Chemical tainting of foods

Abstract

Taints and off‐flavours in food are a major cause of consumer rejection of the food product, and consequently the occurrence of such flavour defects is of great concern also to the manufacturer. Unacceptable flavours in foods may develop within the food through chemical or microbial action on food components, or they may be inadvertently introduced into the food during processing or storage, by absorption of chemicals from airborne, waterborne or packaging‐related sources. The chemicals responsible for taints and off‐flavours are usually volatile organic compounds, which are frequently found at concentrations of less than 1 μg kg−1, and cause flavour problems because of their low odour‐threshold values. This paper discusses the possible origins of off‐flavours and taints in foods, and describes some incidents in which food taints have been caused by chemical contamination from the environment.

Analysis of food taints and off-flavours: a review

“…Some common taints associated with these sources are discussed in this section and summarised (Table 2), although it should be noted that the list is not exhaustive as changes in practices and developments in processes can lead to previously unknown taints being formed. Mottram (1998) described the origins of some chemicals responsible for taints and off-flavours in foods and gives details of several specific incidents. Examples of the causes of taints investigated in our own laboratories concluded that 'musty' tea was due to the presence of tribromoanisole; a soapy taint in soup was from decanoic and octanoic acids; disinfectant taints in soft drinks and instant soup powder from di-and tri-chlorophenols and in fish sticks were due to chlorocresol, all of which were a direct result of cross contamination during processing or storage.…”

“…UV-cured inks and varnishes are essentially solvent-less, but residual acrylate monomers, photoinitiators (Sagratini et al, 2008), such as benzophenone, or reaction by-products from the polymerisation process, such as benzaldehyde and alkyl benzoates, can lead to trace odours, that could migrate into the food product. Mesityl oxide ( 4-methylpent-3-en-2-one), previously used as a solvent for paints and lacquer coatings, can react with hydrogen sulphide (present naturally in many foods) to form 4-mercapto-4-methylpentan-2-one, known to produce a catty odour (Mottram, 1998).…”

“…Methyl ketones present in the majority of foods at low concentrations can react to form chloroform or iodoform. These reactions can depend on the presence of other compounds, for example sequestering agents for metals can be added to decrease metal-catalysed formation reactions, whereas the presence of quaternary ammonium compounds can increase reactions (Olieman, (Mottram, 1998). If chlorine-based disinfectants are used on the same site as phenolic disinfectants then a reaction can occur -not only in the drain but also potentially in the atmosphere.…”

“…However, this distinction is seldom made, particularly in consumer complaints, as both can be picked up by odour or taste and give the impression of poor food quality. Previous reviews on food taints have discussed the origins of food taints in detail (Mottram 1998;Whitfield 1998), but this review also considers the analytical approach to the determination of both known and unknown tainting compounds and includes methods introduced in recent years for taint analysis.…”

An alternative method for analysis of food taints using stir bar sorptive extraction

“…The origins of taints and off-flavours have been reviewed [1,2] and more recently the methods of analysis used for determination of tainting compounds in foods [3]. Current extraction methods for taint analysis fall into two categories.…”