Performance Characteristics of the Quantitative Method for Staphylococcus aureus in Food Products Correspond to ISO 16140-3: 2021

Staphylococcus aureus is a pathogenic bacterium that poses significant health risks when present in food products. High levels of Staphylococcus aureus in food can indicate poor hygiene and handling practices during food production, processing, or storage. In order to maintain food safety and quality, verification of the quantitative method of Staphylococcus aureus is very important. Method verification represents a crucial stage in guaranteeing that all employed procedures conform to the necessary criteria for dependable and precise data. Following the guidelines established in ISO 16140-3:2021, method verification is accomplished through the calculation of the Intralaboratory Reproducibility Standard Deviation (SIR) for implementation validation and the eBias value for verifying the suitability of the method for assessing specific food items. This research was conducted with the objective of confirming the ISO 6888-1:2021 as the designated reference method for quantifying Staphylococcus aureus in food products. For the purpose of confirming the implementation of the method, Cheese was utilized as the test food item. In the context of verifying the method's applicability to different food products, a range of items including condensed milk, margarine, baby porridge, cassava chips and ready-to-eat sausage were examined as challenging foods. Every chosen food item was artificially contaminated with Staphylococcus aureus WDCM 00034. The SIR value obtained was 0.04 ≤ 2× 0.11 (the lowest mean of SR value from ISO 6888-1:2021) which indicated that the National Quality Control Laboratory of Drug and Food (NQCLDF), Indonesian FDA was able to implement the method very well. In addition, the eBias value for all types of food tested was below 0.5log10, which showed that the quantitative method for coagulase-positive Staphylococci (Staphylococcus aureus and other types) could be applied in the NQCLDF laboratory for the extensive scope of food.