Natural propionic acid from traditional shrimp pastes from Indonesia

Propionic acid is a food preservative classified as Generally Recognized as Safe (GRAS) and is known to inhibit mold growth. While it can naturally form in foods through bacterial fermentation, limited data on its natural concentrations in fermented foods can cause trade issues. This study emphasized the need for a scientific database on natural propionic acid levels in fermented fish products, referencing a 2021 case where Indonesian fermented fish products were refused due to the presence of propionic acid. Traditional Indonesian shrimp pastes were analyzed using gas chromatography-mass spectrometry (GC–MS), revealing propionic acid concentrations ranging from 1.33 to 24.49 mg/kg, with the highest levels found in Puger and the lowest in Toboali. Molecular analysis confirmed the presence of propionic acid bacteria (PAB), which showed a moderate positive correlation with propionic acid content (r = 0.379, p < 0.05). This research provides the first dataset on natural propionic acid content in shrimp pastes, offering a scientific foundation for future regulatory and trade policy development.