Microbiological quality and somatic cell count in bulk of dromedary camels (Camelus dromedaius): Descriptive statistics, correlations, and factors of variation

Nagy Peter, Faye Bernard, Marko O., Thomas S., Wernery Ulrich, Juhasz Judit. 2013. Microbiological quality and somatic cell count in bulk of dromedary camels (Camelus dromedaius): Descriptive statistics, correlations, and factors of variation. Journal of Dairy Science, 96 (9) : 5625-5640.

Quartile : Q1, Sujet : AGRICULTURE, DAIRY & ANIMAL SCIENCE / Quartile : Q1, Sujet : FOOD SCIENCE & TECHNOLOGY

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : The objectives of the present study were to monitor the microbiological quality and somatic cell count (SCC) of bulk tank milk at the world's first large-scale camel dairy farm for a 2-yr period, to compare the results of 2 methods for the enumeration of SCC, to evaluate correlation among milk quality indicators, and to determine the effect of specific factors (year, season, stage of lactation, and level of production) on milk quality indicators. The study was conducted from January 2008 to January 2010. Total viable count (TVC), coliform count (CC), California Mastitis Test (CMT) score, and SCC were determined from daily bulk milk samples. Somatic cell count was measured by using a direct microscopic method and with an automatic cell counter. In addition, production parameters [total daily milk production (TDM, kg), number of milking camels (NMC), average milk per camel (AMC, kg)] and stage of lactation (average postpartum days, PPD) were recorded for each test day. A strong correlation (r = 0.33) was found between the 2 methods for SCC enumeration; however, values derived using the microscopic method were higher. The geometric means of SCC and TVC were 394 × 103 cells/mL and 5,157 cfu/mL during the observation period, respectively. Somatic cell count was >500 × 103 cells/mL on 14.6% (106/725) and TVC was >10 × 103 cfu/mL on 4.0% (30/742) of the test days. Both milk quality indicators had a distinct seasonal pattern. For log SCC, the mean was lowest in summer and highest in autumn. The seasonal pattern of log TVC was slightly different, with the lowest values being recorded during the spring. The monthly mean TVC pattern showed a clear difference between years. Coliform count was <10 cfu/mL in most of the samples (709/742, 95.6%). A positive correlation was found between log SCC and log TVC (r = 0.32), between log SCC and CMT score (r = 0.26), and between log TVC and CC in yr 1 (r = 0.30). All production parameters and stage of lactation showed strong seasonal variation. Log SCC was negatively correlated with TDM (r = ?0.35), AMC (r = ?0.37), and NMC (r = ?0.15) and positively correlated with PPD (r = 0.40). Log TVC had a negative correlation with AMC (r = ?0.40) but a positive correlation with NMC (r = 0.32), TDM (r = 0.16), and PPD (r = 0.45). The linear mixed model with stepwise variable selection showed that the main sources of log SCC variation were PPD, TDM, PPD × season, and season. For log TVC, the same factors and year contributed to the variation.

Mots-clés Agrovoc : lait de chamelle, qualité, microbiologie, analyse microbiologique, tank à lait, numération cellulaire somatique, variation saisonnière, durée de la lactation, dromadaire, Camelus dromedarius

Mots-clés géographiques Agrovoc : Émirats arabes unis

Classification Agris : Q03 - Contamination et toxicologie alimentaires
L50 - Physiologie et biochimie animales

Champ stratégique Cirad : Axe 3 (2005-2013) - Alimentation accessible et de qualité

Auteurs et affiliations

• Nagy Peter, Emirates Industries for Camel Milk and Products (ARE)
• Faye Bernard, CIRAD-ES-UMR SELMET (SAU)
• Marko O., Emirates Industries for Camel Milk and Products (ARE)
• Thomas S., Emirates Industries for Camel Milk and Products (ARE)
• Wernery Ulrich, Central Veterinary Research Laboratories (ARE)
• Juhasz Judit, Emirates Industries for Camel Milk and Products (ARE)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/570367/)

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