Method Validation for Determination of Benzoic Acid, Salicylic Acid and Sorbic Acid in Vietnamese Pork Sausage by High Performance Liquid Chromatography

Abstract

       Benzoates (Benzoic acid and its salt) and sorbates (sorbic acid and its salt) are allowed to use as preservatives in food according to the Ministry of Public Health (MOPH) Notification No. 281 (2004). Later in 2016, the ministry prescribed the maximum limit (ML) for sorbates in processed comminuted meat products at 1,500 mg/kg and no ML set for benzoates. While salicylic acid is controlled as prohibited substance for food production according to the MOPH Notification No. 391 (2018). To protect consumer, we developed method for determination of these food additives namely benzoic acid, salicylic acid and sorbic acid in pork ball and vietnamese pork sausage. Food additives were extracted from food by ammonium acetate buffer mixed with methanol (60:40) and determined by HPLC under optimum conditions. The method
validation results using vietnamese pork sausage as representative matrix showed that the limit of detection (LOD) and limit of quantitation (LOQ) were 6 and 10 mg/kg, respectively. The linearity of calibration curves of all food additives ranged from 0.5 to 60.0 mg/L and working range was 10 to 1,200 mg/kg with the correlation coefficient (r) were 0.9999. The accuracy was shown as percentages of recovery of benzoic acid, salicylic acid and sorbic acid from spiked sample was 97.06-100.01%, 95.75-100.02% and 98.30-100.29%, respectively. The precision as % of relative standard deviation was in the range of 0.14-0.90, 0.18-0.94 and 0.15-0.83, respectively. The validated method was used to determine these food additives in 84 samples of pork balls and vietnamese pork sausages collected from local markets in Chiang Mai in October 2015 to September 2017. Salicylic acid was not detected in any samples. Benzoic acid was found 78.6% of samples which was considered as substandard food. Sorbic acid was found in 11.9% of samples, the concentration found were lower than the maximum limit. The study suggested that the validated method could be used to survey and examine benzoic acid, salicylic acid and sorbic acid in vietnamese pork sausages.