Abstract

ASANZA, Sara Melissa Yupangui et al. Identification of Gram-positive Bacteria in raw milk samples obtained by manual milking. Rev. Inv. Cs. Agro. y Vet. [online]. 2024, vol.8, n.22, pp.69-83.  Epub Jan 20, 2024. ISSN 2664-0902.  https://doi.org/10.33996/revistaalfa.v8i22.249.

Cow's milk is one of the most consumed foods due to its abundant composition of proteins, fatty acids and essential micronutrients. However, these characteristics, combined with the poor hygienic measures in the method of obtaining this product through manual milking; as well as its collection, storage and transportation, make it susceptible to contamination by microorganisms and therefore responsible for gastrointestinal diseases. Objective. Identify Gram positive bacteria present in raw cow's milk, obtained by manual milking, from five dairy farms located in the Canton of Chilla in the Province of El Oro, in Ecuador. Materials and methods. By random sampling, 20 milk samples were obtained, each of 150 ml, collected from manual milking carried out in five dairy farms. Once the samples were collected, Regulation INEN1 529-2:99 was applied for handling and transportation. Likewise, a microbiological analysis was carried out according to the protocols of the NTE INEN9:2012 and NTE INEN 1529-5:2006 regulations, in the Microbiology and Parasitology Laboratory of the Technical University of Machala. For the detection and identification of Gram-positive bacteria, dilution, characterization, enzymatic biochemical test and Gram staining methods were applied. Results. The physicochemical characteristics of density and pH of the samples complied with the Regulations. In all the dairy farms, the presence of turbidity, gas and precipitate was observed in the 1/10, 1/100 and 1/1000 dilutions. Enzymatic tests and microbiological culture identified the presence of Staphylococcus aureus. Conclusions. The genus Staphylococcus species aureus was the predominant Gram positive bacteria.

Keywords : Microbiological analysis; Raw milk; Gram positive bacteria; Microbiological standards; Staphylococcus aureus.

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