CLA content of fermented food products

The CLA content of milk products ranged from 4.6 to 7.1 in Sweden (Jiang, Bjorck, Fond6n, 1997), from 3.6 to 7.0 in the United States (Chin, Liu, Strokson, et al., 1992 Ha, Grimm, Pariza, 1989 Lin et al 1995 Shantha, Deckeer, Ustunol, 1992 Shantha, Ram, O Leary, Hicks, Decker, 1995) and from 4.0 to 11.7 in Germany (Fritsche Steinhart, 1998). The magnitude of the differences in CLA content seems to be smaller for different milk products (Table 4.2) than for unprocessed milk. 

conjugated linoleic acid FAME, fatty acid methyl esters. 

Another possible means of formation of CLA is via enzymatic processes of fermentation. Elevated CLA levels were reported several times in fermented milk products related to raw milk (Aneja Murthy, 1990 Jiang et al., 1997 Shantha, Ram, O Leary, Hicks, Decker, 1995), whereas others found no differences (Boylston Beitz, 2002 Lin et al., 1995 Shantha et al., 1995) in fat basis. However, it seems that commercially nsed dairy starter bacteria have only a minor contribution to the CLA level of the fermented prodnct (Salamon, Ldki, Csapd-Kiss, Csapd, 2009 Sieber et al., 2004), while the nse of snitable strains may lead to favourable results. 

The improvement of the CLA supply of humans can be achieved via CLA-pro-ducing strains. Formation of CLA can be accomplished during the preparation of the food product via dairy cultures, but this process could also be amplified in the human gastrointestinal tract with the administration of probiotics. Recently, a number of 

Kim and Liu (2002) concluded that the CLA production of Lactococcus lactis I-Ol in milk depends on several factors, i.e. substrate (sunflower oil) concentration, pH, incubation time and culture conditions. When sunflower oil was added initially, growing cells produced more CLA than cells in the stationary phase however, stationary cells were capable of producing more CLA when sunflower oil was added shortly before the end of the incubation period. 

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