实验基础

Yeasts are the most significant microorganisms in all conversion steps of the grape/must/wine system. Because of their metabolic activity, yeasts play a central role in the must fermentation process and also in contamination and spoilage of the final products—wines. Consequently, on ...

The growth of microbial cells is often inhibited in environments where the water activity is much reduced. However, some microorganisms have developed various strategies in order to resist the stresses to which they are exposed. The ability to adapt to fluctuations in external osmolarity ...

Microbial proteases play an important role in industrial processes. The proteases of Bacillus spp., Mucor spp., and Aspergillus oryzae account for the bulk of enzyme production and represent aproximately 40% of the total worldwide enzyme sales (1).

Lactic acid fermentation is commonly used for food conservation. The main products of this bacterial process are lactic and acetic acids, which are toxic to many microorganisms, most yeasts included. The low pH achieved by the lactic acid fermentation, together with anaerobiosis, provid ...

Lactic acid bacteria (LAB), mainly Lactobacillus and Lactococcus species, are useful microorganisms in many biotechnological processes in the food and feed industries. Bacteriophage contaminations of this important group of Gram-positive bacteria have been reported since ...

Lactic acid bacteria (LAB) are considered weakly proleolytic when compared with many other groups of bacteria (e.g., Bacillus, Proteus, Pseudomonas). However, most strains of LAB rely on a complex proteolytic system that allow them to liberate essential and growth-stimulatory amino ac ...

Lactic acid bacteria (LAB) comprise a diverse group of Gram-positive, non-spore-forming microorganisms (1). Fermentable carbohydrates are used as energy sources and are degraded to lactate (homofermentatives) or to lactate and additional products such as acetate, ethanol, carb ...

Exopolysaccharides (EPS) are exocellular polysaccharides that can be found either attached to the cell wall in the form of capsules or secreted into the extracellular environment in the form of slime.

Among the probiotic effects attributed to lactic acid bacteria (LAB), the assimilation of cholesterol (1) would be of particular interest for reducing the absorption of dietary cholesterol from the digestive system into the blood. Several studies have indicated that the cholesterol r ...

Freeze-drying is commonly used for the long-term preservation and storage of microorganisms in stock collections as well as for the production of starter cultures for the food industry. The choice of an appropriate suspending medium is of primary importance to increase the survival rate of ...

During the fermentation and ripening of dry fermented sausage, a large number of biological reactions occur in the sausage mince. Proteolysis is considered to be one of the major processes involved in texture and flavor development. Moreover, small peptides and free amino acids, thus origi ...

Lactic acid bacteria (LAB), used for centuries by man to preserve food, produce a wide variety of antagonistic compounds, including lactic acid, hydrogen peroxide, and bacteriocins. Bacteriocins are antimicrobial peptides that are bactericidal toward bacteria taxonomically c ...

Lactobacillus represents a major genus of the lactic acid bacteria that have widespread use in fermented food production. They are also found in the mouth, intestinal tract, and vagina of many animals. They produce bioantagonists compounds such as lactic acid and bacteriocins and hence are u ...

Listeria monocytogenes was discovered as a pathogen of animals and humans in the 1930s. As far as humans are concerned the organism was initially identified as a cause of abortion in early pregnancy, stillbirth, or of septicemia after an uneventful birth. Ecological surveys have demobstrat ...

The association of infection with consumption of contaminated water and foods, particularly poultry, is clearly established (1). Campylobacter food poisoning outbreaks occur either sporadically, affecting individuals and small groups suchs as families, or larger community ...

Salmonellosis is one of the most common, if not the most common infectious diseases transmitted by contaminated poultry foods (1,2). A critical goal in food processing plants and governmental control agencies is to prevent Salmonella contamination of food products and this prevention d ...

Lancefield’s group D is composed of Streptococcus equinus, S. faecalis, S. bovis, and S.faecium. S. avium (Q and D antigens). Group D is found in the intestinal tract of warm-blooded animals. The term “enterococcus” refers only to the species S. faecalis and S.faecium. The medium employed for enumerat ...

When the microbial flora invades food, two major problems arise. First is the pathogenicity of several microbes, and second are the changes on the food characteristics, such as contents of nutrients (hydrocarbons, vitamins, aminoacids, metals, etc.), bad smell, color and flavor, texture mo ...

Polymerase chain reaction (PCR) is a novel DNA amplification technique that has brought fundamental change to clinical diagnosis and rapid detection of food-borne pathogens. The technique needs little technical time and has a quick turnover. The results of PCR are accurate, sensitive, a ...

Mollicutes have restricted metabolic activities, and catabolism is primarily associated with ATP generation rather than the synthesis of metabolic precursors for anabolic metabolism (1). Nevertheless, the pathways of energy substrate metabolism and the range of substrates u ...