Rodent hairs

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. 

Tetrachlorodibenzofuran (TCDF) causes wasting syndrome, thymic atrophy, and immune suppression in rodents, hair and fingernail loss in... 

Stored plant drugs are often found to be contaminated by rat and mice hairs, urine and faeces. Infested drugs are not recognised as official by the British Pharmacopoeia which states in the General Notices that Vegetable drugs are required to be free from insects and other animal matter and from animal excreta . Insects and rodent hairs (an indicator of rodent faecal contamination) can be recovered by preferential wetting of their exoskeletons by paraffin. Microscopical examination can establish the type of insect or rodent involved. 

Separating insect fragments and rodent hairs from commeal and flour. 

In the tomato and fly eggs experiment the unwanted material was floated to the top. In this case, the waxy surface of the chitinous insect fragments or the oil-covered rodent hairs are wetted by mineral oil and floated away from the more polar starchy commeal and flour. The water and solid residue are drained away, and the oil layer filtered, leaving the insect fragments and some bran particles behind. These then are examined with a microscope. 

Rodent hairs can be distinguished from human hairs by their dark spotted appearance (Figure E49-2, p. 677) At least a 80x microscope is required to see the medulla (dark center section) of a hair. Mice hairs have the medulla sprinkled throughout whereas rat hairs have elongated clumps from one side to the other. Animal hairs usually have half or more of the hair width as medulla, whereas human hairs have less than half. Synthetic fibers have no medulla. Figure E49-2, p. 677, shows the medulla pattern for mice and rats. 

Figure E49-2. Rodent hairs 80x upper - mouse hair, lower rat hair.

Rinse the whole apparatus again with distilled water and filter these washings. Alcohol was used to dissolve the mineral oil and help free the fragments and rodent hairs. Soap solution was used to dissolve the oil film. 

There can be many types of extraneous matter but in general the micro-analytical test is mainly directed to the determination of rodent hairs, and of insect, mould and other fragments. If rodent hairs are found there is likely to be contamination with excreta since rodent faeces always contain a mass of rodent hair. There is a limit to the implications of the test, but while there is no direct evidence of harm to health from the presence of faecal matter, such contamination is most undesirable. 

The technique of the micro-analytical procedure is dealt with at length in the U.S. Food and Drug Technical Bulletin No. D and the A.O.A.C, but a method suitable for cereals and adaptable to other farinaceous products has been fully described by Kent-Jones, Amos, Elias, Bradshaw and Thackray. This procedure retains rodent hair, insect fragments and even mould fragments without losing their distinctive microscopic features. For the extraction and collection of extraneous matter the following procedure is recommended ... 

The separated and collected extraneous matter is examined microscopically and counted, normally at a magnification of 35 to 70. It is convenient to work at a magnification of about 50 (although 35 would suffice) and a field of view of about 3 mm. With an ordinary microscope this is obtained with a 1-inch objective and a X 8 eyepiece some sort of mechanical stage is also desirable. Since the most important factor is the number of rodent hairs reported, only typical rodent hairs should be reported as such photographs are given by Kent-Jones et al. ... 

Melville proposed a method for the isolation of beetle fragments from powdered vegetable drugs, dependent on solution of the vegetable matter in this procedure rodent hairs would be destroyed. 

Extraneous material, filth, insect fragments, rodent hairs, rodent excreta... 

---