MICHAELA HEMPEN, FRED UNGER, SUSANNE MÜNSTERMANN, KARL-HANS ZESSIN
International Trypanotolerance Centre, Consumer Safety and Public Health, The Gambia
Free University Berlin, Institute for Parasitology and International Animal Health, Germany
Since 1996, small scale milk processing has been introduced in the Kolda region, Casamance, Senegal. The first pasteurization unit has been put in place with the help of Vétérinaires Sans Frontičres. Up to now, there are five units in Kolda, two in Tambacounda, three in Vélingara and one in Kédougou. The establishment of these pasteurization units initiated (1) the implementation of an effective milk collection system with better possibilities for milk producers to commercialize their products and (2) the availability of new dairy products of better quality.
This study intended to characterise the different pasteurisation units and the supplying milk collection system. Emphasis was put on the evaluation of the effectiveness of the applied methods of milk pasteurization and processing. The existing pasteurisation units can be classified into different categories: traditional, slightly advanced and advanced, depending on input in equipment and technical skills. These categories are also reflected in the quality of their products.
Bacteriological analysis was performed on milk before and after the pasteurisation/cooling process. Results of raw milk samples (n=196) showed high counts of mesophilic bacteria (87.8% above 2cfuml) and also of coliform bacteria (52.0% above 5cfuml) and E. coli (27.0% above 5cfuml). Other bacteria isolated were coagulase-positive Staphylococci (34% above 1cfuml), Bacillus cereus (present in 35.2%) and HS-reducing Clostridia (present in 11.2%). Salmonella spp. were isolated in three samples (1.5%) and Listeria spp. in only one sample (0.5%).
Pasteurization reduced considerably the bacterial load. Analysis of samples of pasteurized milk (n=64) proved the reduction of mesophilic bacteria from average values of 107 to cfuml, the number of coliform bacteria were reduced from average values of 105 to cfuml, E. coli from 102 to cfum and coagulase-positive Staphylococci spp. from 102 to cfuml. Salmonella spp. and Listeria spp. were not present in pasteurised milk. But Bacillus cereus and HS-reducing Clostridia spp. were still isolated from 50% resp. 7.5% of the pasteurized milk samples.
Small scale local pasteurisation units contributed significantly to secure regular income for dairy farmers through the production of value-added milk products.
Keywords: Milk hygiene, pasteurisation, Senegal