Endogenous level of acetic acid in yellowfin tuna (Thunnus albacares): a pilot study about a possible controversy on its residue nature

ABSTRACT

A method based on headspace solid-phase microextraction (HS-SPME) followed by GC-MS analysis was developed for the determination of underivatised acetic acid in fresh tuna fish muscle. Parameters such as the fibre selected and the extraction time and temperature were optimised and the linearity, detection limits and precision of the whole analytical procedure were assessed. The method was then applied to determine the acetic acid concentration in fresh yellowfin tuna muscles (Thunnus albacares) in order to evaluate the endogenous level and its variations during the shelf life under different storage conditions. A qualitative comparison was also made with variations in histamine levels to evaluate the possibility of the joint monitoring of acetic acid and histamine to identify fish stored in poor conditions. The caudal area always had a lower content of acetic acid than the ventral area, independent of the storage time and temperature. A difference was found between the 6- and 3-day time points and day 0 at a storage temperature of 8°C and between the 6-day time point and day 0 at a storage temperature of 0°C, independent of the anatomical area of the sampled tissue. The evaluation of acetic acid could represent an important approach in the field of food safety to detect the illicit use of acetic acid as an antibacterial preservative treatment or to eliminate the unpleasant smell of trimethylamine.

GRAPHICAL ABSTRACT

KEYWORDS:

• Acetic acid
• yellowfin tuna
• solid-phase microextraction (SPME)
• GC-MS
• histamine
• food safety

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was funded by the following large retailers: Auchan Retail Italia, Fiorital S.p.A., Il Gigante (Dr Pessina Davide), Conad, Carrefour Italia and Bennet S.p.A. through the project ‘Evaluation of Acetic Acid Natural Level in Yellowfin Tuna’, supported by Fish Market of Milan, which provided and sampled all tuna used in the present study, and by the Lombardy Region Institution – Veterinary prevention O.U. – Dr Piero Frazzi and Dr Stefano Foschini.