The effect of cold storage, time and the population of Pseudomonas species on milk lipolysis

• Published in: Grasas y aceites (Sevilla) Vol. 70; no. 2; pp. 300 - e300
• Main Authors: Pereira, F. A.B., Luiz, L. L., Bruzaroski, S. R., Poli-Frederico, R. C., Fagnani, R., Santana, E. H.W.
• Format: Journal Article
• Language: English
• Published: Consejo Superior de Investigaciones Científicas 01-04-2019
• Subjects: enzymatic activity; lipase; milk lipolysis; pseudomonas fluorescens; pseudomonas putida
• ISSN: 0017-3495; 1988-4214
• DOI: 10.3989/gya.0583181

The aim of this study was to evaluate the lipolytic index (LI) of Pseudomonas fluorescens and Pseudomonas putida (2, 5, 6 log CFU/mL) in milk during 96 h by the Lipo R method. The strains were isolated from refrigerated raw milk (30 °C, 48 h), and species were confirmed by PCR, inoculated in reconstituted whole milk, and stored at 2 °C, 4 °C, and 8 °C. The storage time (ST) and temperature were associated with LI of P. putida. The interaction among lipolysis, temperature, and ST occurs even with a low population of P. putida and these variables combined together contributed to about 77% of the free fatty acids (FFA) in milk. The ST, temperature, and population of P. fluorescens showed a significant effect on its LI, and the variables contributed to about 43% of FFA. LI was about 224% higher in milk with P. fluorescens than with P. putida. The reduc-tion in ST and milk temperature resulted in a decrease in lipid lysis and a lower index of FFA by P. putida and P. fluorescens, with P. fluorescens showing a higher lipolytic capacity.