Livestock Research for Rural Development 19 (12) 2007 Guide for preparation of papers LRRD News

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Effects of breeding and hygienic practices on raw cow milk quality in Tadla area, Morocco

A Afif, M Faid* and M Najimi

Equipe de Biologie Fonctionnelle et Pathologique, Département des Sciences de la vie, F.S.T de Béni-Mellal,
PO. Box: 523, 23000 Béni-Mellal. Morocco
*Département de Génie des Procédés et Technologie Alimentaire, Institut agronomique et vétérinaire Hassan II, Rabat, Morocco


The main objective of this study was to evaluate the bacteriological quality of raw cow milk produced in two cooperatives in Tadla area in Morocco. During two periods (mid-June to mid-August, mid-November to mid-January), the milk samples (100) were collected at two milk collection centers (cooperatives) from cooperative 1 (semi-public farm) and cooperative 2 (Irrigated area). Samples were analysed for standard plate count (SPC), total coliform (TC) and feacal coliform (FC), lactic acid bacteria, spoilage microorganisms (proteolytic, lipolytic) and some of the pathogenic bacteria (staphylococci, clostridium and salmonella).


Our study in the region of Tadla showed the presence of heterogeneity in bacterial contamination among the cooperatives analysed. Thus, it appears that cooperative 2 is the heavily contaminated one. Whereas the less contaminated ones belong to the semi-public farm (i.e. cooperative 1). Procedures of milking, transportation, milking manner and pre-storage conditions could constitute the major factors involved in the contamination in cooperatives. Finally, these data represent the first investigation regarding the microbiological characteristics of raw cow milk produced in Tadla area from Morocco.

Key words: cooperatives, microbiology, milking conditions, period effect


In Morocco, the dairy industry is undergoing many problems related to the quality standards which are very hard to meet. This is due particularly to the heterogeneity of raw milk’s compositions. Many factors would contribute to this phenomenon such as the geographical area, breeding, climate conditions, and nutritional factors (Coulon 1994). Indeed, in Morocco, the milk collection centers still have many problems concerning hygienic quality of raw milk received (Srairi et al 2005; El Mouktafi 1988). This is due to the high temperature recorded in some regions of the country accompanied by a deficient milk refrigeration system. Furthermore, the non respect of the sanitation during milking and the handling would constitute an additional deteriorating factor (Aumaitre 1999). Therefore, it seems necessary to study the effects of such parameters on the quality of raw milk in order to improve and monitore an acceptable milk quality and through these studies, new breeding techniques can be described and applied in Morocco for better quality production.


To our knowledge, there was no breeding program in Morocco to include milk composition as well as microbiological characteristics (Hamama and El Mouktafi 1990). Only disparate official milk recording data exist but were not able to give a complete scheme. An exhaustive study has been reported by Mennane et al (2007) concerned particularly the effect of feeding from domestic waste on hygienic quality of raw cow’s milk in a determined  region of Morocco. However, there is no detailed investigation concerning dairy production and its microbiological characteristics in other Moroccan regions. Until now, milk production and characterization are still at a premium and no data may exist to know really the situation. Thus, the main objective of this study is to investigate the microbiological characteristics of raw milk produced in two cooperatives of Tadla region (leading region in milk production in Morocco). These cooperatives follow differents manner of milking raw milk. All these findings have been evaluated during two different periods in the year, in attempt to assess whether temperature variations could influence significatly the microbiological composition of raw cow milk.


Material and methods 

Characteristics of the dairy cattle cooperatives

The present investigation was carried out in two cooperatives representing the two cooperatives in the region of Tadla:


The raw cow milk samples were collected from milk collection centers (cooperatives) during the following periods: between the end of June and mid-August (period 1), between mid-November and mid-January (period 2). Samples were collected in the early morning. 250 ml samples of raw milk were taken starting from the cooled tanks, in sterile bottles and were immediately transported in an appropriated icebox to the laboratory. The test sample selection is carried out during two days of each week for the indicated periods. cooperative 1 (semi-public farm) applied a mechanically milking, and cooperative 2 who those adherents follow the traditional methods of milking raw milk.

Microbiological determinations

Ten ml of each sample were blended in 90 ml of sterile water (0.1%) in a disinfected mincer (blender) to prepare the initial dilution (1/10).

Standard Plate Count (SPC)

Appropriate serial dilutions (up to 10-6) of the sample in distilled water were pour plated on standard plate count agar (PCA) (Difco Laboratory, USA). The plates were incubated at 30°C for 48 hours.


Staphylococci counts were determined by the pour-plate method. Appropriate dilutions up to 10-6 were plated on Mannitol Salt Agar (Difco, USA), the plates were incubated at 37 °C for 24 h. The small yellow colonies on the medium were counted and checked for Gram and catalase reactions. Catalase positive and gram positive colonies were spread cultured on trypticase soya agar slants for further characterization.


Coliforms were enumerated on Macconkey agar (Merck, Germany). The plates were incubated at 37°C for total coliforms (TC) and at 44°C for faecal coliforms (FC) for 24 hours. The appeared colonies on the medium were restreaked on the same medium for more purification. Isolated colonies were cultured on trypticase soya agar slants and incubated for 24 hours for further identification and cultures were stored at 4°C until identification.


25 g of the sample were added to 125 ml of sterile buffered peptone water and incubated for 18 hours at 37°C. Tree tubes of tetrathionate broth and 3 tubes of selenite-cystein broth (Difco, USA) were inoculated with 1 ml from cultures of buffered peptone water and incubated for 24 hours at 37°C. Positve tubes of both media were streaked on Hektoen agar (Difco, USA). The method described by Poelma et al (1984) was used for the identification.

Spore forming bacteria

The initial dilution was heat activated at 80°C for 10 min and immediately cooled in iced water. Anaerobic sulfite reducing Clostridium were groew on SPS medium (Merck, Germany) in tubes which  were  then inoculated  with  2, 1 and 0.5 ml of the heat activated dilution and incubated at 30°C for 24 hours.

Spoilage microorganisms

The appropriate dilutions up to 104 were plated on the medium milk contain. The plates were incubated at 30 °C for 48 to 72 h. After solidification, a clear halo around the colonies will be counted.


Dilutions up 10-6 were plated on Tween 80 medium. The plates were incubated at 30 °C for 48 to 72 h. Colonies of the lipolytic bacteria were  surrounded by an opaque halo due to the release of free fatty acids.

Lactic acid bacteria

The lactic acid bacteria were counted on MRS (De Man Rogosa and Sharpe) medium incubated at 30 °C for 48 h.

Statistical analysis

Data obtained from all microbological analysis were analysed by analysis of variance (ANOVA) and by the least significant difference (LSD) (SAS, proc glm).



To assess the diversity and influence of conditions of production on raw cow milk microflora, the microbial composition of 100 raw cow milk samples was determined. The results obtained were depicted in tables 1 and 2, which summarize the mean count of the seven bacterial groups analysed of locally produced raw milk collected from two cooperatives presenting different breeding and milking ways during period 1 (mid-June to mid-August) and period 2 (mid-November to mid-January) respectively.

Table 1.  Mean counts for all microbial groups in period 1






Staph   (103)

























Coop: cooperative; FC: faecal coliforms; TC: total coliforms; Staph: staphylococci;
SPC: standard plate counts; LAB: lactic acid bacteria; Proteo: proteolytic; Lipo: lipolytic.

a-b  each distinct letter indicates a different group as obtained by the analysis variance.
Means within columns without a common superscript are significantly different (P < 0.05).

Table 2.  Mean counts for all microbial groups in period 2






Staph   (103)

























Coop: cooperative; FC: faecal coliforms; TC: total coliforms; Staph: staphylococci;
SPC: standard plate counts; LAB: lactic acid bacteria; Proteo: proteolytic; Lipo: lipolytic.

a-b  each distinct letter indicates a different group as obtained by the analysis variance. Means within columns without a common superscript are significantly different (P < 0.05).

When the breeding and milking ways were considered, the variance analysis of our results of all microbial contamination showed that there is a significant difference between cooperatives 1 and 2. The least significant difference (LSD) mentioned the presence of two groups during periods 1 and 2 of cooperatives 1 and 2. Comparaison of results obtained in the two cooperatives, are presented in figures 1-7. As depicted by these figures, it appears clearly that cooperative 1 had the lowest levels of all bacteria. Considering FC, the significative difference (P < 0.05) is evidenced for the two periods analyzed (Figure 1).


Figure 1.  Effect of the period and the milking way in two different cooperatives (1 and 2)
on feacal coliform contamination in raw milk

Thus, the mean values of  FC were 2.48x103 and 4.63x104 fcu/ml in period 1 respectively of cooperatives 1 and 2 (Table 1) , whereas in period 2 the mean values were 1.98x102 and 5.91x104 fcu/ml (Table 2) respectively. Similarly, when the TC are considered, the average values were limited between 4x104 and 3.17x106 fcu/ml in period 1 but in period 2, the average values were ranged between 1.98x103 and 1.6x106 fcu/ml, respectively for cooperatives 1 and 2 (Figure 2).

Figure 2.
  Contamination of raw cow milk samples collected from two cooperatives (1 and 2)
located in Tadla region during two different periods. For each cooperative the bacterial load
(total coliform) is given as mean count

For the standard plate count (SPC) the difference was also significant in the two periods as the difference between the mean values of cooperatives 1 and 2 was higher in period 1 (figure 3): 1.63x106 and 2.13x107 fcu/ml and in period 1.63x106 and 9.68x106 fcu/ml respectively of cooperatives 1 and 2.

Figure 3.
 Mean count of bacterial load (standard plate count) of raw cow milk collected
 in cooperatives 1 and 2 calculated for the two periods analyzed i.e (mid-June to mid-August:
period 1 and mid-November to mid-January: period 2)

The bacterial loads differ also from the hottest period (period 1) to the cold one (period 2) for staphylococcus and lactic acid bacteria. Thus, in period 1 and 2, the results for staphylococcus aureus (Figure 4) evidenced the presence of a significant difference between the cooperatives 1 and 2.

Figure 4.
  Prevalence of pathogens (staphylococci) in raw cow milk
collected from local dairy cooperatives (1 and 2) in Tadla region in two different periods 

The mean values for staphylococcus aureus in period 1 were 1.06x103 and 1.13x104 fcu/ml (P < 0.05) and in period 2 : 6.57x102 and 1.93x103 fcu/ml (P < 0.05) respectively of cooperatives 1 and 2. Concerning lactic acid bacteria (LAB), tables 1 and 2 show that  a significant higher (P < 0.05) LAB count has been found in cooperative 2 when compared to cooperative 1. This difference is evidenced in the two periods analysed (Figure 5). 

Figure 5.
 Occurrence of lactic acid bacteria in the raw cow milk samples obtained from two milking cooperatives, in Tadla region. The mean count of cooperatives 1 and 2 is given for the two periods

For proteolytic (Figure 6) and lipolytic microorganisms (Figure 7), the analysis of variance shows that the difference is significant (P < 0.05) only for lipolytic microorganisms in two periods (Tables 1-2).

Figure 6.
  Presence of spoilage microorganisms (proteolytic) in raw cow milk. Note that in contrast to the other bacterial groups, the mean count of this group is significantly higher in cooperative 1 than in cooperative 2, both in period 1 and period 2


Figure 7.
  Spoilage microoraganisms (lipolytic microorganisms) mean count in 100 raw cow milk samples taken from two different cooperatives located in Tadla area. Note that the load is higher in cooperative 2 compared to cooperative 1 for each period 

Of note, salmonella and clostridium were not detected in raw milk samples collected from two cooperatives.



Taken together, the results showed a variability in raw cow’s milk quality between two cooperatives (1 and 2) during the periods of investigation (one cold and the other hot to very hot period). Concerning FC and TC levels in our study were lesser than the results reported in Gharb region (North of Morocco) by Ounine et al  (2004) and by Riahi (1981). The existence of coliform bacteria may not necessarily indicate a direct fecal contamination of milk, but more precisely as an indicator of poor hygiene and sanitay practices during milking and further handling. This could explain clearly the significant difference evidenced between the two cooperatives. Indeed, in cooperative 1, milking is made mechanically and the occurrence of fast refrigeration in this cooperative contributes further to the presence of lesser levels.


The standard plate count (SPC) is taken as an indicator concerning the hygienic conditions of the raw milk in collecting centers. In this sense, we note that the heavy contamination was found during the period 1 (i.e the hottest period). Furthermore,  the cooperative 1 contain the lowest levels of SPC compared to the cooperative 2. More contamination of raw milk in cooperative 2 is due to the low microbiological quality of the water used for cleaning utensils and animals, as well as milk storage conditions which would lead to a poor quality of milk in this cooperative (Chatelin and Richard 1981; Piton and Richard 1982). Our results in this study are in agreement with reports of Srairi et al (2005), Amhouri et al (1998) and Bonfoh et al (2003). Although diffrences in stphylococci loads were evidenced between cooperatives 1 and 2, they are still lower compared to the levels founded by Hamama (2002) in Rabat region. Staphylococci count reached an average of 103 cfu/ml in fresh milk samples. These levels are still insufficient to induce a risk of intoxication by staphylococci toxin production (Bergdoll 1970) and are still lower than the limits accepted in USA and EU for the raw cow milk. The fact that the smallholder adopt a traditional milking imply the presence of higher staphylococci loads. The presence of lactic acid bacteria in high numbers are undesirable in fresh cow milk  because of the acid production and coagulation which is a default in fresh milk. In our study, the levels of lactic acid bacteria were higher in cooperative 2 during the priod 1, corresponding to the hot months, so the raw milk quality under these condition favorise the increase of lactic acid bacteria load in raw milk.


Some lactic acid bacteria can also be sheltered to the udder surface according to Desmasures et al (1997) or generally, on the body of the cows (Salama et al 1995). Therefore a minimal hygiene around the udder would preserve this type of flora (Bacic et al 1968).


The results of proteolytic and lipolytic microorganisms showed that there is a significant difference in two period only for lipolytic microorganisms. The acidification of milk is related to the relative proportions of technological flora and spoilage flora of milks which are proteolytic and lipolytic microorganisms. In period 1, the significant difference was showed in cooperative 2 concerning lipolytic microorganism and was characterized by high level than cooperative 1, the same situation was observed in period 2. Taken together, the results obtained in the present data evidenced clearly the determined role of breeding way and practices in the quality of raw milk. This is of high importance, considering the fact that the major part of this milk is destined to be processed industrially as a pasteurized milk.



Amhouri F, Saidi B, Hamama A and Zahar M 1998 Qualité microbiologique du lait cru: Cas de la région d’Errachidia. Actes Institut Agronomique et Vétérinaire Hassan II 18: 31-35


Aumaitre A 1999 Quality and safety of animal products. Livestock Production Science 59: 113–124


Bacic B, Jackson H and Clegg L 1968 Distribution of bacteria in milk drawn directly from the cow’s udder.  Journal of Dairy Science 51: 47–49


Bergdoll M S 1970 Enteroxins in Montie T C, Kadis, S and Alj S, editors.  Microbial toxin Volume 3  New York  London


Bonfoh B, Wasem A, Traore A N, Fane A, Spillmann H, Simbe C F, Alfaroukh I O, Nicolet J, Farah Z and Zinsstag J 2003  Microbiological quality of cows’ milktak en at different intervals from the udder to the selling point in Bamako (Mali). Food Control 14 (7): 495–500


Chatelin Y and Richard J 1981 Etude de quelques cas de contaminations microbiennes importantes du lait à la ferme. Lait 61: 80–94


Coulon J B 1994 Influence des facteurs nutritionnels sur le taux protéique du lait. Recueil de Médecine vétérinaire 170 (6/7): 375-380


Desmasures N, Opportune W and Guéguen M 1997 Lactococcus spp., yeasts and Pseudomonas spp. on teats and udders of milking cows as potential sources of milk contamination. International Dairy Journal 7: 643–646


El Mouktafi M 1988 Etude bactériologique du lait cru de mélange. Thèse de doctorat vétérinaire. Institut Agronomique et Vétérinaire Hassan II, Rabat, Morocco


Hamama A and El Mouktafi M 1990 Etude de la qualité hygiénique du lait cru produit au Maroc. Maghreb Vétérinaire 5: 17-79


Hamama A 2002 Cours de formation des techniciens de l’Office Régional de Mise en Valeur Agricole du Haouz. Rabat Morocco


Mennane Z, Ouhssine M, Khedid K and EL Yachioui M 2007 Hygienic quality of raw cow’s milk feeding from domestic waste in tow regions in Morocco. International Journal of Agriculture and biology 9: 46-48.


Ounine K, Rhoutaisse A and  El Haloui N E 2004 Caractérisation bactériologique du lait cru produit dans les étables de la région du Gharb. Al awamia 109-110, 187-204


Piton C and Richard J 1982 Causes de contamination microbienne d’importance moyenne du lait dans un groupe de fermes de la région de Rennes. Lait  62: 67–74


Poelma  P L, Andrews W H and Silliker J H  1984 Salmonella. In: Compendium of Methods for the Microbiological Examination of Foods (American Public Health Association), 2a ed., Washington, DC: Marvin L. Speck, p. 286-320.


Riahi N 1981 Contribution à l’étude de la qualité bactériologique des centres de collecte dans la région du Gharb. Thèse pour le doctorat vétérinaire. Institut Agronomique et Vétérinaire Hassan II Rabat, Morocco


Salama M S, Masafija-Jeknic T, Sandine W E and Giovannoni S J 1995 An ecological study of lactic acid bacteria : isolation of new strains of Lactococcus including Lactococcus lactis subsp. Cremoris. Journal of Dairy Science 78: 1004–1017


Srairi M T, Hasni Alaoui I, Hamama A and Faye B 2005 Relations entre pratiques d’élevage et qualité globale du lait de vache en étables suburbaines au Maroc. Revue de Médecine Vétérinaire 156 (3): 155-162 

Received 4 July 2007; Accepted 13 September 2007; Published 11 December 2007

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