Thermoduric psychrotrophic proteolytic microbiota from refrigerated raw milk

Authors

  • Jose Carlos Ribeiro Junior Universidade Estadual de Londrina
  • Vanerli Beloti Universidade Estadual de Londrina
  • Fernanda Pelisson Massi Universidade Estadual de Londrina
  • Maria Helena Pelegrinelli Fungaro Universidade Estadual de Londrina

DOI:

https://doi.org/10.5433/1679-0359.2017v38n1p267

Keywords:

Bacillus pumilus, Cladosporium, Curvularia, Geotrichum, Proteolysis.

Abstract

Thermoduric microorganisms may withstand high temperatures during the pasteurization of milk. Therefore, the microbiota in pasteurized milk consist of thermoduric microbes and directly influence the shelf-life of the milk. The aim of this study was to identify thermoduric psychrotrophic proteolytic microbiota in refrigerated raw milk. Twenty samples, previously heat-treated, were streaked and incubated at 7°C for 10 days. The strains isolated were streaked on milk agar to assess proteolytic activity and were initially analyzed morphologically by light microscopy and then by molecular techniques to identify the species. In 40% of the samples analyzed was observed only one bacterial growth and others 10 thermoduric psychrotrophic fungi. All isolates were proteolytic. The sequencing of 16S rRNA gene identified the bacterial strain as Bacillus pumilus and analysis of the ITS1-5.8S-ITS2 region of fungal isolates revealed the Cladosporium cladosporioides (60%), Curvularia geniculatus (10%), and the 3 remaining strains were identified as Geotrichum candidum (30%). This is a fist description of B. pumilus in Brazilian raw milk. Considering the spoilage potential of all isolates and of the fungi present in raw milk and their survival in pasteurized milk, it is extremely important to carry out further studies to your resistant to heat, their impact on the shelf-life of pasteurized milk, ultra-high temperature (UHT) milk and dairy products.

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Author Biographies

Jose Carlos Ribeiro Junior, Universidade Estadual de Londrina

Discente do Curso de Doutorado do Programa de Pós-Graduação em Ciência Animal, Universidade Estadual de Londrina, UEL, Londrina, PR, Brasil.

Vanerli Beloti, Universidade Estadual de Londrina

Profª Drª, Departamento de Medicina Veterinária Preventiva, UEL, Londrina, PR, Brasil.

Fernanda Pelisson Massi, Universidade Estadual de Londrina

Discente do Curso de Doutorado do Programa de Pós-Graduação em Genética e Biologia Molecular, UEL, Londrina, PR, Brasil.

Maria Helena Pelegrinelli Fungaro, Universidade Estadual de Londrina

Profª Drª, Departamento de Biologia Geral, UEL, Londrina, PR, Brasil.

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Published

2017-03-02

How to Cite

Ribeiro Junior, J. C., Beloti, V., Massi, F. P., & Fungaro, M. H. P. (2017). Thermoduric psychrotrophic proteolytic microbiota from refrigerated raw milk. Semina: Ciências Agrárias, 38(1), 267–272. https://doi.org/10.5433/1679-0359.2017v38n1p267

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