Journal of Dairy Science
A novel slow-growing, obligatory heterofermentative, nonstarter lactic acid bacterium (NSLAB) Lactobacillus wasatchensis WDC04 was studied for growth and gas production in Cheddar-style cheese made using Streptococcus thermophilus as the starter culture. Cheesemaking trials were conducted using St. thermophilus alone or in combination with Lb. wasatchensis deliberately added to cheese milk at a level of ~104 cfu/ml. Resulting cheeses were ripened at 6 or 12°C. At d 1, starter streptococcal numbers were similar in both cheeses (~109 cfu/g) and fast-growing NSLAB lactobacilli counts were below detectable levels (<102 cfu/g). As expected, Lactobacillus wasatchensis counts were 3 x 105 cfu/g in cheeses inoculated with this bacterium and below enumeration limits in the control cheese. Starter streptococci decreased over time at both storage temperatures but declined more rapidly at 12°C, especially in cheese also containing Lb. wasatchensis. Populations of fast-growing NSLAB and the slow-growing Lb. wasatchensis reached 5 x 107 and 2 x 108 cfu/g, respectively, after 16 wk of storage at 12°C. Growth of NSLAB coincided with a reduction in galactose concentration in the cheese from 0.6% to 0.1%. Levels of galactose at 6°C had similar decrease. Gas formation and textural defects were only observed in cheese with added Lb. wasatchensis ripened at 12°C. Use of St. thermophilus as starter culture resulted in galactose accumulation that Lb. wasatchensis can utilize to produce CO2, which contributes to late gas blowing in Cheddar-style cheeses, especially when the cheese is ripened at elevated temperature.
Western Dairy Center, Utah State University; Ortakci, Fatih; Broadbent, Jeff R.; Oberg, Craig J.; and McMahon, Donald J., "Growth and Gas Formation by Lactobacillus wasatchensis, a Novel Obligatory Heterofermentative Nonstarter Lactic Acid Bacterium, in Cheddar-style Cheese Made Using a Streptococcus thermophilus Starter" (2015). Nutrition, Dietetics, and Food Sciences Faculty Publications. Paper 851.