| Mutton, as one of popular foods in China, has been consumed for a long time, but the main defects of this meat are simple in the structure of product and low in process technology. Fermented sausage is one of meat products fermented mainly with lactic acid bacteria plus other microorganisms. The flavor, aroma and texture of fermented sausage are different from those of other meat products due to the role of the microorganisms in fermentation and ripening. This leads to more microbiological stability in final products, longer shelf-life and better safety than the raw materials does. The purposes of this study were to: (1) produce mutton sausage done with lactic acid bacteria used as meat starters; (2) evaluate the role of the lactic bacterial starters in improving the quality of fermented lamb sausage; (3) establish the optimal technology for processing lamb sausage suitable for Chinese mouth-feel.The fermentation properties of starter cultures used in this study were investigated, including growth in MRS medium at 37℃, their tolerance to different levels of salt and nitrite, and the utilization of protein and fat from lamb meat. It was seen that each strain used went into logarithmic growth at 10 to 14h incubation. Clearly, LAB strains used met a basic demand for selection of meat starter cultures. Among the strains, strains Ros, L.p.A, P.p and Ind-3 had good abilities to tolerate salt with a concentration of 6%, and nitrous acid salt with a concentration of 1.5 x 10-3mg/ kg. They did not have capability metabolizing protein and fat, but were powerful in fermenting sugar to lactic acid. Meanwhile, the four strains were used as starter cultures for the . following studies.Orthogonal design was used to determine the optimal process of lamb sausage fermented individually with the strains Ros, LpA, Pp and Ind-3. The inoculums of 106 cfu/g, 107 cfu/gand 108 cfu/g, sucrose levels of 0.5%, 1% and 2%, and incubation temperatures of 25℃, 30℃ and 37℃ were chosen for producing lamb fermented sausage. The optimum technology was the inoculation of 107cfu/g, 0.5% sucrose, and incubation at 30℃ for strain Rps and Lpa to process lamb sausage. That was inoculation amount of 107cfu/g, sucrose amount of 1%, and fermentation temperature at 30℃ for strains Ind-3 and Pp.The extract of fresh mutton meat used to the simulation of the growth and metabolism of the four strains incubated at 37℃. It was observed that there were quick decline in pH value and acidity due to the presence of the four strains. Protein concentration first increased and thendeclined slightly; the content of amino acid first increased quickly in the beginning and eventually decreased very fast, depending on the strains used. The simulation of growth in lamb extract showed that strain Ind-3 produced the lowest pH than other strains did, but not significant difference in pH was found between strain Ind-3 and strain Pp (P>0.05). A big variation in pH was found between strain Ind-3 and strain L.p.a or strain Ros (P<0.05). The ultimate concentration of protein formed by strain Ros was the most than other strains did (P<0.01). Strain Ind-3 formed the highest level of amino acid, whereas the level of amino acid by strain P.p is lowest (P<0.01). Strain Lpa produced the same amino acids as that of strain Ros.The comparisons of pH, viability of lactic acid bacteria, sensory assay and amino acids were made between the fermented lamb sausage with starter (as tested group) and the natural fermented sausage without any addition of starter (as control).There a big difference in pH value between the tested group and the control samples (P<0.01), depending on the strains used. pH level of fermented sausage was the highest after 24h fermentation in the presence of strain Lpa. Total counts of lactic acid bacteria in tested group were over 10s cfu/g, in comparison with the control containing only 103 cfu/g of lactic bacteria. .If strain Lpa was used as starter culture to ferment lamb meat, fermented lamb sausage produced the best sensory, which was acceptable by most...
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