Validasi dan verifikasi metode analisis bakteri asam laktat pada produk susu

Abstract

Lactic acid bacteria (LAB) is a group of bacteria that capable converting carbohydrates (glucose) into lactic acid and mostly grow at facultatif anaerobic condition. At present, the most widely method used to enumerate LAB in some laboratory in Indonesia is incubation in aerob condition. In order to ensure that the method has a good performance, there is a need of method validation. Validation is the confirmation by examination and provision of objective evidence that particular requirements for specified intended use are fulfilled. The purpose of this study is to validate the quantitative method for enumeration of lactic acid bacteria. Two methods of enumeration of LAB in yoghurt were studied, i.e. ISO 7889-2003(E) as a reference method and SNI 2981-2009 as an alternative method. The principle of this method is to grow the facultative anaerobic bacteria in aerobic and anaerobic condition incubated for 3 days at 37 oC on MRSA media. The anaerobic condition was made using Anaxomat jar whose enrich with 10% CO2. The result obtained by these two method were compared. Therefore several parameters such as precision (RSD), relative accuracy, linearity, limit of detection, and limit of quantification were evaluated. The results showed that RSD of these methods between 0.44% and 3.03%, percent recovery of these methods between 97% and 101%, and limit of detection are 3 cfu/mL. It can be concluded that these two methods have good performance characteristics.