Temperature processes, cold storage

Fractionation or winterization is a process in which the more saturated molecular species in the oil are solidified during low temperature treatment and subsequently removed cold storage stability is thereby increased. When partially hydrogenated soybean oil is fractionated, the more saturated molecular species are removed to produce a clear oil that meets the requirements of a salad oil and a high-stability liquid oil. 

Jensenin P is a bacteriocin produced by P. jensenii B1264- which inhibits closely related propionibacteria and lactic acid bacteria. It was shown that jensenin P is a new anionic bacteriocin (Ratnam et al., 1998). Jensenin P is stable at lOOT for 45 min, at pH 2 to 10 for 225 min, and in 0.1 to 0.3M NaCl (pH 10) for 225 min (Barefoot et al., 1995). The resistance of jensenins to the extremes of pH and high temperature, their wide inhibitory spectrum allows to consider them as useful natural preservatives in thermal food processing. P. jensenii strain DFl was found (Miesher et al., 1998) to markedly inhibit other P. jensenii strains and to suppress 15 out of 24 yeasts and 3 out of 4 molds tested. From the culture broth of P. jensenii DFl an inhibitory protein substance, named SMI, was isolated and partially purified (Miesher et al., 1998). Crude propionicin SMI was sensitive to proteolytic enzymes and stable to incubation at 30°C (more than 14 days), cold storage (more than 6 months at 4 C) and heat treatment (15 min, 100 C). 

Other processes (except milk drying) require the finished product to be cooled to a suitable storage temperature, usually 4°C or thereabouts, and kept cool until the point of sale. Conventional-type cold stores can be used for mixed dairy products, since all of them will be packaged and sealed after manufacture. 

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