Semi industrial production of Tsalafouti dairy product

Tsalafouti is a fermented dairy product produced from 'boiled', naturally acidified sheep milk during summer (end of lactation period) as a farmhouse product. As consumer's demand is regular throughout the year, a semi-industrial production method of Tsalafouti was investigated based on the artisanal processing method aided with the use of a commercial multi-strain Lactococcus lactis starter culture for optimal milk acidification. Main physicochemical and microbiological characteristics, level of proteolysis and volatile compounds of the new product were determined. The semi-industrial Tsalafouti had smooth firm texture, mild sour taste, pleasant aroma, and received high panel-sensory scores up to day 45 of storage; afterward, the product developed an unpleasant flavor. The ripened (day 30) product had pH 4.28, moisture 81.5%, fat 6%, fat-in-dry matter 32.53%, salt 0.33% and proteins 5.49%, and contained high levels of heptanal, acetone, hexanal and 3-methyl butanal. The Lc. lactis starter (4 strain biotypes) grew abundantly (>9 log CFU/g) and acidified the milk within the first 10 days of ripening at 10 ℃. Viable starter cell populations declined significantly during late ripening and storage, probably due to autolysis. No growth of thermophilic streptococci, mesophilic non-starter lactobacilli or leuconostoc-like bacteria, enterococci, staphylococci, coliform bacteria and yeasts occurred during ripening. Only spoilage molds grew on the product surface after 45 to 60 days of aerobic storage at 2-4 ℃. The present data may contribute to the industrial production of Tsalafouti, giving an added value to this traditional Greek dairy product.