Assessment of benzoic acid levels in milk in China

Abstract

Benzoic acid is the most commonly used preservative in foodstuffs. Although benzoic acid is generally recognized as safe (GRAS), adverse effects such as asthma, urticaria, metabolic acidosis and convulsions were observed at low doses in sensitive persons. Some weak clastogenic activity was noted in in vitro assays. The aim of our study was to determine the levels of benzoic acid in milk samples consumed in the city of Guangzhou, China. In this study, 142 samples of pasteurized milk (24), ultra high temperature milk (UHT, n = 45), milk powder ( n = 31) and infant formula ( n = 42) were analyzed by high performance liquid chromatograph (HPLC) with diode array detector (DAD) from October 2006 to January 2007. Benzoic acid was detected in 109 (76.8%) samples, ranging from 0.51 to 111 mg/kg. The LOD for benzoic acid was, respectively, 0.2 mg/kg in pasteurized and UHT milk, 2 mg/kg in milk powder and infant formula. The mean recoveries of spiked samples at 4 levels were 99.5 ± 3.1% in liquid milk, and 98.5 ± 4.3% in milk powder, respectively. The results show that benzoic acid widely occurs in milk and milk products in China at the low levels. The levels found are not high, and should not affect the general public; however, it may affect the infants and/or sensitive persons. Therefore, it is important to assess the levels of benzoic acid in milk in China. Meanwhile, it should be noted that the lowest percentage of positive samples in pasteurized milk probably results from the difference in the quality of raw milk, processing technical and storage condition of milk products.