Presentation by F Shija, G Misinzo, H Nonga, LR Kurwijila, K Roesel and D Grace at the 14th international conference of the Association of Institutions for Tropical Veterinary Medicine (AITVM), Johannesburg, South Africa, 25-29 August 2013.

1. F Shija, G Misinzo, H Nonga, LR Kurwijila, K Roesel and D Grace
Presented at the 14th International Conference of the Association of Institutes for Tropical
Veterinary Medicine (AITVM)
Johannesburg, South Africa
25-29 August 2013

2. 
Food-borne diseases are a threat and are
responsible for 33-90% cases of mortality to
children

Bacterial milk contamination causes:
◦ Milk spoilage
◦ Milk-born zoonotic diseases

Up to 90% diary related diseases are due to
pathogenic bacteria from milk

3. 
Dairy industry in most African
countries is dominated by
unpasteurized milk and informal
markets

PCR is a technique which utilizes
primer sets to detect presence of
pathogens in a sample

4. 
Risks of milk safety hazards in informal market
are high and unknown in Tanzania

Previous studies have been on the specific risks
associated with pathogenic microbes along the
milk chain (e.g. Swai and Schoonman 2011;
Kaiza et al. 2011)

5. 
PCR detection of milk bacterial contaminants is
powerful, gives reliable information on
pathogens in milk

Results of the study will be used to improve food
safety throughout smallholder and informal milk
value chain in Tanzania

6. Main Objective:
To assess milk handling practices, bacterial contamination
and determine selected milk borne zoonotic pathogens
along the dairy value chain in Lushoto and Handeni
districts of Tanga region
Specific objectives:
1.
To assess the possible sources of microbial
contamination of milk from farm to consumer
2.
To establish total plate count of bacteria and coliforms
in milk from Lushoto and Handeni districts
3.
To establish the prevalence of Escherichia coli
O157:H7 and Brucella abortus in milk using polymerase
chain reaction

7. Study area: Tanga region of the North-eastern
part of Tanzania
Why Tanga?: Well coordinated dairy value chain
◦ Long history of smallholder dairy farming
organized under TDCU
◦ Well developed TFL, one of the biggest
supplier of processed milk in Tanzania
Study design
o A cross–sectional study

8. Study area

10. 
A total of 93 (65 farmers, 28 retailers) interviewed

A total of 166 milk samples from farmers,
vendors, restaurants/kiosks, collection centres
and consumers

11. Chains identified-Lushoto district
1.
2.
3.
4.
5.
6.
7.
8.
Farmer Consumer
Farmer Sub Col centre (no chilling )
CC(chilling)
Factory
Consumer
Farmer CC(chilling)
Factory
Consumer
Farmer
CC
Consumer
Farmer
CC
Restaurant/kiosk Consumer
Farmer
Selling point
Consumer
Farmer
Restaurant
Consumer
Farmer/Processor
Consumer

12. Chains identified – Handeni district
1. Farmer
Consumer
2. Farmer
Vendor
Consumer
3. Farmer
Vendor
Collection Centre
Factory
consumer
4. Farmer
Collection centre
consumer
5. Farmer
Vendor
Restaurant
Consumer

13. Escherichia coli O157:H7 (O157-3 and O157-4)
Brucella abortus (BRU P5 and BRU P8 )

14. Microbiological isolation, PCR and statistical
data analysis (stata IC 11)

15. General practices during milking storage and delivery
Variable
Sources of water
Milking practices
Containers
storage
used
for
Containers used for
delivery/transportation
Means of delivery
Category
Tap
Wells
Dams and/or streams
Cleaning animal shed before
milking
Wash hands before milking
Wash cow's teats before
milking
Wash hands after milking
wide necked aluminium vessel
milk Wide necked plastic vessel
Used water and oil bottles
Cooking pan "sufuria"
wide necked aluminum vessel
Wide necked plastick vessel
Used water and oil bottles
Cooking pan "sufuria"
Others e.g traditional pots
On foot
By bicycle
By motorcycle
No. (%) farmers
respondents
26 (40.0)
21 (32.3)
19 (29.3)
28 (43.1)
46 (70.7)
41 (63.1)
47 (72.3)
2 (03.1)
56 (86.1)
6 (09.2)
1 (01.5)
0 (0.0)
38 (58.5)
8 (12.3)
3 (4.6)
16 (24.6)
37 (56.9)
9 (13.8)
3 (4.6)

16. Milk marketing channels

17. Total plate counts and coliform plate counts for
milk actors in the chains
Variable
Observation
s
Mean
(log10
cfu/ml)
Std. Dev
(log10)
Min
Max
Total Plate Count
Farmers
21
5.3
5.4
3.3
5.8
Vendors
5
5.8
5.7
4.6
6.1
Restaurants
7
0
5.3
Farmers
22
4.8
4.9
2.5
5.5
Vendors
4
4.8
5.1
3.3
5.4
Restaurants
7
3.6
3.9
0
4.3
4.9
4.9
Coliform plate count

18. Detection of B. abortus by PCR using BRU P5 and BRU P8 primer pairs targeting
16S-23S gene at between 500 to 600 bp. Note that lane M is a molecular
weight marker while lanes A, C, D, E, F, G, H, J, K, M, O, P and Q are positive
amplicons whereas lane B, I, L and N are negative amplicons. R is a positive
control.
42% positive
600 bp
500 bp

19. Positive samples for B. abortus in Lushoto and
Handeni districts
Source of
milk samples
Lushoto (%)
Handeni (%)
Consumers
(2.2)
(9.5)
Restaurant
(4.4)
(4.8)
Farmers
(31.1)
(26.2)
Vendors
-
(7.1)
(37.8)
(47.6)
Total
Both districts (%)
(5.7)
(4.6)
(28.7)
(4.6)
(42.5)

20. Detection of E. coli using O157-3 and O157-4 primer pairs targeting hyla A
between at 356 bp. Note that lane M is a molecular weight marker, lane A to
K are negative amplicons while lane L is a positive control
M
600 bp
500 bp
A
B
C
D
E
F
G
H
I
J
K
L

21. 
Poor hygienic practices at milking and selling
places contributes to increase in
microorganisms

Lack of knowledge on zoonotic diseases and
their causes in farmers contributed to poor
unhygienic practices in milky activities

The prevalence of B. abortus suggests high
contamination rate- relates to findings by
Schoonman and Swai (2005)

22. 



Veterinary/extension services should be
provided to livestock farmers on proper animal
husbandry and control of diseases.
Responsible authorities must ensure that
existing regulations are instituted and where
possible there should be a mandatory screening
of milk before sales to the public.
Consumer practices such as milk boiling should
be further encouraged.
Further study to relate the findings with human
brucellosis in that area should be carried out.

23. 
The Federal Ministry for Economic Cooperation
and Development, Germany through the Safe
Food, Fair Food project

Sokoine University of Agriculture (SUA)

International Livestock Research Institute (ILRI)

AITVM