Pathogenic microorganisms, somatic cell count and drug residues evaluation in organic bovine milk

In last years increase the importance of milk quality and conditions of bovine milking. Simultaneously, increase the interest about organic milk and derivates. The aim of present study was investigate the milk pathogens, sensitivity and multiple drug resistance of isolates, somatic cell count and residues of drugs in milk, from cattle with and without mastitis, come from four little organic dairy farms in State of São Paulo, Brazil. Were used 148 cattle on the middle period of lactation. From these, two showed clinical mastitis, 72 subclinical mastitis and 74 without signs of mammary inflammation (controls). Staphylococcusaureus (25.7%), Streptococcus spp. (21.4%), Corynebacterium bovis (12.9%), Streptococcus agalactiae (4.3%) and Staphylococcus spp. (4.3%) were the more-frequent microorganisms isolated from animals with mastitis. Aspergillus spp. was isolated from one animal. Ceftiofur (95.2%), oxacillin (84.2%), gentamicin (76.3%) and cefoperazone (70.3%) were the more effective drugs. High resistance of isolates were found to penicillin (53.5%), ampicillin (41.6%) and neomycin (38.6%). Multiple drug resistance to three or more drugs was observed in 40 (39.6%) isolates. Media of somatic cell count encountered in animals with mastitis and controls were 175,742.67cs/mL and 58,227.6 cs/mL, respectively. Antimicrobials residues in milk were detected in four (2.7%) animals. The present findings showed the low somatic cell count of animals, indicative of good quality of milk. However, pointed the need of control measures for contagious pathogens of bovine mastitis and more attention for prohibition of antimicrobial use in organic dairy farms.

Organic milk; mastitis; bovine; somatic cell count; residues; multiresistance