Bromophenol formation as a potential cause of `disinfectantʹ taint in foods

A potential cause of `disinfectantʹ taints in foods is the formation of bromophenols as a result of reactions between brominating agents (residual or nascent) and phenol (food-derived or contaminating). This was studied using simple model systems containing either elemental bromine or bromochlorodimethylhydantoin (BCDMH) and phenol. Bromophenols were quantified by adding an internal standard to the model system and then analysing the compounds by solid phase micro-extraction and GC–MS. Low levels of bromophenols were generally formed in bromine mixtures, though this depended on the presence of citrate buffer and on storage of the bromine in the buffer prior to reaction with phenol. The individual bromophenol isomers were often present in considerably greater amounts than the published taste threshold levels. This was particularly evident for 2-mono- and 2,6-dibromophenol which were therefore the most likely causes of the `disinfectantʹ aroma in the simple models. The BCDMH reaction with phenol led to the same bromophenol isomers as in the elemental bromine reaction. Although bromophenol levels were lower, the taste thresholds for the 2-mono-and 2,6-dibromophenol were again significantly exceeded. The relevance of these observations for taint formation in foods is discussed.