Taints in Foods

Kilcast [5] provides a brief overview of sensory methods employed in the field overall and then focuses on applying sensory testing to taints and off-flavors. He provides some guidelines for sensory testing that illustrate how this application of sensory differs from traditional sensory testing. His points can be smnmarized as  

When the source of the taint or off-flavor is known, use panelists that are sensitive to the objectionable compounds. He points out that it is difficult to have a sensory panel selected for every potential flavor defect, so one may have to select panelists generally known to be sensitive and reliable. (This is not so different from traditional sensory testing.) 

If a sensory panel cannot be selected that is known to be sensitive to the flavor defect, use a large panel to improve the probability that panelists will be in the group that are sensitive. He suggests a minimum of 15 people (preferably 30) should be used for a triangle test. He cautions that replication is not useful in this type of testing — for if an individual is not sensitive to a flavor defect, testing again does not help. 

Use a high sensitivity sensory test. He suggests using difference tests as opposed to profile-type tests. Difference tests are more rapid and require less training. 

Maximize the amount of information gained from a sensory test. Traditional sensory testing has strict rules about getting a limited amount of information from a given test. Yet it is desirable to use a difference test and then ask for preference information (does the panelist prefer a given sample He or she may like the objectionable sample) and how confident the panelist was in his or her choice. 

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Epoxy is used as a lining for water reservoirs, water mains, and home plumbing systems (Heim and Dietrich, 2007a). These applications can impact sensory quality of tap water in food manufacturing, food service operations, and residential homes. This effect may be most noticeable in water but residual aroma and flavor compounds may cause a taint in foods prepared with these water sources. An odor assessment, using a water industry standard flavor profile analysis method, identified a strong relationship between water (simulated tap water, pH 7.7-7.9) stored in epoxy-lined copper pipes for 3-4 days and an odor described... 

Australian Food and Grocery Council (AFGC). (2007). "Organohalogen Taints in Foods." AFGC, Canberra, Australia. 16pp. (http //www.afgc.org.au). 

Council AFaG. (1997). Organohalogen taints in foods. Food Australia 59(3), S1-S16. 

Land, D. G. (1989). Taints—Causes and prevention. Ch. 2. In "Distilled Beverage Flavour— Recent Developments" (J. R. Piggott and A. Paterson, eds.), Ellis Horwood, Chichester. (In (2007). "Organohalogen Taints in Foods." AFGC, Canberra, Australia. 16pp. http //www.afgc.org.au). 

The potential problem of styrene taint in foods is well known and documented in the literature (Saxby 1996). Styrene (see Chapter 2) is the monomer that is polymerized to make polystyrene (PS) (also known as general purpose or GPPS grade). It is also commonly used with butadiene rubber (5-20 % w/w) as a block copolymer to form high impact polystyrene (HIPS). In addition there are less common copolymer grades such as acrylonitrile-butadiene-styrene (ABS) having a mixture of 25 %, 15-25 % and 50-65 % of each monomer respectively or a copolymer with acrylonitrile (styrene-acrylonitrile, SAN). 

Disinfectants, pesticides, and detergents comprise a group of chemicals that occasionally contribute taints to foods. This may be the result of inadequate care in their application by the end user or errors on the part of the cleaning compound manufacturers. The summary of taints observed at Marks and Spencer (Table 7.3) by Goldenberg and Matheson [4] provides a useful illustration of how these chemicals may enter a food and produce a taint. They noted several incidences of taints in food due to detergent contamination, which are not included in this table. 

Tice, P., Packaging material as a source of taints, in Food Taints and Off-Flavours, M.J. Saxby, Ed., Blackie Acad. Prof., London, 1996, p. 226. 

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