Rubber and chemical migration into food

In contrast to plastics, rubbers are rarely used in the packaging of food products. Exceptions to this rule are the use of rubber in flip top seals on beer bottles and the seal that is present in food cans. However, in the processing of food, there are a number of situations where significant contact with rubber products can occur. This is due to the fact that the unique properties of rubber lead to it being used in a wide range of products (see Table 12.1). It is also the case that the range of contact conditions encountered (i.e. food type, contact temperature, time and area) mean that a wide variety of rubber compounds are employed (see section 12.2). 

Variations in contact conditions have an important effect on the potential of chemical species to migrate from the rubber components into the foodstuff. 

In general, the use of rubbers for mainly processing applications means that the contact times with food are short (e.g. minutes) and the contact areas, apart from hose and belting, are small. This is in contrast to plastics which, when used as packaging materials, often have long contact times (e.g. weeks) and relatively large contact areas. 

The objective of this chapter is to provide a comprehensive overview of the use of rubber as a food contact material, from an initial description of the types of rubber and rubber products that are used in the industry, through the formulation of products, and the contact regulations and migration testing regimes, to the research that is on-going to improve its safety and the trends for the future. 

2 Rubber materials and products used in contact with food 

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Rubber and chemical migration into food 289 12.5.5 Published migration data... 

All of the rubber compounds tested were found to contain chemical species that have the potential to migrate into food. Whether these migrating species are of concern will depend on the time, temperature, surface area of rubber that is in contact with them, and the fat content of the food (Table 8.1). 

Butylated hydroxytoluene (BHT) is an antioxidant commonly utilized as an additive in food and in rubber and plastic products. Its chemical migration from plastic packaging into the package s content has been shown [82]. A method for the determination of BHT in bottled water by means of SPME-GC-MS was developed [83]. The method was also appUed to evaluate the presence of BHT in mineral and mineralized bottled drinking water and it appeared in seven out of fifteen samples studied. The maximum observed concentration was 38 p.g L. All studied plastic bottles were made of PET. The PDMS fiber was exposed to 15 mL aliquots for 30 minutes at ambient temperature and under magnetic stirring. Relative standard deviation was 4.3% and the limit of detection was 4.2 pg L ... 

Certain chemical components of plastic food packages or rubber parts that are contacting with food can migrate and transfer into the latter, and can became a component of the food [1]. 

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