Salmonellae

Media containing tetrathionate, which is also toxic to E. coli, is used in a similar manner to isolate Salmonella species. This medium does allow the growth of Proteus, which may be inhibited by the addition of the antibiotic novobiocin, thus rendering the medium specific for Salmonella. Tetrathionite broth may be used for the enrichment of contaminated material containing Salmonella. 

Xylose lysine desoxycholate agar is also useful for distinguishing Salmonella and Shigella, Salmonella producing red colonies with black centres, and Shigella producing red colonies without black centres. Non-pathogenic coliforms produce yellow colonies. 

Some Salmonella species do not conform to the general description of the genus. 

Group Status Behaviour pattern Micro-organisms 

1 Spoilage + + + + Zygosaccharomyces bailii Saccharomyces cerevisiae Torulaspora delbrueckii Schizosaccharomyces pombe 

3 Hygiene — + + Geotricium candidum Trichosporon spp. Rhodotorula glutinis (red/pink yeast) Bacillus spp. (bacteria with 

Pr = preservative resistance, principally common chemical agents, e.g. benzoic acid. 

Os = growth at high osmotic pressure sugar 60°Brix. 

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Specific bacteriostatic activity against Escherichia coli (681, 896, 899), Staphylococcus aureus (681, 896), Cocci (900), Shigella dysenteriae (681), Salmonella ryphi (681), Proteus vulgaris (681), Pseudomonas aeruginosa (681), Streptococcus (889, 901, 902) and Pneumococcus (901-904). 

Poultry, susceptible to microbiological deterioration, is an excellent substrate for Salmonella. Therefore, the temperature is reduced as rapidly as possible after slaughter. Packagiag at factory level is in soft film, ie, low density polyethylene or plastici2ed PVC, which retards water-vapor loss and permits oxygen entry. 

Pneumogstis carini pneumonia (PCP), the most common of the opportunistic infections, occurs in more than 80% of AIDS patients (13). Toxoplasmosis, a proto2oan infection of the central nervous system, is activated in AIDS patients when the 004 count drops and severe impairment of ceU-mediated immunity occurs. Typically, patients have a mass lesion(s) in the brain. These mass lesions usually respond well to therapy and can disappear completely. Fungal infections, such as CTyptococcalmeningitis, are extremely common in AIDS patients, and Histop/asma capsulatum appears when ceU-mediated immunity has been destroyed by the HIV vims, leading to widespread infection of the lungs, Hver, spleen, lymph nodes, and bone marrow. AIDS patients are particularly susceptible to bacteremia caused by nontyphoidal strains of Salmonella. Bacteremia may be cleared by using antibiotic therapy. 

Proper refrigeration prevents the growth of some microorganisms, such as Salmonella and the production of toxins, such as Staphylococcus aureus. The growth of bacteria Tscherichia coli and Bacillus cereus is substantially checked by proper cooling and handling of milk. Table 14 Hsts diseases transmitted by cows to humans. Pasteurization is the best means of prevention. 

Celanese Chemical Co., Inc., Mutagenicity Evaluation of n-PropylAlcohol in the Ames Salmonella Microsome Plate Test, Litton Bionetics, Inc., Kensington,... 

Salmonella heidelberg S. montevideo S. typhimurium S. enteritidis Sarcina lutea Serratia marcescens... 

Literature reports iadicate that sodium sorbate causes weak genotoxic effects such as chromosomal aberrations and mutations ia mammalian cells (172,173). This effect is thought to be caused by oxidative products of sodium sorbate ia stored solutions (173—175). The main oxidation product of sodium sorbate, 4,5-oxohexenoate, is mutagenic ia a Salmonella mammahan-microsome test (176). Sorbic acid and potassium sorbate were not genotoxic under the same test procedures (167,172,174—177). 

Live vectors (131,133) are another appHcation of genetic engineering. In this case, the genes from a pathogen are inserted into a vaccine vector, such as salmonella or vaccinia. In the case of salmonella, it will be possible to develop an oral vaccine. Vectors for this appHcation include salmoneUa, BCG, poHo, adenovims, and vaccinia. 

Fermentations in larger vessels and the final trade fermentation are conducted under quasi-stetile conditions, and yeast growth is accompanied by some growth of contaminant bacteria. These are generally lactic acid-producing organisms but are sometimes coHform bacteria the occurrence of Salmonella in fermentor Hquids has not been reported. Massive contamination with Oidium lactis or wild yeasts has been reported. 

Sodium chlorite is not Hsted by the USEPA or any regulatory authority as a carcinogen. Studies conducted ia mice and rats did not show an increase in tumors in animals exposed to sodium chlorite in thek drinking water. Sodium chlorite has been found to have mutagenic activity in some in vitro test systems such as the Ames Salmonella reverse mutation assay without the presence of metaboHc activators. The significance of these test results in regard to human health is not clear because of the oxidizing effects of the chlorite ion (149). 

In general, exempt colorants have less coloring power than certified colorants and thus have to be used at higher concentrations. Some, particularly those of plant origin, tend to be less stable, more variable in shade, and therefore more compHcated to use than certified colorants, and are more likely to introduce undeskable flavors and odors into the products in which they are incorporated. Also, depending on thek nature and origin, exempt colorants can vary substantially in composition from batch to batch, are more likely to be contaminated with undeskable trace metals, insecticides, herbicides, and bacteria such as Salmonella and can be more difficult to obtain in steady supply compared with certified colorants. 

Alcohols, particularly ethanol [64-17-5] and 2-propanol [67-63-9] are important disinfectants and antiseptics. In the aUphatic series of straight-chain alcohols, the antimicrobial activity increases with increasing molecular weight up to a maximum, depending on the organism tested. For Staphylococcus aureus the maximum activity occurs using amyl alcohol [71-41-0], for Salmonella typhosa, octyl alcohol [111-87-5], CgH gO (43) ioT Mycobacterium tuberculosis... 

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