Rapid method to determine natamycin by HPLC-DAD in food samples for compliance with EU food legislation

- A screening method that allows detect natamycin at the regulatory level is reported.
- A survey on the presence of natamycin in different foods is performed.
- LC-MS/MS (ESI) in positive mode was used to confirm the results.

Natamycin is an antibiotic belonging to the group of polyene macrolides extensively employed as additive to prevent the microbial deterioration in food. The Annex III of the Directive 95/2/EC fixes in 1 mg/dm2 the maximum level of the antifungal allowed in the final product.Reliable and sensitive methods for the analysis of natamycin are required to guarantee compliance with food legislation as well as to improve consumer protection.In the present paper, a simple and rapid high performance liquid chromatographic method with diode-array detection (HPLC-DAD) to determine natamycin in food samples was developed. Natamycin was extracted from food samples by using methanol acidified with acetic acid. The chromatographic separation was performed on a reversed-phase Kromasil ODS (C18) (150 × 3.20 mm i.d., 5 μm particle size) and the analysis was completed within 6 min. The method was validated in terms of linearity, limits of detection and quantification, repeatability and recovery. Satisfactory repeatability (R.S.D. (n = 10) < 4%, excellent sensitivity (LOD: 0.01 μg/mL; LOQ: 0.05 μg/mL) and appropriate recoveries were achieved.With the proposed method natamycin levels were determined in different food items. Data showed that two samples exceeded the limit established by the Annex III of the Directive 95/2/EC. Natamycin was also detected in samples in which its use is not allowed. The results were confirmed by LC-MS/MS using electrospray ionization (ESI) in positive mode.