Free salicylic acid and acetyl salicylic acid content of foods using gas chromatography–mass spectrometry

Dietary salicylates inhibit cycloxygenase-2 and may therefore have anti-inflammatory properties similar to those of aspirin. Individuals that are sensitive to aspirin may also be intolerant to non-acetylated salicylates and could benefit from a low salicylate diet. A total of 76 foodstuffs comprising fruit (16), fresh and prepared vegetables (13), herbs and spices (12), flavourings and sauces (9), beverages (20) and miscellaneous foods (6) were analysed using gas chromatography with mass spectrometric detection and ¹³C carboxyl SA as internal standard. Thirty-seven of the samples contained detectable SA, the highest levels being found in dried herbs (up to 28.6 mg/kg), whereas only one sample (curry sauce) contained detectable ASA at 0.34 mg/kg. Limits of detection for both SA and ASA were matrix-dependent and ranged from 0.008 to 0.23 mg/kg. The results show many inconsistencies with previous data and highlight the need for analysis of a wider range of foods and drinks that are currently available.