Comparative study of the physico-chemical and microbiological characteristics of raw and pasteurized camel milk

Abstract

Camel milk is three times richer in vitamin C than cow's milk, it is also rich in niacin, antimicrobial factors prostaglandins and insulin. Pasteurization is an adequate option for camel milk conservation, allowing it to be consumed by people not living in arid environments. However, the obvious problem is that people prefer to consume raw camel milk for its therapeutic virtues, which they think, loses its quality after pasteurization. Therefore, the aim of this research is to study the effect of pasteurization on camel milk nutritional and hygienic quality. This work consists on analyzing four camel milk samples: a sample of raw milk and three samples of this milk , pasteurized at 63°C/30min, 72°C/15sec and at 85°C/2min under laboratory conditions. The data was subjected to Kruskal-wallis using XL-Stat software. These results show stability of the physicochemical composition (PH, acidity, density) and chemical composition (dry matter, lactose, fat, vitamine C, protein) ( p > 0.05) of camel milk pasteurized at 63°C (low pasteurization) and instability ( p < 0.05) following pasteurization high at (85°C) except the fat content which remains intact (p > 0.05). For pasteurization at (72°C) we notice a instability (p ˂ 0.05) in pH, acidity, dry matter, vitamine C and protein, a stability in the density, fat and lactose. Only low pasteurization (63°C for 30 min) can be an alternative for the conservation of
 camel milk while preserving its nutritional quality. To study its hygienic quality before and after pasteurization, the reductase test was carried out; it shows a good to fair quality for the raw milk sample and good for the pasteurized milk sample. Contaminating and original flora were counted on appropriate culture media. Results obtained shows that the pasteurization caused a total inhibition of the pathogenic flora (Halotolerants, Coliforms and Enterobacteriaceae), and partial destruction of the total aerobic mesophilic flora (TAMF), psychrotrophic and thermophilic lactic acid bacteria. This study confirms that the nutritional quality can be preserved almost intact after pasteurization at 63°C for 30min. In addition, pasteurization has an important role in camel milk sanitation by inhibiting pathogenic flora.