1. Principle1. Principle

1. Principle

The method, as applied to Hospital Grade Disinfectants or Sanitisers, is essentially that given by Kelsey & Maurer (1) for testing disinfectant performance. It is set out in a form suitable for attachment to a regulatory minimum standard for disinfectants and antiseptics. For wider application of the test refer to supplementary note A.
The disinfectant is tested at the dilution recommended by the manufacturer on the product label. The test consists of challenging the diluted disinfectant with bacterial inoculum, withdrawing a sample after a given time and culturing the sample in a suitable recovery medium. After this sampling, the mixture is again challenged by a second inoculum and after a second interval is again sampled for culturing. The sample is passed or failed according to the extent of growth shown in the two cultures sampled. The test may be performed with or without the addition of sterile yeast as an organic soil. (Options B and A respectively) or both, according to the use‑situations advocated on the label of the product under test.
Table 1. Selection of test parameters for classes of disinfectant and antiseptic using the TGA Disinfectant Test.

<table cellspacing="0" cellpadding="0" style="border:1pt solid #000000; border-collapse:collapse"><tbody><tr><td style="width:76.3pt; border-right:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:10.05pt"><span></span></p><p><span>Class of product</span></p></td><td style="width:76.3pt; border-right:1pt solid #000000; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:10.05pt"><span></span></p><p><span>Organisms used in the test</span></p></td><td style="width:76.3pt; border-right:1pt solid #000000; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:10.05pt"><span></span></p><p><span>Test option for resuspension of centrifuged organisms</span></p></td><td style="width:76.3pt; border-right:1pt solid #000000; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:10.05pt"><span></span></p><p><span>Number of challenges</span></p></td><td style="width:76.3pt; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:10.05pt"><span></span></p><p><span>Inoculum density</span></p></td></tr><tr><td rowspan="2" style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>Disinfectant </span><span>‑</span><span> hospital grade: Sanitiser</span></p></td><td rowspan="2" style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span style="font-style:italic">Ps. aeruginosa</span></p><p><span style="font-style:italic">Pr. vulgaris</span></p><p><span style="font-style:italic">E. coli</span></p><p><span style="font-style:italic">S. aureus</span></p></td><td style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>A</span><span> </span><span>(</span><span>“</span><span>clean</span><span>”</span><span> </span><span>conditions)</span></p></td><td rowspan="2" style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span></span></p><p><span>2</span></p><p><span></span></p></td><td rowspan="2" style="width:76.3pt; border-top:1pt solid #000000; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span></span></p><p><span>2x10</span><span style="font-size:8pt; vertical-align:super">8</span><span> </span><span>‑</span><span> 2x10</span><span style="font-size:8pt; vertical-align:super">9</span></p></td></tr><tr><td style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>B</span><span> </span><span>(</span><span>“</span><span>dirty</span><span>”</span><span> </span><span>conditions</span><span>”</span><span>)</span></p></td></tr><tr><td style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>Disinfectant </span><span>‑</span><span> household or commercial grade</span></p></td><td style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span style="font-style:italic">E. coli</span></p><p><span style="font-style:italic">S. aureus</span></p></td><td style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>C</span></p></td><td style="width:76.3pt; border:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>1</span></p></td><td style="width:76.3pt; border-top:1pt solid #000000; border-left:1pt solid #000000; border-bottom:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span>2x10</span><span style="font-size:8pt; vertical-align:super">8</span><span> </span><span>‑</span><span> 2x10</span><span style="font-size:8pt; vertical-align:super">9</span></p></td></tr><tr><td style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p style="margin-bottom:2.9pt"><span>Antiseptic (excluding those for intact skin only)</span></p></td><td style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; border-left:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p><span style="font-style:italic">Ps. aeruginosa</span></p><p><span style="font-style:italic">Pr. vulgaris</span></p><p><span style="font-style:italic">E. coli</span></p><p style="margin-bottom:2.9pt"><span style="font-style:italic">S. aureus</span></p></td><td style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; border-left:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p style="margin-bottom:2.9pt"><span>D</span></p></td><td style="width:76.3pt; border-top:1pt solid #000000; border-right:1pt solid #000000; border-left:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p style="margin-bottom:2.9pt"><span>1</span></p></td><td style="width:76.3pt; border-top:1pt solid #000000; border-left:1pt solid #000000; padding-right:6.45pt; padding-left:6.45pt; vertical-align:top"><p style="line-height:8.15pt"><span></span></p><p style="margin-bottom:2.9pt"><span>1x10</span><span style="font-size:8pt; vertical-align:super">6</span><span> </span><span>‑</span><span> </span><span>1x10</span><span style="font-size:8pt; vertical-align:super">7</span></p></td></tr></tbody></table>