Impact of Refrigeration on the Shelf Life, Biochemical and Hygienic Quality of Raw Dromedary Camel Milk Obtained in Extensive and Semi-Intensive Breeding Systems from Southeastern Algeria

AbstractThis study aims to assess the impact of refrigeration and storage duration on physicochemical and microbiological properties of dromedary camel milk in extensive and semi-intensive breeding system. Camel milk samples were obtained from the Sahrawi healthy dromedaries (Camelus dromedarius) during autumn. The physicochemical parameters measured included pH, density, titratable acidity, total dry matter, ash, fat, lactose and protein contents. The microbiological quality was evaluated by counting total aerobic mesophilic flora (FAMT) and the presence of coliforms. Initial samples were analysed and stored at 4°C for up to 29 days to monitor the changes.The pH of milk from the extensive system was higher (6.6 ± 0.2) than the semi-intensive system (6.2 ± 0.2). Dornic acidity was lower in extensive milk (18.5 ± 0.5°D) than in semi-intensive milk (20.5 ± 0.7°D). Furthermore, the density was greater in extensive milk (1.0262 ± 0.0001) relative to semi-intensive milk (1.0192 ± 0.0001) and the ash content was lower in extensive milk (8.85 ± 0.57 g/L) than in semi-intensive milk (10.18 ± 0.2 g/L). Over the storage period, total protein levels decreased from 36 g/L to 30 g/L in extensive milk and 25g/L to 21g/L in semi-intensive milk. Fat content declined from 23g/L to 20g/L (extensive) and from 30g/L to 26g/L (semi-intensive). Lactose levels decreased from 47g/L to 37g/L (extensive) and from 37g/L to 33g/L (semi-intensive). Microbiological assessments indicated an increase in FAMT during storage, with milk from both systems peaking at day 22 before a slight decline. No coliforms were detected in any samples. However, both systems showed decreased pH, ash, protein, fat and lactose contents over the time. Effective breeding and collection practices management is essential to ensure camel milk’s optimal quality and safety.