Green tea is a popular beverage production line which has been consumed in China and Japan for many hundreds of years. Recently, extensive laboratory research and epidemiologic studies have shown that compounds present in green tea (particularly catechins) may reduce the risk of a variety of illnesses. Furthermore, catechins have been shown to suppress accumulation of visceral fat and so may be useful in controlling bodyweight and bodyshape (see, for example, T. Nagao et al., “Tea Catechins Suppress Accumulation of Body Fat in Humans”, J. Oleo. Sci., 2001, 50(9), pp.717-728). These studies, along with the increasing complexity of the consumer's palate have led to growth in the consumption of green tea, even in markets (such as the USA and Western Europe) where there is no tradition of green tea consumption.

Industrial metal detectors help remove metal particles and prevent contamination of a product line. This is especially important if the products are consumed by people or animals. Industrial detectors help ensure water filling machines safety by alerting the presence of unwanted metal (sometimes referred to as "tramp metal") in products. They also can help identify faulty equipment in other production stages. Tramp metal from broken or damaged processing equipment is one source of contamination.

There have been several attempts to provide beverages with enhanced levels of catechins.

European patent EP 0 762 836 B discloses a beverage packaging line whereby cellular hydration and drinkability are enhanced by the combination of green tea solids with selected levels and types of electrolytes and carbohydrates. Unfortunately, however, the presence of significant levels of carbohydrates in the beverage may compromise certain benefits delivered by the catechins. In particular, the high energy contribution of sugars would tend to counteract any benefits of the catechins in terms of controlling bodyweight and/or bodyshape.

European patent application EP 1 297 749 A discloses a beverage having a concentrated or purified tea extract incorporated therein, containing catechins from 0.092 to 0.5 wt. % and quinic acid in a specific weight ratio with respect to the catechins. The beverage is said to have an improved taste and does not cause an unpleasant aftertaste which will otherwise remain after bitterness or astringency peculiar to catechins is alleviated by the addition of a sweetener. However, the beverages disclosed therein require the addition of quinic acid which itself may bring unwanted taste to the beverage. Furthermore, the beverages are still unpleasantly bitter, especially for consumers used to tea-based beverages having relatively low levels of catechins, such as black tea..