Description
MacConkey Broth W/Neutral Red (Double strength) is recommended for detection of bacteria responsible for food poisoning, for isolation, identification and enumeration of Escherichia coli. MacConkey Broth W/Neutral Red is also recommended for the primary isolation of coliforms from large samples such as water and wastewater. MacConkey Broth W/Neutral Red has also been recommended for use in microbiological examination of foodstuffs and for direct plating/inoculation of water samples for coliform counts. The media is employed for examination of milk and dairy products and pharmaceutical preparations. The selective nature of the medium was due to the presence of bile salts, which are inhibitory towards most gram-positive bacteria. Most gram-negative bacteria grow well on the medium and they are distinguished by fermentation of lactose. Lactose fermenting strains grow as yellow. | Lactose non-fermenting strains, such as Shigella and Salmonella are colourless and transparent and typically do not alter appearance of the medium. The differentiation in this medium is based on acid production during lactose fermentation, which results in a visible colour change due to the presence of neutral red indicator. This makes detection of coliforms simple and effective during routine testing. Appropriate incubation conditions are important for accurate results. This medium allows for reliable detection when recommended guidelines are followed, confirmatory testing is required for complete identification of organisms.
