Determination of naturally derived propionic, benzoic, and sorbic acids in seafood, meats, and fruits during storage

Propionic acid, benzoic acid, and sorbic acid are common preservatives in processed foods, but their natural concentrations in raw foods are not well understood. In Korea, if propionic acid or benzoic acid exceeds certain levels in processed plant-based foods, manufacturers must prove they are naturally occurring to avoid recalls. This regulation applies to both local and imported products, with non-compliance leading to economic costs and damage to brand reputation. To address this, further research is needed to build a database of naturally occurring preservatives in raw foods and develop food safety standards. This study quantified the levels of propionic, benzoic, and sorbic acids in 37 raw foods stored at different temperatures for 2 weeks, using gas chromatography and high-performance liquid chromatography. The changes in acid concentrations during storage were examined, with preservatives identified by mass spectrometry. Sensory evaluation and total viable count were used to assess spoilage in seafood and meat samples. The matrix effects were evaluated, and the quantification methods were validated using seven food matrices. The intra- and interday accuracies and precisions (% relative standard deviation, %RSD) values met the Codex guidelines. In general, the propionic acid contents of most seafood and meat samples increased during storage, with the highest content being found in manila clams. Interestingly, the fresh sea squirt sample contained a higher propionic acid content (456 mg/kg) than the other samples. However, benzoic acid and sorbic acid were not detected in most samples, with the exception of the jujube and apple samples. • Propionic, benzoic, and sorbic acid preservatives can arise naturally in foods. • Changes in the preservatives and/or microbial counts in 37 raw foods were determined. • The propionic acid levels increased in most seafood and meat samples during storage. • Based on sensory data, the contents in the edible state were evaluated. • Benzoic and sorbic acids were only detected in jujubes and apples.