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Pure N(2) gas was introduced in the headspace of test bottles containing raw milk that were then stored at either 6.0, 7.0, or 12.0 degrees C. Treatment with N(2) significantly reduced the growth of total bacteria, and the growth of bacterial subgroups such as psychrotrophs, enterobacteria, protease- and lipase-producing bacteria, and Listeria spp, and completely excluded Bacillus cereus growth on MYP plates. The inhibitory effect was maximal at 6.0 degrees C, and bacterial growth could be halted at this temperature for 11 days. At 12.0 degrees C, N(2) was able to inhibit growth during the first 48 h. No alarming or undesirable effects, such as the excessive growth of anaerobes or lactobacilli, were observed during the course of the study. The same treatments also halted the growth of one bacterial isolate in pure culture that expressed multiresistance to antibiotics. The continuous flushing of raw milk with pure N(2) gas in a so-called open system that allows gas exchanges with the environment positively impacted the microbiological quality of the raw milk at a temperature range of 6.0-12.0 degrees C. This procedure should therefore be considered as a possible complementary method to refrigeration in controlling bacterial growth and the spoilage potential of both psychrotrophs and mesophiles in raw milk.

As a fermented product, tarhana is the dry form of yogurt-cereal mixture and represents an important part of the diets of many people in different countries including Turkey. In the present study, the effects of the addition of baker's yeast on the quality and functional properties of tarhana were investigated. Tarhana was produced under laboratory conditions (uncontrolled and controlled conditions) using two formulas. Some physicochemical, functional, and sensory properties of the samples were analysed. An increase was found in the acidity value of all samples during the fermentation period. The addition of baker's yeast affected the functional properties (water absorption capacity, foaming capacity, foaming stability, emulsifying activity) of the samples (P < 0.05). The tarhana samples produced by the addition of yeast and under controlled conditions had shorter fermentation times and better sensory properties. This research suggests that the addition of baker's yeast and the employment of controlled conditions can be recommended in the production of the commercial type of tarhana.

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