Abstract:
The study evaluated the effect of the hygienic, operational and
environmental conditions on the quality of raw milk produced and
consumed in Khartoum State in summer, and winter seasons, different
levels of collection centers (CC) (farms or dika), collection points (CP)
(markets or Sougs) and the milk delivered from the neighborhood states
(Gazira State GM).
To achieve these objectives, direct farm survey was conducted to
cover 300 farms distributed in seven Localities in Khartoum State. , Data
were collected and analyzed. The survey results showed that the sheds
construction was poor and non– hygienic, no clear water was available
for drinking and / or washing. Poor farm management, animals manure
was not uniformly removed which negatively affected the animal health
since they eat and sleep on a wet floor covered with the manure, some
grass stems and /or dirt were seen floating in the raw milk.
Four hundred ninteen four milk samples were collected from the
farm collection centre (CC) collection points (cp) and Gazera milk in the
mornings and at evenings, in summer as well as winter.
Physical properties tests have been conducted at the collection
points to determine the color, flavor and the density. The results showed
different in color due to some blood drops and showed a lot of dirt settled
and/or floating in the milk.
Regarding the densities results, when using the Lactometer
although 91% of the samples were within the acceptable range of 0.1024
– 0.1033.
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The result of freezing point showed that, 77% of the raw milk
samples were within the acceptable limits of the freezing point range
(-0.518, -0.535). All collected samples were tested to determine the
compositional, physical & chemical properties and the bacterial changes
in the raw milk which are mostly results of some external factors such as
thermal affect, manpower and hygienic conditions.
The results showed that the bacterial count of equal or less than
9x104 cfu /ml in winter was 35.4% compared to 19.4%in summer. That
means although the acceptable range in winter is much higher than in
summer but the majority of the raw milk in the state was very much
below the acceptable European limits.
As for Coliform, 60.1% of the samples in summer and 76.9% in
winter satisfy the internationally limit of acceptance which should be less
than 100 cell/ml. This shows that the difference between winter and
summer was statistically significant. It was found that the Coli form
bacteria at the farm were significantly less than any other level.
55% of the colleted samples were found free of the Coagulase
positive Staphylococci. The samples that have exceeded the limits of 103
was found to be 16.5% in Khartoum State. Enterococci were found in
almost 35.7% of the tested samples with different counts ranges , but
still 81% of the samples in the state were within the acceptable count
limit if it is considered to be 100 cell/ml .
Using the SCC applying the European Union standards for less
than or equal 5x105 , the farm and individual cows milk within this limits
were found to be 43.6% in winter and 20.9 % in summer, the samples
were mainly in the range of equal to or less than 7.5x105 with significant
Differences between the counts in winter and summer.
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It was found that 74.7% of the samples were within 0.20 Titrable acidity.
In winter 80.9% were within this limit. Clear significant correlation at
0.01 levels was found between SCC, acidity and TBC. Direct but not
significant correlation between SCP and CPS was found.
To identify both Gram positive and negative isolates, the API Kits
were used. Most of the CPS isolates were Staphylococcus aureus, while
the majority of CNS was Staphylococcus epidermidis from bulk milk.
Most of the isolates of Streptococci were Streptococcus uberis about
25.3% in milk and 29.4% from milker’s hands swabs. Few isolates of
Corynebacterium were recovered, Corynebacterium Pseudotuberclosis
37.5% and Corynebacterium ulceran 29.2%. Regarding the Gram
negative isolates most of the isolates were E. coli, followed by
Enterobacter species specially Enterobacter cloacae from both milk and
milker’s hands.
The result showed that 37.2% of the tested samples, using MRT to
identify the reactors to bovine brucellosis, reacted positively. 33.8%
reacted positive when using ElISA on milk for the same samples. The
MRT sensitivity and specificity were calculated to be 78% and 83%
respectively.
Applying the Alcohol test, 14 % of the samples were failed. 86% of
these failed samples were clotted when applying the cloting test. The
average ranges of the bulk milk composition in the state were found to
be:-
• Protein 3.1- 3.3%,
• Lactose 4.1- 4.3%,
• Fat 3.1- 3.6%.