Decarboxylase gene expression and cadaverine and putrescine production by Serratia proteamaculans in vitro and in beef

Francesca De Filippis, Carmela Pennacchia, Rosangela Di Pasqua, Alberto Fiore, Vincenzo Fogliano, Francesco Villani, Danilo Ercolini*

*Corresponding author for this work

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Studies of the molecular basis of microbial metabolic activities that are important for the changes in food quality are valuable in order to help in understanding the behavior of spoiling bacteria in food.

The growth of a psychrotrophic Serratia proteamaculans strain was monitored in vitro and in artificially inoculated raw beef. Two growth temperatures (25 °C and 4 °C) were tested in vitro, while growth at 15 °C and 4 °C was monitored in beef. During growth, the expression of inducible lysine and ornithine-decarboxylase genes was evaluated by quantitative reverse transcription-PCR (qRT-PCR), while the presence of cadaverine and putrescine was quantified by LC-ESI–MS/MS. The expression of the decarboxylase genes, and the consequent production of cadaverine and putrescine were shown to be influenced by the temperature, as well as by the complexity of the growth medium. Generally, the maximum gene expression and amine production took place during the exponential and early stationary phase, respectively. In addition, lower temperatures caused slower growth and gene downregulation. Higher amounts of cadaverine compared to putrescine were found during growth in beef with the highest concentrations corresponding to microbial loads of ca. 9 CFU/g. The differences found in gene expression evaluated in vitro and in beef suggested that such activities are more reliably investigated in situ in specific food matrices.

Original languageEnglish
Pages (from-to)332-338
Number of pages7
JournalInternational Journal of Food Microbiology
Volume165
Issue number3
Early online date3 Jun 2013
DOIs
Publication statusPublished - 1 Aug 2013
Externally publishedYes

Cite this