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The ASTM E1153 is a test method recognized by the EPA for the claim substantiation of sanitizers for use on non-food contact surfaces. For this reason, it is often referred to as the "non-food contact sanitizer" test.
This test is performed by drying bacteria onto glass carriers, treating them with the sanitizer in question, and then neutralizing and enumerating the eluent after a set contact time. The ASTM E1153 has the benefit of being a fully quantitative test, providing the sponsor with percent reduction data and allowing for easy comparisons between different products.
Summary of the ASTM E1153 Test Method
- A microbial culture is prepared, utilizing a number of consecutive daily subcultures prior to initiation of the test culture.
- A volume of microbial culture is placed onto test surfaces to dry. For a GLP test, 5 test carriers and 3 control carriers are typically used.
- In parallel, a number of different "initial bacterial concentration controls" are run, as specified by the method.
- At the end of the contact time, the reaction between microorganisms and the non-food contact sanitizer is quenched using a chemical neutralizer and/or dilution.
- Rigorous chemical neutralization controls are run to ensure that the reaction between the test product and neutralizer are effective.
- After the predetermined contact time, small aliquots of the mixture of bacteria, product, and neutralizer are removed and microorganisms are enumerated using standard techniques.
- Microbial populations on the test surfaces after treatment with the sanitizer are compared with parallel "initial bacterial concentration controls" to determine percent reduction and log reduction.
Strengths of the ASTM E1153 Test
- The impact of a disinfectant product on microorganisms over time (death curve) can be studied with relative ease using this surface-based test method.
- The method is accepted by the EPA when run under GLP test conditions, to support non-food contact sanitization claims.
- Brief contact times can be studied (down to about 15 seconds) with relative ease.
Weaknesses of the ASTM E1153 Test
- Since appreciable volumes of chemical neutralization agents are sometimes required for potent sanitizers, the limit of detection can be somewhat high, compared to other quantitative tests.
- The result to study sponsors is that they cannot necessarily resolve the full percent or log reduction of microorganisms.
- Some of the initial numbers controls (time zero counts) are unnecessary from a scientific perspective.
Microchem Laboratory has run a great number of ASTM E1153 studies under both GLP and non-GLP test conditions. It also makes for a handy "screen" before testing for full disinfection. If your firm is interested in running ASTM E1153 studies, simply contact the lab today!