A simple and fast method for the inspection of preservatives in cheeses and cream by liquid chromatography- electrospray tandem mass spectrometry

• There is a lack of analytical data regarding preservatives in Brazilian dairy products.
• A simple extraction, fast method for the control of preservatives was developed.
• Due to the matrix effects, we applied a validation for each matrix.
• The method applicability was checked in several cheese and cream samples.
• A surprising rate of unconformities was revealed.

In this work, a simplified extraction and short time of analysis method for the simultaneous determination of natamycin, nisin and sorbic acid in cheeses and cream by reverse phase liquid chromatography-electrospray-tandem mass spectrometry was developed. Full validation was performed according to the Commission Decision 2002/657/EC criteria and method applicability was checked on several samples, aiming to inspect their compliance with regulatory limits. The method was linear in the concentration ranges of 0–10 mg kg−1 (natamycin), 0–25 mg kg−1 (nisin) and 0 20 mg kg−1 (sorbic acid). Samples of the three most consumed types of cheese (fresh, pasta filata and ripened) in Brazil and cream (ultra high temperature and pasteurized, 20–30% fat content) were assessed. A surprising rate of non-compliance was observed, especially among ripened grated cheeses, since 80% of samples were above the maximum limit for sorbic acid with an average concentration of 2766.3±10.8 mg kg−1. Moreover, a major non-compliance for the cream samples was observed. The proposed method can be applied as an efficient tool for the inspection of preservatives in cheeses and cream.

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