Effect of milking routines and hygiene practices and evolution along the market value chain on raw camel milk quality in Tunisia

Figures & data

Table 1. Main characteristics of the studied camel farms.

Variables	Levels	%
Presence of male	Yes	87.5
	No	12.5
Management	Intensive	25
	Semi-intensive	62.5
	Extensive	12.5
Use of concentrate	Yes	75
	No	25
Veterinary control	Yes	100
Herd size		45.6 head
Size classes	<50 head	37.5%
	[50–100]	62.5%
Body condition	Average	37.5%
	Good	62.5%
Number of lactating camels		14.3
% lactating camels		36.5%
Number of milked camels		8.5
% milked camels/lactating		61.4
Lactation duration (month)		10.3

Table 2. Milking routine and hygiene in the studied camel farms.

Variables	Levels	%
Milking	Machine	12.5
	Hand	87.5
Milking frequency	Once	62.5
	Twice	37.5
Milker	One	50
	Multiple	50
Milker’s gender	Male	100
Milk ejection reflex induction	Oxytocin	12.5
	Tactile	37.5
	Calf	50.0
Udder massaging	Yes	75
Pre-rinse	Warm water	50
	Cold water	12.5
	None	37.5
Udder wiping	Yes	75
Use of iodine	Yes	25
Milking equipment cleaning	Before and after milking	87.5
	After milking	12.5
	Hot water + detergent	25
	Cold water + detergent	50
	Only water	25
	Acide– alkaline cleaning	12.5
Milking equipment material	Plastic	75
	Metallic	25
Milking location	Barn	25
	Bedded area	75
Milking location status	Clean	100
	Earth	1000
	Cement	0

Table 3. Milk storage at farm level in camel dairy farms.

Variables	Level	%
Milk storage	Milk tank (4–8 °C)	25
	Refrigerator (5 °C)	12.5
	Freezer (−18 °C)	62.5
	Ambient temperature	0
Storage duration	One day	12.5
	2 days	12.5
	More	50
	Immediate selling	25
Milk utilisation	Direct selling	62.5
	Direct selling + retailers	25
	Family consumption	12.5

Table 4. Effect of management and milking practice on milk yield.

	Stabling		Grazing
	Manual	Mechanical	Manual
Lactation stage (month)	4.4 ± 0.8	4.8 ± 1.4	2.5 ± 3.9
Separation time (h)	16 ± 0.0^a	15 ± 0.0^b	11.5 ± 1.2^c
Milk yield (L)	1.4 ± 0.6^c	3.3 ± 0.9^a	2.1 ± 0.6^b
Estimated Daily production (L/d)	4.2 ± 1.7	4.8 ± 1.7	4.3 ± 1.0

^a,b,cMeans in the same line with a different superscript letter are significantly different (p < 0.05).

Table 5. Effect of management and milking practice on milk quality.

	Stabling		Grazing
	Mechanical	Manual	Manual
Dry matter (g/L)	101.1 ± 10.8	103.4 ± 8.9	104.8 ± 13.8
Fat (g/L)	22.1 ± 4.6^a	15.9 ± 3.3^b	20.3 ± 6.6^a
Protein (g/L)	29.4 ± 5.2^b	32.7 ± 4.7^b	35.5 ± 6.9^a
Ash (g/L)	6.6 ± 0.8^c	7.9 ± 0.6^b	9.0 ± 0.4^a
pH	6.4 ± 0.2^b	6.6 ± 0.1^a	6.6 ± 0.1^a
Acidity (°D)	17.0 ± 1.7^ab	17.8 ± 2.4^a	15.0 ± 1.9^b
Viscosity	2.7 ± 0.1	2.7 ± 0.2	2.7 ± 0.1

^a,b,cMeans in the same line with a different superscript letter are significantly different (p < 0.05).

Table 6. Microbial assessment and SCC of milk samples according to breeding system and milking practice.

	Stabling		Grazing
Bacterial load (10^4 cfu mL^-1)	Machine	Manual	Manual
MTAF	193.0 ± 111.2	49.2 ± 16.9	70.5 ± 41.1
T. Coli	25.2 ± 14.3^a	27.6 ± 10.2^a	4.3 ± 1.3^b
LAB	0.2 ± 0.0	0.6 ± 0.1	0.5 ± 0.2
Yeast and moulds	2.4 ± 0.3	1.7 ± 0.8	5.4 ± 1.4
S. aureus	72.5 ± 44.9^a	7.2 ± 0.7^b	0.1 ± 0.05^c
SCC (10^4 cell/mL)	15 ± 5^ab	7.5 ± 2.5^b	23.6 ± 3.4^a
S. aureus Prevalence	50 %	25 %	60 %
> AT* MTAF	50 %	0 %	10 %
> AT* Coliforms	50 %	25 %	60 %

MTAF: Mesophilic Total Aerobic Flores; T. Coli: Total Coliforms; LAB: Lactic Acid Bacteria; S. aureus: Staphylococcus aureus; AT*: Acceptability Threshold by INNORPI (2009).

^a,b,cMeans in the same line with a different superscript letter are significantly different (p < 0.05).

Table 7. Quality evolution along the milk chain.

Milk	Camel	Bucket	Sale point	p Value
DM (g/L)	102.7 ± 11.1	109.9 ± 9.9	109.2 ± 14.9	0.153
Fat (g/L)	19.3 ± 7.6^b	23.9 ± 3.3^ab	28.3 ± 10.3^a	0.007
Protein (g/L)	31.9 ± 6.0^b	29.9 ± 9.9^b	37.7 ± 4.5^a	0.03
Ash (g/L)	7.6 ± 1.2	8.0 ± 0.4	7.8 ± 1.1	0.731
pH	6.6 ± 0.1^a	6.6 ± 0.1^a	6.2 ± 0.3^b	<0.0001
Acidity (°D)	16.9 ± 2.1^b	16.5 ± 2.4^b	25.3 ± 2.4^a	<0.0001
Viscosity	2.7 ± 0.1^b	2.6 ± 0.2^b	3.0 ± 0.7^a	0.042
> AT acidity	20.00 %^b	14.29 %^b	66.67 %^a	0.012

^a,bMeans in the same line with a different superscript letter are significantly different (p < 0.05).

Figure 1. Microbial evolution at critical points along the market chain. TBC: total bacterial count; LAB: lactic acid bacteria; Staph.: Staphylococcus aureus.

Table 8. Prevelance of S. aureus and bacterial contamination in different sampling points.

Milk	Camel	Bucket	Sale point	p Value
S. aureus Prevalence	0 %	71.43 %	100 %	<0.0001
> AT MTAF	0 %	42.86 %	100 %	0.001
> AT Coliforms	36.36 %	100 %	100 %	0.011

MTAF: Mesophilic Total Aerobic Flores; S. aureus: Staphylococcus aureus; AT: Acceptability Threshold by INNORPI.

INNORPI 2009. Lait de chamelle cru pour transformation [Raw camel milk for transformation]. Registered Tunisian Standard NT 14.261(2009) by National Institute of Normalization and Industrial Property.

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Data availability statement

Datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.