Foodstuffs contamination

G Martens, H Bomsdorf, G Harding, J Kanzenbach and R Linde (1993) Coherent scatter x-ray imaging for foodstuff contaminant detection. SPIE 2092, 387-398. 

The level of As is very low in most foods. The exception is seafood, for example, plaice, which often has an As concentration of >10 mg kg-1. As mentioned above, FAAS is not the first choice for this kind of determination. Dry ashing in combination with HG-AAS is well suited for this purpose and has sufficient detection power for the analysis of concentrations well below 0.05 mg kg-1, levels that can be found in pork and beef. ET-AAS after MW digestion is also suitable for seafood, but lacks the detection power necessary for the analysis of other foodstuffs. Contaminated chemicals can be a problem, and it is advisable to have new batches checked before use. 

The upshot is that the standard that is set is very cautious because of the safety factors used, especially if safety factors of 1,000 or higher are used. Moreover, the adverse effects observed in animals usually result from continuous repeated exposure and not single doses, which is clearly different from occasional exposure as a result of eating a foodstuff contaminated with a chemical. 

Cyclic imines are, however, toxic to experimental animals, and the possibility of harmful effects in humans who consume foodstuffs contaminated with these substances must therefore be evaluated. 

Cyclic voltammetry is not primarily a quantitative analytical technique. The references at the end of this chapter provide additional guidance to its applications and interpretation. Its real value lies in the ability to establish the nature of the electron transfer reactions—for example, fast and reversible at one extreme, slow and irreversible at the other—and to explore the subsequent reactivity of unstable products formed by the forward sweep. Suffice it to say that such studies are valuable for learning the fate and degradation of such compounds as drugs, insecticides, herbicides, foodstuff contaminants or additives, and pollutants. 

On 30 May a Council Regulation laid down restrictions on the specific activity of milk, cheese and other foodstuffs imported into the Community, of 370 Bq/kg for milk, rising to 600 Bq/kg for cheese and other foodstuffs. This regulation was intended to deal specifically with foodstuff contamination by Cs-134 and Cs-137 and was stricter than recommendations to the European Commission by a Group of Experts set up under the provisions of the Euratom Treaty (the Article 31 Group ) (see Table 8.3). This was because the Council felt it should harmonise its regulations with those of countries outside the Community such as the USA, which had set similar limits. By agreement, member states accepted that trade in foodstuffs within the Community would abide by the same levels and that no state would set lower national levels. 

In addition to spice-processing plants, spices are handled in almost all places where food is prepared or meals are served. Of the five patients with occupational spice allergy reported by Kanerva and his coworkers, two were chefs, one a kitchen assistant, one a coffee-room assistant and one a self-employed restaurant worker (Kanerva et al. 1996). Spices may be handled directly, but workers may also be exposed indirectly to spiced foodstuffs, contaminated spice containers and contaminated work surfaces. The exposure may be aerogenic when bare and wet hands are used to add powdered spices to foods. 

Threat category V is for areas that are far enough away from category I or II facilities not to require implementation of urgent proteetive actions such as evacuation, relocation, and sheltering but where there is a potential for food and foodstuff contamination that calls for the implementation of agrieultural countermeasures and foodstuff monitoring and control. 

Low pressure polyethylene might contain minute traces of oxygen or nitrogen or sulfur chain transfer catalyst residues. These are usually labile and can be ignored from the foodstuff contamination point of view. Polymers such as polyethylene, polypropylene and polystyrene manufactured by a catalysed low pressure route will however, usually contain appreciable catalyst residues usually appearing in the form of aluminium, chromium, magnesium and titanium, also possibly lithium and sodium. As the example quoted in Table 3.1 indicates these impurities can occur in the polymer at levels approaching 100 ppm. 

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