Non-lactose fermenters

Shigella are nonmotile, gram-negative, non-lactose-fermenting rods and are members of the family Enterobacteriaceae. There... 

Salmonella are motile, non-lactose-fermenting, gram-negative bacilli. In salmonellosis, the organisms penetrate the epithelial lining to the lamina propia with production of diffuse inflammation. The distal ileum and colon are sites of infection. 

Yersinia spp. are non-lactose-fermenting gram-negative coccobacilli that are widely distribnted in natnre. The genns Yersinia includes six species known to cause disease in humans. The best known species is Y pestis, the causative agent of plague, which is usually spread by bites from infected animals, such as fleas, rodents, or cats. Y. enterocolitica and, to lesser extent, Y. pseudotuberculosis are most likely associated with intestinal infection, but overall, both are a relatively infrequent cause of diarrhea and abdominal pain. More than 50 serotypes of Y. enterocolitica exist of these, serotypes 0 3, 0 8, and 0 9 are associated most frequently with enterocolitis. Infections are reported commonly from northern Europe, and the peak incidence occurs during the winter months. 

Desoxycholate Agar is recommended by APHA for the counting of coliforms in dairy products. APHA recommend placing a sample (1 ml) in the petri dish and preparing a pour plate of medium. Once this has set, a further 5 ml of uninoculated medium is poured over the plate. Plates are incubated at 35 °G for 18-24 hours and coliform numbers can be estimated by counting all dark red colonies. Enteric bacteria which are non-lactose fermenters form colourless colonies, whilst non-enteric bacteria are inhibited by the desoxycholate. 

Differential media these distinguish colonies of specific microbes from others. When a culture medium containing certain substances helps to distinguish the differing properties of different bacteria, it is called differential media, e.g., MacConkey agar. It is also an indicator medium. It contains peptone, agar, lactose, sodium taurocholate and nentral red. The lactose fermenters form pink colonies while non-lactose fermenters produce colourless or pale colonies. Blood agar it serves both as an enriched as well as an indicator medium and shows different types of haemolysis. 

The fiber of rice bran products, especially the RiceMucil is helpful in maintaining normal gastrointestinal and colon health (Tomlin and Read, 1988). It helps in bowel regularity. Patients with irritable bowel syndrome, inflammatory bowel disease and colitis get excellent relief with RiceMucil . As has been mentioned in the earlier part of this chapter, the fiber of rice bran is non-bloating and lactose free, and the acidic environment the fiber creates during the fermentation of undigested food improves colon health and induces all the healthy enzymes and fnendly bacteria to proliferate (Folino et al, 1995 Life Sciences News Letter, 1999). It has been scientifically demonstrated to have an excellent nutritional support for gut and colon health. 

The characteristic features of the coliforms are non-sporing, Gram-negative rods, which are bile tolerant and able to ferment lactose at 37 °C producing acid and gas within 48 hours. The term faecal coliform was used to describe coliforms capable of fermenting lactose to acid and gas within 24 hours at 44 °C. The term thermotolerant coliforms is now used more commonly in the UK, although the term faecal coliform is still widely used elsewhere. It should be pointed out that not all thermotolerant coliforms are faecal in origin. 

Fermentable Sugars.— Four hexoses only are fermented by ordinary yeast, namely glucose, mannose, galactose, and fructose. Of the commoner disaccharides, maltose and sucrose are attacked while lactose is not. Pentoses as a class are non-fermentable by yeast. 

Lactose is a normal constituent of most urines during the lactation period, and has no pathological significance. It can be distinguished from glucose by its non-fermentability by yeast, and by the fact that it does not yield a glucosazone. 

Yeast Fermentation Teat.—The method is described on p, 114. Lactose, pentoses and glycuronic acid are the only non-fermentable copper-reducing substances likely to occur in urine, and the fermentation test should be used to check the tests of Benedict and Eehling. 

Streptoccocaceae consist of facultatively anaerobic, non-sporing, homofermentative spherical or ovoid cells, typically arranged in chains or pairs. The majority of species belonging to genus Streptococcus are parasitic in man and other animals and the association between some streptococci and a variety of human and animal diseases is established (Hardie and Whiley 1995). On the other hand, members of genus Lactococcus are widely used in the dairy industry due to their ability to produce L(-H)-lactic acid from lactose in spontaneously fermented raw milk at 20-30 °C (Teuber 1995). 

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