Recent analyses using solid phase microextraction in industries related to food made into or from liquids

Solid Phase Microextraction (SPME) is an evolving technique invented in the early 1990's. This review discusses SPME use in the food processing industry, in particular industries that produce their products in liquid form: the milk industry, wine industry, and from processors that use fruits and vegetables to produce juices. Milk and its associated products and wastes were examined with an emphasis on how to overcome the difficult and complex matrices that milk, cheese and whey present for SPME analyses. Despite this, compounds such as aldehydes have been detected in dairy products at only 12 ng/g. Wine is a simpler matrix for SPME analyses with a range of compounds detected from 0.2 μg/L for pesticides up to 5701 mg/L for furans. SPME analyses of fruit and vegetable also detected a range of different compounds with a range from 2 pg/g for pyrazines in grapes all the way up to 1762 mg/L for terpenes in citrus fruits. A study of canned foodstuff that encompassed over 100 different foods found furans at just 0.003 ng/g using SPME technology. The review describes the typical classes of compound found in food products including volatile and semi-volatile aromas, taste molecules, degradation products and contaminants. For all three industries there were similar analytes, whether due to the same input, biosynthetic pathways or contaminants.