Factors affecting the microbiological quality and contamination of farm bulk milk by Staphylococcus aureus in dairy farms in Asella, Ethiopia

Table 3 Univariable regression analysis of hygiene-related risk factors affecting TBC, CC, CPS and the occurrence of S. aureus in bulk farm milk

Variable	Category	No of farms (%)	p-value
Variable	Category	No of farms (%)	log₁₀ TBC	log₁₀ CC	log₁₀ CPS	Occurrence of S. aureus
Barn cleanliness	Clean	20 (40)	0.000	0.001	–	0.003
Barn cleanliness	Dirty	30 (60)
Cow cleanliness	Clean	20 (40)	0.000	0.001	–	0.003
Cow cleanliness	Dirty	30 (60)
Udder cleanliness	Clean	21 (42)	0.000	0.001	–	0.002
Udder cleanliness	Dirty	29 (58)
Milker’s hygiene	Clean	31 (62)	0.001	0.002	–	–
Milker’s hygiene	Dirty	19 (38)
Milk utensil hygiene	Clean	31 (62)	0.001	0.002	0.238	0.004
Milk utensil hygiene	Dirty	19 (38)
Water for milk utensils cleaning	Cold water	18 (36)	–	0.005	–	–
	Soap and cold water	11 (22)
	Hot water	5 (10)
	Soap and hot water	16 (32)
Smoking of milk utensils	Yes	36 (72)	0.241	–	0.214	–
Smoking of milk utensils	No	14 (28)
Water for teat and hand washing	Cold water	28 (56)	0.003	0.000	0.027	–
Water for teat and hand washing	Warm water	22 (44)

TBC Total bacterial count, CC Coliform count, CPS Coagulase-positive staphylococci count. Note: Linear regression was used when the outcome/dependent variable was continuous (bacterial count data), while logistic regression was used for categorical variables (S. aureus presence/absence). P ≤ 0.25 in the univariable regression analysis are shown in the table

ISSN: 1471-2180