Safety Issues Regarding the Detection of Antibiotics Residues, Microbial Indicators and Somatic Cell Counts in Ewes’ and Goats’ Milk Reared in Two Different Farming Systems

Georgios Rozos,Anastasios Tsinas,Eugenia Bezirtzoglou,Ioannis Skoufos,Chrysoula (Chrysa) Voidarou,Athina Tzora,Athanasios Alexopoulos,Konstantina Fotou

doi:10.3390/app12031009

Georgios Rozos, Anastasios Tsinas + Show 6 more

Open Access

https://doi.org/10.3390/app12031009

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Abstract

Milk samples of ewes’ and goats’ unprocessed milk were collected from milk tanks from various farms in Epirus, Greece and classified in two groups according to the type of farming. Analyses of the samples included microbial inhibition assays to detect the presence of antibiotic residues, isolation of Staphylococcus aureus and Escherichia coli strains as microbiological indicators for susceptibility to antimicrobial medicines, Somatic Cells and Coagulase Negative Staphylococci (CNS) counts. These findings were correlated with each other as well as to the stage of the lactation period and to the type of the farming practices. Monitoring of bulk tank milk for residues of antibiotics should be performed after heating of the milk, on a regular basis, and should include at least two different tests. The results point out that the type of farming affects the CNS counts as well as the prevalence of residues in the milk. Furthermore, the inverse correlation between CNS counts and prevalence of residues of antibiotics suggests a possible protective role of CNS. Resistance of the bacterial indicators to antibiotics was random and relatively rare, perhaps acquired in past due to misuse of antibiotics, turning the indicator microorganisms to reservoir of resistance.

Highlights

In the past, sheep and goat farming has been considered as an “inferior” form of animal husbandry and a sign of economic underdevelopment
The bulk tank milk should be monitored on a regular basis for residues of antibiotics
The monitoring process should include at least two different types of tests and should be performed after heating the milk samples to avoid false positive tests; It seems that the type of small ruminant farming practice affects the Coagulase Negative Staphylococci (CNS) counts in the bulk tank milk

Summary

Introduction

Sheep and goat farming has been considered as an “inferior” form of animal husbandry and a sign of economic underdevelopment. This was especially true for the Mediterranean countries. In mountainous and remote areas many farms still function in a traditional manner and a phenomenon of two-speed farming has been observed ([11] & personal data). The impact of this differentiation on various parameters that determine the quality and the safety of the milk has not been thoroughly investigated. There is a consensus in scientific literature that the Coagulase Negative Staphylococci (CNS) are among the main causative agents of subclinical mastitis in small ruminants and account for more than 65% of cases [13,14]

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