An epifluorescent microscope fitted with a ‘Chalnicon’ closed circuit television camera linked to an Optomax System III image analyser was used to count bacteria and somatic cells on membrane filters prepared from milk by the direct epifluorescent filter technique (DEFT). For both bacteria and somatic cells, the semi-automated DEFT count of low count milk exceeded the visual DEFT count but this difference became proportionately less as the count increased. There was close agreement between the semi-automated and visual DEFT counts over the range 105-5 times 106/ml for bacteria and 3 times 105-5 times 106/ml for somatic cells. The semi-automated DEFT count of bacteria and somatic cells correlated well with the plate count and Coulter count respectively, with correlation coefficients of 0.83 and 0.81.

Semi-automated counting of bacteria and somatic cells in milk using epifluorescence microscopy and television image analysis.

.. . .. . ....... .... ........ .... .. .... ... . ....................... . .......... ... ... . ....... . .. ...... . . . . Introduction ...... .... . ........... .. ... ..... . . . ... . . . .. .... . .. .... . ... . . . ... ... . .... ... . . .... . .. .. .. ......... . The IDF definition of mastitis ..... .. . .... . ... .. .... .. .. ... . ..... ... ... ... ... . .. . .......... . . .. .. . . . . . . .. ... . .. . Evolution of the diagnosis of mastitis ... . ....... .. ......... . .. . ..... . ........... . ..... . ... . . ...... .. ............ . 1. The diagnosis of mastitis prior to 1889 .... ........ . . . ....... . .. .... .. .... ........ . . .. ... ... . . . . . .. .. . . . .... . 2. The diagnosis of mastitis between 1889 and 1899 .... ............. ..... . .. ....... .. . ..... . ...... . ...... . ..... . 3. The diagnosis of mastitis between 1900 and 1909 .... . ........ . ... . . . ..... ... . .... .. ... .. . ....... ... ... . . .... . 4. The diagnosis of mastitis between 1910 and 1919 . ..... . ............ . ........ ... .. .... ........... . ......... .. . 5. The diagnosis of mastitis between 1920 and 1929 ......... . .. .. ... . ... . ..... . .. . . ... . . . . ...... . .. . .. ..... .. .. . 6. The diagnosis of mastitis between 1930 and 1939 ......... . .... .. .. . . .. . .. . .. ..... .... ... .. .. . . ... . . . .. .. .... . 7. The diagnosis of mastitis from 1940 to date . .. . ..................... . . ... . . . ........ . .. .. ... ..... .. ... . ... .. . The reliability of the current diagnosis of mastitis ... .. ............... . .. . . .. . ......... . ..... .. .... ... . . ........ .. . 1. The clinical diagnosis of mastitis ... .......... . .. .... .. . ... . . .......... . . . .... ... . . .. . . ...... . .... . ........ . 2. The bacteriological diagnosis of mastitis ....... . .... .. ........ . ................ ...... .. . .... .. . ... ........ .. . 3. The cytological diagnosis of mastitis .. . .... .. ....... ..... ... .... ............... . . . . . ... ...... .... . ....... . . . Cellular equivalence of DNA in milk ... ... . ....... ....... . .. . ....... ... .. .. . . ... .. . . . ... . . . .. . .... . . . . .... . Cellular fluctuations in milk ..... .. . .......... . .... . ..... . .... .. .... ....... .. . ....... . ... . . .. ... .. . ... .. . . . Physiological significance of epithelial cells in milk ......... . ...... . ... .. ........... . .... .. ...... .... .. ..... . . . Physiological significance of leucocytes in milk ..... ......... .. . . ... ..................... . ... .. .... ..... . .... . Somatic cells in milk and the diagnosis of mastitis . . . . ....... . ... . . .. ...... ....... ..... . .' ... .. ... ... . ... . .. .. . Conclusions ..... . . .. ........ . ........................ . .... . . .. .. . . . ... ... .. .. . .. . . . . ... . .. . . . ... .... .. ..... . . Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... .... . ........ . ... . . ... ... ... . .. .... ...... . References ........ ..... .... .. ........... .. .. . ... . ............ ....... .. . .. . . . . ........ . .. ....... ....... .. . . . . . Appendix .......... . .. . ... .. . .. ... . .. ....... .. .... ..... . . ... . . .. . .. . .. . ... ........... . .. .. .. . ......... .... .. .

The diagnosis of bovine mastitis with particular reference to subclinical mastitis : a critical review of relevant literature

Comparison of counts using a breed-type smear and millipore membrane methods on fresh and preserved milk samples.

Fresh milk samples and potassium dichromate preserved milk samples were stored at both ambient, approximately 21 degree C, and refrigerator temperatures, 3-5 degree C, for varying lengths of time before somatic cell counts were performed on an electronic particle counter Fresh milk samples stored at ambient temperatures became unacceptable for somatic cell counting by 16 hours while those stored in the refrigerator were acceptable for up to three days Once dichromate had been added to the milk no difference in cell counts attributable to temperature of storage were detected and there was very little change with time up to 14 days On the average the addition of the dichromate elevated the cell counts/mL As well a method of rapid fixation of milk involving the addition of glutaraldehyde prior to counting was evaluated In fresh milk samples the use of glutaraldehyde as a fixative required adjustment of the threshold setting on the cell counter in order to produce results comparable to those obtained from formalin fixed samples With dichromate preserved milk samples, glutaraldehyde fixation generally elevated the cell counts but the results were variable

The effects of storage and method of fixation on somatic cell counts in bovine milk

Membrane filters (MFs) were used before agar was adopted by microbiologists, when Fick (1855) made nitrocellulose membranes as substitutes for animal membranes in dialysis experiments (Presswood, 1981). However, it was some time before a useful preparation method was developed (Zsigmondy and Bachmann, 1918), leading to commercial production by Sartorius-Werke AG (Gottingen, Germany). Before World War II, MFs were used primarily for sterilization. However, devastation of laboratories and contamination of water supplies by bombing raids led to their application for determining water safety by German hygiene institutes. After the war, the first MF methods for culturing organisms were published (Muller, 1947a, Muller, 1947b).

G.C. Ashton

Papers

Comparison of counts using a breed-type smear and millipore membrane methods on fresh and preserved milk samples.

Uniformity of Solids on Smears of Milk Containing Glycine-2-14C and Its Relation to Cell Distribution

Solids Distribution in a Milk Smear Containing Algal-14C-Protein