"Carbon Group" (40 results)

Enterococcus Confirmatory Agar is used to confirm the presence of enterococci in water and other sources of sanitary interest. The presence of intestinal enterococci, also known as faecal streptococci, is an indicator for faecal contamination, especially when the contamination occurred a long time ago and the less resistant coliform bacteria, including Escherichia coli, may already be dead at the time of analysis. Casein peptone provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group essential for bacterial growth and dextrose is the fermentable carbohydrate providing carbon and energy. Sodium azide inhibits Gram-negative bacteria and Methylene blue is an inhibitor of some Gram-positive bacteria. Methylene blue is also the pH indicator. Bacteriological agar is the solidifying agent.

To the prepared test tubes, to cover half of the slanted surface, aseptically add a volume of either Enterococcus Selective Broth (Cat. CL-1204) or Enterococcus Confirmatory Broth (same formulation as this medium but without the agar). Using growth from KAA Presumptive Broth (Cat. CL-1209), inoculate both the surface and the broth in the Confirmatory Agar/Broth mixture tube.

KF Streptococcal Agar with Bromocresol Purple is a selective medium for the isolation and enumeration of faecal enterococci in water, foodstuffs, and other materials. It can be used for the plate count of enterococci in water samples and for determining the presence of Enterococcus faecalis in milk and its derivatives, as well as in other foods. The isolation and enumeration of faecal enterococci is made according to APHA for the examination of water (1998) and foodstuffs (1992).

Peptone mixture provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Maltose and Lactose are the fermentable carbohydrates as carbon and energy sources. Sodium glycerophosphate is a buffering agent. Sodium azide is a selective agent that inhibits Gram-negative bacteria. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bromocresol purple is a pH indicator. Bacteriological agar is the solidifying agent. The addition of TTC 1% Supplement (2,3,5 Trypheniltetrazolium chloride) allows faecal enterococci to develop a red colour as the result of the reduction of tetrazolium to formazan, an insoluble red pigment, by actively growing microbial cells.

Violet Red Bile Agar with Glucose (VRBG) 5kg is a selective medium that contains Bile and Violet Red dye, for the isolation and enumeration of enterobacteria. It is based on MacConkey Medium (Cat. CL-1052) used for the detection and enumeration of bile tolerant Gram-negative Enterobacteriaceae in dairy products and foods. In this medium, the lactose is replaced by glucose as the carbohydrate. VRBG agar is the preferred medium for use in investigations into raw materials, processed foods, and plant hygiene. The Enterobacteriaceae group includes lactose-fermenting coliforms bacteria and non-lactose fermenting species like Salmonella and Shigella. Pancreatic digest of gelatin provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is the source of vitamins, particularly of the B-group. Glucose is the fermentable carbohydrate providing carbon and energy. Glucose fermenters form red colonies in the presence of the pH indicator neutral red. Bile salts and crystal violet inhibit Gram-positive bacteria. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Bacteriological agar is the solidifying agent.

The European Pharmacopoeia recommends this medium for: “Microbiological examination of non-sterile products: test for specified microorganisms”. This medium can be used for the testing of bile-tolerant Gram-negative bacteria in products. ISO 21528 proposes VRBG Agar for the detection and enumeration of Enterobacteriaceae. The pour plate method suppresses the growth of Gram-negative non-fermenting bacteria due to its semi-anaerobic conditions. The fermentation of glucose is likewise stimulated and results in the formation of purple-red colonies, clearly visible, surrounded by a zone of the same colour. Note that coliforms will ferment the glucose and produce acid with or without gas. Klebsiella and Citrobacter, which are more heat-resident than coliforms, also grow in this medium and can indicate a production process defect (insufficient heating).

Reinforced Clostridial Agar is recommended for the cultivation and enumeration of anaerobes, particularly Clostridium, and other microorganisms in foods and clinical specimens. Hirsch and Grinstead formulated Reinforced Clostridial Medium (Cat. CL-1007) and found that this medium is superior to others in supporting growth and producing high cell counts of Clostridia. When incubated anaerobically, this medium grows various anaerobes and other bacteria. It has also been demonstrated that it can be used to develop vegetative cells in assays of Clostridium perfringens. Peptone and beef extract provide nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate providing carbon and energy. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Starch in the medium acts as a growth factor, probably functioning like a colloid protector and neutralizes toxic products that form during the development of the organisms. L-Cysteine hydrochloride is the reducing agent and Sodium acetate is the buffer. Bacteriological agar is the solidifying agent. Since it is a non-selective enrichment medium, it allows the growth of various anaerobic microorganisms and facultative bacteria when incubated anaerobically.

Brilliant Green Agar (BGA) is used for the selective isolation of Salmonella spp, other than S. typhi, in foods and clinical specimens, via Lactose/Sucrose fermentation. The Peptone mixture provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly the B-group. Sucrose and Lactose are fermentable carbohydrates providing carbon and energy. Phenol red is the pH indicator, turning the medium a yellow colour with the formation of acid because of Lactose/Sucrose fermentation. Brilliant green inhibits Gram-positive bacteria and most Gram-negative bacilli, other than Salmonella spp. Lactose/Sucrose fermenters are usually inhibited. Sodium chloride supplies essential electrolytes for transport and osmotic balance and bacteriological agar is the solidifying agent.

The medium, which has a coffee colour at the beginning will change to red during incubation at 35-37 ºC. A probable presence of Salmonellae is indicated by small, transparent, either colourless or pink or opaque-white colonies, often surrounded by a pink or red zone. Some of the uninhibited Gram-negative, Lactose/Sucrose fermenting organisms present opaque green-yellow colonies, surrounded by a yellow halo. Other lactose negative microorganisms, such as Proteus spp., form colonies of a pale pink or red colour, transparent and surrounded by a brilliant red halo.

Reinforced Clostridial Medium is a semi-solid medium that is recommended for the cultivation and enumeration of anaerobes, particularly Clostridium and other microorganisms in goods and clinical specimens. Hirsch and Grinstead formulated it in 1954 and their work demonstrated that the medium outperformed other media when supporting the growth of Clostridium from small inoculum and produced higher viable cell counts. Peptone and beef extract provide nitrogen, vitamins, minerals, and amino acids that are essential for growth. Yeast extract is the source of vitamins, particularly of the B-group and dextrose is the fermentable carbohydrate providing carbon and energy.

Sodium chloride supplies essential electrolytes for transport and osmotic balance. Starch in the medium acts as a growth factor, probably functioning like a colloid protector, and neutralizes toxic products that form during the development of the organisms. L Cysteine hydrochloride is the reducing agent and sodium acetate is the buffer. Since the medium is a non-selective enrichment one, it allows the growth of various anaerobic microorganisms and facultative bacteria when incubated under anaerobic conditions. The European Pharmacopoeia, USP, recommends the Reinforced Clostridial Medium for “Microbiological examination of non-Sterile products: test for specified microorganisms” for the testing of Clostridia in products.

Listeria Enrichment Broth with Supplements is the modified version of Listeria Fraser Broth ISO Cat. CL-1182. The medium is used for the selective enrichment and enumeration of Listeria monocytogenes and other Listeria species in all food types, including milk and dairy products, and environmental samples. The antibiotics are already included in the formula. Listeria monocytogenes is the bacterium that causes the infection listeriosis which is an illness that is vital when it comes to food safety. The control of this bacterium is important as it has the ability to grow at temperatures as low as 3°C. Listeria is killed by cooking and pasteurization so can be found in raw milk and foods made from raw milk as cheeses (particularly soft-ripened varieties) or ice cream as they do not require cooking. It can also live in food processing plants and contaminate a variety of processed meats.

Soy peptone and tryptone provide nitrogen, vitamins, minerals, and amino acids essential for growth. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Dextrose is the fermentable carbohydrate providing carbon and energy. Yeast extract is source of vitamins, particularly the B-group essential for bacterial growth. Potassium phosphates act as a buffer system. Nalidixic acid blocks the DNA replication of susceptible bacteria and acts against many Gram-negative bacteria. The Acriflavine and cicloheximide are the Gram-positive selective components.

WL Differential Agar is a selective medium for the isolation and enumeration of microbial flora used together with WL Nutrient Agar (Cat. CL-1086) for the control of the manufacture of beer and other fermentation processes by yeasts. Both media are widely used in the industries of vinegar, bread yeasts, grape and wine-growing and distilled spirits. In the production of yeasts for the bakery and distillery industries, the pH of the media is adjusted to 6.5. The medium allows the selective multiplication of yeasts in fermentation liquids, which contain a microflora mix consisting of fungi and bacteria. When the number of yeasts present is relatively small, certain bacteria can also be detected.

Tryptone provides nitrogen, vitamins, minerals, and amino acids essential for growth. Dextrose is the fermentable carbohydrate providing carbon and energy. Yeast extract is a source of vitamins, particularly of the B-group and monopotassium phosphate is the buffer. Potassium, Calcium and Ferric chlorides all provide essential ions for the osmotic balance. Magnesium and Manganese sulphates are sources of divalent cations. Bromocresol purple is the pH indicator and bacteriological agar is the solidifying agent. The addition of 0.004 grams of Cycloheximide converts the WL Nutrient formula into a differential medium, which inhibits the development of yeasts and moulds while permitting the notable proliferation of the bacteria present in the fermentation liquids and subsequent identification and enumeration.

Endo LES Agar Base is a modification of Endo Agar Base (Cat. CL-1118), for testing water by the membrane filter technique. It uses Lauryl Sulphate Broth (Cat.CL- 1310) as an enrichment to obtain greater growth. LES stands for Lawrence Experimental Station which is a standard formula for testing waters and is also specified in the coliform’s fermentation technique.

Like Endo Agar, it uses fuchsin to differentiate between positive lactose-fermenting and lactose non-fermenting bacteria. Acetaldehyde production by lactose fermenting organisms such as Escherichia coli produce characteristic red colonies and a red surrounding area, marked by its reaction with Sodium sulphite in the presence of fuchsin. Lactose non-fermenters form colourless, transparent colonies.

Casein and Meat peptones, and Tryptose provide nitrogen, vitamins, minerals, and amino acids that are essential for growth. Yeast extract is a source of vitamins, particularly of the B-group and lactose is the fermentable carbohydrate providing carbon and energy. Potassium phosphates act as a buffer system. Sodium deoxycholate inhibit growth of gram-positive bacteria. Sodium lauryl sulphate partially inhibits organisms other than coliforms. Sodium chloride supplies essential electrolytes for transport and osmotic balance and bacteriological agar is the solidifying agent.

Note: Basic fuchsin is a potential carcinogen and precautions should be taken to avoid inhalation of the dye powder as well as contact with skin.

Yersinia Select Agar Base is a selective and differential medium when used with supplements. The formula is based on the CIN Agar described by Schiemann and is recommended by ISO 10273 for the isolation and detection of presumptive pathogenic Yersinia enterocolitica from a variety of clinical and food samples. Antibiotics are added as a supplement to inhibit the accompanying flora. The growth of Yersinia is promoted by pyruvate as well as by the nutrients content in the base.

Yersinia degrades the mannitol of the medium to an acid form. This makes the colonies turn to a red colour due to the neutral red indicator. Mannitol fermentation in the presence of neutral red produces a characteristic “bull’s-eye” colony, colourless with a red centre. Mannitol is the fermentable carbohydrate, source of carbon and energy. Enzymatic digest of gelatin and the enzymatic digest of casein and animal tissues provide nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group.

Sodium pyruvate is added as a source of energy and as a protective substance to overcome oxygen toxicity biologically produced by the organisms. Sodium chloride supplies essential electrolytes for transport and osmotic balance. Magnesium sulphate is an ion required in a large variation of enzymatic reactions, including DNA replication. Neutral red is the pH indicator. Selective inhibition of Gram-negative and Gram-positive organisms is obtained through crystal violet, sodium desoxycholate and Irgasan (triclosan). Cefsulodin and novobiocin improve the inhibition of normal enteric organisms.

Brucella Agar is rich in nutrients and growth factors which makes it suitable to grow and isolate fastidious microorganisms. It can be used to successfully isolate Brucella from diverse specimens contaminated with microflora, both saprophytes and commensals in clinical samples as well as in food. The medium is used to produce clostridial toxins and can be utilised in the isolation of many anaerobes of human and animal origin. Food samples can be inoculated directly on the plates of Brucella Agar, while clinical specimens are more convenient as suspensions or macerations in sterile saline solutions.

Meat peptone and casein peptone provide nitrogen, vitamins, minerals. and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Sodium bisulphite is the reducing agent; Sodium chloride supplies essential electrolytes for transport and osmotic balance. Dextrose is the fermentable carbohydrate providing carbon and energy. The addition of blood provides extra growth factors for fastidious microorganisms. Bacteriological agar is the solidifying agent. The addition of the Brucella Supplement (Cat. CL-6017) enhances the medium’s selectivity for the growth of Brucella. For a better growth, Polyenrichment Supplement (Cat. CL-6011) and Polyenrichment CC Supplement (Cat. CL-6071) may be added if required. Brucella species are level 3 pathogens and cause brucellosis, a zoonotic disease. It is usually transmitted through milk, dairy products, meat, and direct contact with infected animals.

Note: To obtain an excellent medium for anaerobes, add 5 mg/ml of hemin and 10 μg/ml of vitamin K1 (fitomenadione) to the basal medium. Inoculate and incubate in anaerobic conditions.

Vogel-Johnson Agar is a selective and differential medium used for the early detection of Staphylococcus aureus by identifying the coagulase-positive and mannitol-fermenting strains. The medium is well suited for the detection of staphylococci carriers as well as studies of sanitary concern. S. aureus reduce the potassium tellurite to the metal tellurium and result in the growth of black colonies. The fermentation of mannitol is indicated by the yellow zones around the black colonies and changes the red colour of the medium to yellow.

Tryptone provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Mannitol is the fermentable carbohydrate providing carbon and energy potassium tellurite, lithium chloride and the high glycine concentration inhibit most microorganisms other than staphylococci. Phenol red is the pH indicator. Dipotassium phosphate is a buffer and bacteriological agar is the solidifying agent.

Vogel-Johnson Agar plates can be streaked heavily with a swab and incubated at 35±2 °C for 24-48 hours. It is important to look for the black colonies that are surrounded by a yellow zone. In the first 24 hours, most microorganisms except for coagulase-positive staphylococci are totally or markedly inhibited. In the 48-hour period, many coagulase-negative staphylococci, mannitol-positive and mannitol-negative begin to appear. Staphylococcus epidermidis, almost always inhibited early, forms small greyish-black colonies without yellow zones. Coagulase-positive staphylococci form black colonies on the red medium. If they ferment mannitol, the colonies are surrounded by a yellow zone. Mannitol-negative organisms do not change the red colour of the medium.