Rodent contamination

There are a number of situations where selective sampling would be appropriate. In food analysis, for example, it may be necessary to locate a specific adulterated portion of a lot, undiluted by perfectly good material. Other examples might be rodent contamination of flour by hair or urine, or toxic gases in a factory atmosphere where the total level may be acceptable but a localized sample may contain a harmful concentration. 

EU member countries, such as the UK, Germany and the Netherlands, have their own specifications. The European Spice Association (ESA) has a set of quality minima for herbs and spices , but has yet to finalize the cleanliness specification standards for spices and spice products. Extraneous matter and foreign matter should not exceed 1 and 2%, respectively, and should be free from live and/or dead insects, insect fragments and rodent contamination visible to the naked eye (corrected if necessary for abnormal vision). Salmonella must be absent in (at least) 25 g of material yeast and mould, 105/g (target), absolute maximum 106/g E. coli, 102/g (target), absolute maximum 103/g (Table 6.11). 

Minerals are usually analyzed by the traditional method of atomic absorption spectroscopy or with the newer induced coupled plasma analyzers. Most vitamins are analyzed by HPLC systems or colorimetric assays. Many laboratories still quantify folic acid with the use of a microbiological assay. The analysis of dietary and detergent (neutral and acid) fibers are critically important for foods and feeds, respectively. Raw materials and feeds should be examined for rodent contamination, pathogenic bacteria, molds and mycotoxins, and undesirable toxicants such as PCB, insecticides, herbicides, and heavy metals. The proper selection of ingredients will ensure the production of high-quality foods that satisfy sensory properties required for humans, and feeds that are palatable and can meet sensory properties required for domestic animals (Chapter 18). 

The separation of cells from the culture media or fermentation broth is the first step in a bioproduct recovery sequence. Whereas centrifugation is common for recombinant bacterial cells (see Centrifugal separation), the final removal of CHO cells utilizes sterile-filtration techniques. Safety concerns with respect to contamination of the product with CHO cells were addressed by confirming the absence of cells in the product, and their relative noninfectivity with respect to immune competent rodents injected with a large number of CHO cells. 

The extension of the useful storage life of plant and animal products beyond a few days at room temperature presents a series of complex biochemical, physical, microbial, and economic challenges. Respiratory enzyme systems and other enzymes ia these foods continue to function. Their reaction products can cause off-davors, darkening, and softening. Microbes contaminating the surface of plants or animals can grow ia cell exudates produced by bmises, peeling, or size reduction. Fresh plant and animal tissue can be contaminated by odors, dust, iasects, rodents, and microbes. 

Crude papain, obtained as the dried exudate of the fruit and leaves of Caricapapaya L., Cari-caceae, Is usually found to have been contaminated during collection, drying, or storage by insects, rodent hair and excreta, botanical plant parts, sand, etc. and may thereby become further contaminated by harmful bacteria and enteric organisms. 

Filthy conditions, due to rodent or insect population, may be observed in a grain warehouse. The inspector notes rat-chewed flour sacks and sacks contaminated with rat excrement. He removes a sample of sacking and flour from such contaminated areas and submits them to the analyst. Urine fluoresces under ultraviolet light. Where rodent urine is to be confirmed, the xanthydrol test is one of several that may be used. Excreta pellets may be moistened with water or an appropriate clearing solution and crushed for observation under the compound microscope. The presence of striated hair fragments indicates rodent excrement. 

An organophosphate ester commonly used in hydraulic fluids, tricresyl phosphate (TCP), and tri-ortho-cresyl phosphate (TOCP), a possible contaminant of older formulations of TCP, have been shown to alter testicular morphology, testicular function, and reproductive function in rodents after oral exposure (Carlton et al. 1987 Chapin et al. 1988 NTP 1994 Somkuti et al. 1987a, 1987b). 

The evaluation of risk has underlined the possible adverse effects both on human health after the exposure to drinking water contaminated by landfill leachate and on small rodents and aquatic species at the hypothesized condition for humans, the estimated toxic effects of the raw leachate are mainly due to the levels of ammonia and cadmium and carcinogenic effects are induced by arsenic first and then by PCBs and PCDD/Fs while ecological potential risk is mainly attributable to the concentration of inorganic compounds, in particular ammonia for small rodents, cadmium, ammonia, and heavy metals for fishes. 

Both isomers of dimethylhydrazine have been shown to be carcinogenic in rodents following chronic oral exposure and 6-mon inhalation exposure to 1,1-dimethylhydrazine. Increased tumor incidence was observed in mice, although these findings are compromised by the contaminant exposure to dimethylnitrosamine. An increased incidence of lung tumors and hepatocellular carcinomas was also seen in rats but not in similarly exposed hamsters. The U.S. Environmental Protection Agency (U.S. EPA) inhalation slope factors are currently unavailable for dimethylhydrazine. 

Two oral studies in rodents demonstrated the carcinogenic potential of dimethylhydrazines. Results of an inhalation study in mice showing an increased tumor response following exposure to 1,1-dimethylhydrazine may be compromised by the contamination of the test article with dimethylnitrosamine. Both inhalation and oral slope factors for the dimethylhydrazines have been withdrawn from IRIS. 

It is a hantavirus that is normally found in the former Yugoslavia. The natural reservoirs are small rodents and the virus is shed in their urine. Infection occurs after inhalation of dust contaminated with excreta from infected rodents or from aerosol of animal blood or fluids. Does not produce disease in animals. This is a biosafety level 3 agent. 

Secondary Hazards Unknown, but believed to be Aerosols (blood, fluids, contaminated dust) Blood and body fluids (from rodents) Fecal matter (from rodents) Fomites (from rodent habitation). 

Mammalian wildlife from uncontaminated habitats usually contain less than 0.1 to about 5 mg Ni/kg DW in tissues in nickel-contaminated areas, these same species have 0.5 to about 10 mg Ni/kg DW in tissues (Outridge and Scheuhammer 1993 Chau and Kulikovsky-Cordeiro 1995), with a maximum of 37 mg/kg DW in kidneys of the common shrew (Sorex araneus) (Table 6.6). Nickel accumulations in wildlife vary greatly between species. For example, tissues of mice have higher concentrations of nickel than rats and other rodents, while beavers and minks have higher nickel concentrations in their livers than birds in similar sites near Sudbury (Chau and Kulikovsky-Cordeiro 1995). 

Moved in November 1986 from a highly contaminated area (>20,000 Bq 137Cs/m2) to a less-contaminated area (<3000 Bq/m2) of natural pasture Reindeer muscle 137Cs 1986 (post-Chernobyl) Rodents and insectivores July-August 1986 137Cs Control site, soil... 

The risk posed to predators eating contaminated fish is determined by comparing the estimated daily intake (EDI) of fish predators (birds or mammals) with the predicted no-effect concentration in these predatory species. If adequate data are missing, the latter value was estimated from laboratory rodent or meat-eating animals (Table 3.3). 

Melioidosis Bacterial disease of rodents that can be transmitted to humans via food contaminated by rodent droppings or biting flies. 

Melioidosis is very similar to glanders. While it usually causes disease in rodents, it can be transmitted to humans via food contaminated by rodent droppings or biting flies. The primary way for terrorists to weaponize melioidosis would be to make it an aerosol. The mortality rate is 95% in untreated acute disease patients. 

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