Fish sauce is widely used as a liquid condiment or seasoning, it is made by the fermentation of fish or krill from months to years. Many cultures use fermented fish sauce in cooking, and fish sauce is particularly popular in some parts of Europe, China, Indonesia, Laos, Malaysia, Philippines, Thailand, and Vietnam. The  use of preservatives in fish sauce is thus of growing concern in the Asia Pacific region. Commercial fish sauces might contain different levels of preservatives. Benzoic acid is one of the preservatives commonly found in condiments and beverages for preventing and inhibiting the growth of yeasts and moulds in food. According to the assessment by World Health Organization (WHO), the acute toxicity of benzoic acid is low. However, it is known to cause non-immunological contact reactions (pseudo allergy) in sensitive persons when lower dose of benzoic acid is consumed. For the general population, the main route of exposure to benzoic acid is likely via foodstuffs, which contain the substances naturally or added as antimicrobial agents. Food safety regulations have been set by various jurisdictions for limiting the amount of benzoic acid in sauces, seasonings and condiments. The Codex Alimentarius Commission (CAC) sets maximum levels of food additives in food and feed to protect public health. In the case of benzoic acid, the maximum level in sauces and like products – clear sauces (e.g. fish sauce) is set at 1,000 mg/kg. The European Union has also set maximum levels for preservatives in food, where the maximum level of benzoic acid is set at 1,000 mg/kg in seasonings and condiments.

The purpose of this study was to demonstrate the capability of participating laboratories in measuring benzoic acid in aqueous-based condiments such as fish sauce. The reference value for benzoic acid provided by GLHK will be used as the assigned value for evaluating the performance of the participants in this PT programme. The relevant Calibration and Measurement Capabilities (CMCs) of GLHK on benzoic acid are registered in the BIPM Key Comparison Database (KCDB). The use of reference values traceable to the International System of Units (SI) which allowed more rigorous evaluation of the accuracy of participants’ results. It not only enhanced the quality of the programme but also helped build the measurement capabilities of the participants through a better linkage between the metrology institutes and the analytical laboratories at large.