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Results for “Yogurt quality”

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PubMed2026

By comparing the effects of Lactobacillus paracasei KL1 and BK56 strains on yogurt quality, the optimal consumption time for 2 compound fermented yogurts was determined.

This study investigated the effects of 2 Lactobacillus paracasei strains, KL1 and BK56, on the physicochemical properties, microstructure, texture characteristics, and sensory quality of a compound fermented yogurt system (GK107: L. paracasei KL1, Leuconostoc mesenteroides G12S, Chr. Hansen Commercial Starter Culture; G56107: L. paracasei BK56, L. mesenteroides G12S, Chr. Hansen Commercial Starter Culture), and further integrated genomic and metabolomic analyses to infer their shelf-life and optimal consumption period. The results showed that GK107 yogurt maintained stable quality throughout the 28-d storage period (at d 28: pH 4.07; titratable acidity 93.25 °T; exopolysaccharide content 0.31 g/L; water-holding capacity 53.05%; sensory score 83), and rapidly formed a stable gel structure that persisted for an extended duration. In contrast, the quality of G56107 yogurt deteriorated during the later stage of storage (at d 28: pH 4.0; titratable acidity 98.4 °T; exopolysaccharide content 0.31 g/L; water-holding capacity 51.3%; sensory score 67). Genomic analysis revealed that, compared with the L. paracasei KL1 strain, the L. paracasei BK56 strain carried loss-of-function mutations in multiple key genes associated with flavor synthesis, polysaccharide metabolism, and proteolysis, including alsS, prtP, glpO, AWC33_RS01450, AWC33_RS00855, AWC33_RS01070, and AWC33_RS01805. These mutations may have played a role in the gradual flavor deterioration, and weak post-acidification control observed in G56107 yogurt during prolonged storage. Based on the above results, it is reasonable to suggest that GK107 yogurt is suitable for long-term storage with an optimal consumption period of 14 to 28 d, whereas G56107 yogurt is more suitable for short-term storage and recommended for consumption within the first 14 d.

Genomics↗

PubMed1976

B-complex vitamins in cultured and acidified yogurt.

Studies were to determine the effect of various factors upon B-vitamin content of cultured yogurt and to compare the B-vitamin contents of cultured and direct acidified yogurt. Incubation of yogurt culture at 42 C for 3 h yielded maximum vitamin synthesis concurrent with optimal flavor and texture qualities. A method was standardized for the manufacture of direct acidified yogurt involving the use of Stabilac acidulant and nonfat dry milk, Carboxymethyl cellulose, gelatin, and Starite. Acidified yogurt showed a slightly higher content of certain B-vitamins than the cultured yogurt due to the contribution made by various food additives. Both cultured and acidified yogurt showed good keeping quality and freedom from microbial contaminants during storage at 5 C for 16 days. However, folic acid and vitamin B12 contents decreased 29 and 60% in cultured yogurt and 48 and 54% in acidified yogurt.

Dairy Products↗

PubMed1979

Nutritional and healthful aspects of cultured and culture-containing dairy foods.

Nutritional and therapeutic qualities of fermented dairy products are reviewed. Partial hydrolysis of milk constituents (proteins, fats, and lactose) in yogurt, cheese, and other cultured dary foods appears to contribute to their increased digestibility. Lactase and other constituent enzymes of various culturing organisms should contribute to assimilation of lactose by lactose intolerant individuals. Several lactic cultures synthesize certain B-vitamins in fermented dairy products. In contrast, directly acidified dairy products do not exhibit such enhancement in B-vitamins. The hypocholestremic effect of milk is enhanced by fermentation or inclusion of lactic cultures. Lactobacillus acidophilus, Lactobacillus bulgaricus and other lactic organisms produce antimicrobial agents and natural antibiotics. However, production of natural antibacterial substances by different strains of the same species vary widely. These metabolites in cultured dairy products may be responsible for increased shelf life of the foods by inhibiting a wide spectrum of food spoilage organisms. Also, consumption of cultured products containing such natural antibacterial substances may provide the consumer with protection against disease organisms. Unfermented milk containing a specific culture or strain may be consumed to invest organisms for projected beneficial effects.

Animals↗

PubMed1977

Esophageal cancer studies in the Caspian littoral of Iran: results of population studies--a prodrome. Joint Iran-International Agency for Research on Cancer Study Group.

Epidemiologic studies were undertaken on the Caspian littoral of Iran to investigate the geographic distribution of factors that might underlie the signal differences in incidence of cancer of the esophagus. In zones of contrasting incidence and sex ratio, information was obtained on food intake, smoking and drinking patterns (including tea), other personal habits, occupation, economic and agricultural practices, and methods of food storage preservation, and preparation. The diet in the highest incidence area was markedly restricted to bread and tea. The poor quality of the diet itself was thought to have a role in the increased risk of developing esophageal cancer. The use of opium and sesame oil, consumption of sheep's milk and yogurt, the chewing of nass (confined to men), and the use of dyes (confined to women) were also more prevalent in the high incidence areas. Typical dietary items were analyzed for the polycyclic aromatic hydrocarbons, volatile nitrosamines, aflatoxins, nitrates, and nitrites. The results showed no unusual levels of any of the carcinogens tested or geographic differences.

Agriculture↗

PubMedDate not supplied

[Search of optimum survival conditions for lactic acid bacteria in powders obtained by spray drying of yoghurt].

The paper reports the results of two spray-drying tests carried out on yogurt as such or previously neutralized. The operating conditions of the drying operation were such that the temperature of the product didn't exceed 80 degrees C, and the residual moisture of the powder was about 10%, slightly higher than the B.E.T. monolayer value. The decrease of total counts was three and two decimal reductions respectively for the natural and neutralized product. This latter gave also much higher viability index as determined in a "fermenting activity" test. Also, the analyses, related to the quality of the protein fraction, strongly support the opportunity of neutralization before drying. In storage tests carried out during 8 months the survival data were higher at 5% relative humidity (corresponding to 7-8% humidity) and at 5 degrees C temperature. In all cases the better results were obtained from the powders of neutralized yogurt, even in comparison with a freeze-dried sample obtained from the natural product. The typical shape of the sorption isotherms of these products suggests that the optimum process as regard to microorganisms' survival consists in drying the neutralized product up to residual humidities of 8-10%, followed by storage, in humidity-proof containers, at temperatures of about 5 degrees C.

Dairy Products↗

PubMed2026

Isolation, identification, and genomic characterization of Staphylococcus aureus phage vB_SauL_202595 and its bacteriostatic application in dairy products.

Staphylococcus aureus is an important pathogen associated with bovine mastitis and dairy product contamination, posing economic and public health risks through the food chain. In this study, a temperate phage, vB_SauL_202595, was isolated from a dairy farm environmental sample using S. aureus SHZ-0127 as the host, and its biological characteristics, genomic features, and antibacterial activity in dairy matrices were evaluated. vB_SauL_202595 lysed 18 of 66 tested S. aureus strains, with a lysis susceptibility rate of 27.3%, including 5 highly susceptible strains, indicating a relatively limited host range. The optimal multiplicity of infection was 0.01, the latent period was approximately 30 min, and the burst size was approximately 316 PFU/cell. The phage remained stable at 4°C-37°C and pH 6-10. Genome analysis showed that vB_SauL_202595 belongs to the class Caudoviricetes, has a genome of 44,503 bp with 33.59% GC content, and encodes 63 predicted proteins. No typical antibiotic resistance genes or major virulence factors were detected; however, integrase and repressor genes were identified, supporting its temperate nature. vB_SauL_202595 inhibited S. aureus SHZ-0127 growth, reduced mature biofilm biomass, and decreased viable bacterial counts in milk and yogurt, with reductions of 1.23 and 1.42 log10 CFU/mL under representative conditions, respectively. From a One Health perspective, these findings provide foundational evidence for reducing S. aureus contamination and related antimicrobial resistance risks along the dairy chain. Overall, vB_SauL_202595 represents a candidate phage resource for dairy-associated S. aureus biocontrol research, but its limited host range and lysogeny-related genes require further safety assessment before food-related applications.IMPORTANCEStaphylococcus aureus is a major pathogen associated with bovine mastitis and a common contaminant in dairy products, causing economic losses and public health risks through the food chain. Although phage-based biocontrol has emerged as a promising strategy for controlling S. aureus contamination in dairy products, systematic evidence regarding phage activity in actual dairy matrices remains limited. In this study, we isolated and characterized a dairy farm environment-derived temperate phage, vB_SauL_202595, and evaluated its biological characteristics, genomic features, host range, stability, biofilm removal ability, and antibacterial performance in milk and yogurt. These findings provide foundational experimental evidence for phage-based dairy biocontrol against S. aureus. However, due to its limited host range and lysogeny-related genomic features, vB_SauL_202595 should be considered a candidate phage resource for further study. Broader validation, including phage-cocktail testing, long-term storage assays, product quality assessment, and regulatory safety evaluation, is needed before practical application.

Staphylococcus aureus↗