in 5 minutes.

EN13697 can also be used for yeast and fungi, where the test organisms are Candida albicans and Aspergillus niger. A log 3 reduction in population is required in 15 minutes.

Test temperatures for EN13697 are usually 20°C in hard water under either clean or dirty conditions. As with EN1276 and EN1650 additional organisms can be added to the test.

 

EN13704

Quantitative suspension test for the evaluation of sporicidal activity of chemical disinfectants used in food, industrial, domestic and institutional areas.  

 

EN 14476

Quantitative suspension test for the evaluation of virucidal activity.  Claims can be made for full virucidal activity if the disinfectant is tested against the Polio and Adeno viruses, whilst partial virucidal activity claims can be made if tested against murine norovirus.

 

BS5929: Part 3

This test establishes whether the product will or will not cause tainting of food if left on a food contact surface at its recommended concentration. Referred to as the ‘Triangular Test’ method it essentially involves spraying a stainless steel plate with a 2% solution of the disinfectant (twice the recommended strength) and allowing to dry overnight.

The plate is then placed in contact with a high fat material such as butter, stored at ambient temperature (16-18°C) for 24 hours and then chilled for 1 hour before testing. Assessors will then taste various samples of the butter, some of which have come into contact with the disinfectant and some not, before commenting.

Once the product has passed the test then the standard will be awarded. Note: high fat material is used as the example food stuff because these are the most likely to absorb taint components of a disinfectant, they are therefore useful models.