Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods.

Consumer interest in healthy lifestyle and health-promoting natural products is a major driving force for the increasing global demand of biofunctional dairy foods. A number of commercial sources sell synthetic formulations of bioactive substances for use as dietary supplements. However, the bioactive-enrichment of health-oriented foods by naturally occurring microorganisms during dairy fermentation is in increased demand. While participating in milk fermentation, lactic acid bacteria can be exploited in situ as microbial sources for naturally enriching dairy products with a broad range of bioactive components that may cover different health aspects. Several of these bioactive metabolites are industrially and economically important, as they are claimed to exert diverse health-promoting activities on the consumer, such as anti-hypertensive, anti-inflammatory, and anti-diabetic, anti-oxidative, immune-modulatory, anti-cholesterolemic, or microbiome modulation. This review aims at discussing the potential of these health-supporting bacteria as starter or adjunct cultures for the elaboration of dairy foods with a broad spectrum of new functional properties and added value.

Compositional and biochemical changes in Genestoso cheese, a Spanish raw cow's milk variety, during ripening.

BACKGROUND: Physicochemical characteristics, proteolysis and lipolysis were studied throughout the ripening of eight batches of a traditional Spanish variety made from raw cow's milk, in order to establish a basis for its industrial production. RESULTS: The main compositional characteristics of this cheese after 60 days of ripening were its high proportion of total solids (TS; 752 g kg⁻¹ of cheese), an average content of protein (452.8 g kg⁻¹ TS) and fat (475.1 g kg⁻¹ TS) and the presence of residual lactose (12.5 g kg⁻¹ TS). Its pH value (4.04) was extremely low. Phosphorus (5.13 g kg⁻¹ TS) and sodium (8.29 g kg⁻¹ TS) were the most abundant mineral elements in cheese, whereas calcium levels (1.92 g kg⁻¹ TS) were very low. Proteolysis extension and depth were very low, which resulted in almost zero degradation of αs1- and ß-casein. Fat acidity increased during ripening, reaching final values of 50.1 mg KOH kg⁻¹ of fat. The main free fatty acid was C16:0, followed by C18:1 and C14:0. CONCLUSION: These results suggest that this variety undergoes a limited proteolysis and moderate lipolysis during ripening. The low pH, low calcium content and limited proteolysis led to a crumbly texture in this cheese variety.

Population Levels, Species, and Characteristics of Micrococcaceae during the Manufacturing and Ripening of Armada-Sobado Hard Goat's Milk Cheese.

The changes in the counts and the species of Micrococcaceae were studied throughout the manufacturing and ripening of a Spanish hard goat's milk cheese, the Armada-Sobado variety. In the milk, counts on mannitol salt agar (MSA) ranged from 2 × 104 to 5 × 104 CFU/g. These counts showed the maximum value in the curd (7 × 104 to 4 × 105 CFU/g), decreasing afterwards slowly but steadily throughout the ripening process to reach final counts on average 2 logarithmic units lower than those found in the curd. Of 280 isolates obtained from MSA during manufacturing and ripening, 66 (24%) were considered to be Micrococcaceae . Staphylococcus sciuri (22.5% of the isolates at this sampling point) and Staphylococcus saprophyticus (7.5%) were the only two species of staphylococci isolated from the milk. In the curd, S. sciuri increased its proportion (30%) whilst the percentage of S. saprophyticus remained constant. None of these species was isolated from the cheese. S. aureus was detected only in curd (7.5% of the isolates obtained at this sampling point). S. xylosus , S. capitis , S. epidermidis , and S. warneri were isolated from curd and cheese, or exclusively from cheese, but always in very low proportions. Micrococcus varians (10%) and M. roseus (5%) were the two species of micrococci isolated from the milk. M. varians increased its proportion in curd (17.5%) and could not be isolated in cheese. M. roseus appeared neither in curd nor in cheese. All the isolated staphylococcal strains were tested for production of A, B, C, and D enterotoxins. The three isolated strains of Staphylococcus aureus produced A and C enterotoxins, but neither B or D. Of 41 coagulase-negative strains only two of the Staphylococcus sciuri isolated from milk produced C enterotoxins.

Microbiological Study of León Raw Cow-Milk Cheese, a Spanish Craft Variety.

The levels of several microbial groups (aerobic mesophilic flora, aerobic psychrotrophic flora, lactic acid bacteria, Micrococcaceae, enterococci, Enterobacteriaceae, and molds and yeasts), and some biochemical parameters were investigated during the manufacture and ripening of four batches of León cow cheese produced from raw milk without the addition of starter cultures. The study of the microbial characteristics of this cheese constitutes the first step towards the establishment of a starter culture which would allow the making of a product both more uniform and safer from the point of view of health. The total microbial counts were high throughout the elaboration and ripening. Almost all the microbial groups reached their maximum counts in curd and afterwards dropped throughout the ripening process. The greatest drop was shown by Enterobacteriaceae, which had disappeared after 3 months of ripening. Lactic acid bacteria were the major microbial group, reaching counts similar to the total aerobic mesophilic flora at all sampling points. Lactococcus lactis subsp. lactis dominated in milk (62.5% of the isolates obtained in de Man-Rogosa-Sharpe (MRS) agar at this sampling point), curd (82.5% of the isolates obtained at this sampling point) and one-week-old cheese (85% of isolates obtained at this sampling point), while Lactobacillus casei subsp. casei was the most predominant species in eight-week-old cheese (55% of isolates obtained at this sampling point) and twelve-week-old cheese (47.5% of isolates obtained at this sampling point). According to our data, a starter suitable for the production of León cow cheese would be made up of these two species. Some species of Leuconostoc or enterococci could also be added to this starter with the aim of improving the organoleptic characteristics of the final product or to emphasize the characteristics of this variety.