Investigative study about the role of raw milk in transmission of some potentially pathogenic bacteria to humans in Behera governorate

Abstract EN

This study investigated the role of raw milk in transmission of Escherichia coli and Salmonella to humans in different districts of El-Behira Governorate during the period extended from November 2017 to October 2018.

A total of 240 raw milk samples (98 from dairy markets, 128 samples from dairy farms and 14 samples from retailers).

In addition, 50 stool specimens including; 37 from apparently healthy individuals and 13 from diarrheic patients were collected.

All samples were subjected to laboratory examination for isolation and identification of E.

coli and Salmonella by standard bacteriological methods.

It was found that the overall prevalence of E.

coli in milk samples was 18.3% (44/240) where the highest prevalence was recorded in samples collected from retailers (21.4%), followed by those obtained from dairy farms (20.3%) and lastly those gathered from dairy markets (15.3%) with non-significant association between the source of milk samples and the rate of isolation.

On the other hand, the overall prevalence of E.

coli in stool specimens was 34 % with higher prevalence in diarrheic patients (38.5%) compared to apparently healthy individuals (33.4%) with significant difference between them.

Serodiagnosis of 8 isolates of E.

coli represented to those recovered from milk samples clarified the presence of O111: H2 and O26: H11, O119: H6 and O121: H7 and O128: H2.

On the other side, serodiagnosis of 6 isolates of E.

coli represented to those recovered from stool specimens clarified the presence of O91: H21 and O26: H11, O17: H18, O128: H2 and O124.

Concerning Salmonella, it was recorded that the overall prevalence of Salmonella in milk samples was 0.4% (1/240) where only one sample obtained from retailers while its prevalence in stool specimens was 4.0 % with higher prevalence in diarrheic patients (15.4%) compared to apparently healthy individuals (0.0 %) where only 2 isolates were recovered from 50 examined samples with non-significant association.

Serodiagnosis of the three isolates of Salmonella recovered from milk and stool clarified the presence of S.

Infantis, S.

Typhimurium and S.

Enteritidis.

On conclusion, the recorded results throw the light upon the bacterial hazards that may be associated with consuming raw milk in El-Behera Governorate where investigated samples are found to be contaminated with Enteropathogenic E.

coli that could ring the hazard bell about cross contamination from human sources during handling and transportation.

Although the prevalence of Salmonella in the current work was very low, the role of raw milk in transmitting Salmonella must not be neglected and ongoing control programs must be adopted to exclude this hazard.