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 degrees C. 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 degrees C. The present data may contribute to the industrial production of Tsalafouti, giving an added value to this traditional Greek dairy product.