Shelf life extension of ricotta cheese using coatings of galactomannans from nonconventional sources incorporating nisin against Listeria monocytogenes

J Agric Food Chem. 2010 Feb 10;58(3):1884-91. doi: 10.1021/jf902774z.

Abstract

Shelf life extension of Ricotta cheese was evaluated at 4 degrees C upon the use of edible coatings made of galactomannans from Gleditsia triacanthos incorporating nisin against Listeria monocytogenes. Three different treatments were tested in cheese: samples without coating; samples with coating without nisin; and samples with coating containing 50 IU x g(-1) of nisin. To test the effectiveness of the treatments against L. monocytogenes, the surface of the cheese was inoculated with a suspension of the microorganism. Microbiological and physical-chemical analyses of the cheese samples were performed during 28 days. Results showed that the cheese coated with nisin-added galactomannan film was the treatment presenting the best results in terms of microbial growth delay (p < 0.05). The addition of nisin also affects (p < 0.05) the physical and mechanical properties of the films: O(2) permeability decreased from 1.84 to 1.35 x 10(-12) cm(3) x (Pa x s x m)(-1); CO(2) permeability increased from 1.96 to 6.31 x 10(-12) cm(3).(Pa x s x m)(-1); opacity increased from 3.68 to 4.59%; tensile strength ranged from 0.84 to 1.46 MPa; and elongation at break improved from 50.93 to 68.16%. These results demonstrate that novel galactomannan-based edible coatings, when combined with nisin, may provide consumer-friendly alternatives to reduce L. monocytogenes postcontamination on cheese products during storage.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cheese / analysis*
  • Cheese / microbiology
  • Food Preservation / methods*
  • Food Preservatives / pharmacology*
  • Galactose / analogs & derivatives
  • Gleditsia / metabolism
  • Listeria monocytogenes / drug effects*
  • Listeria monocytogenes / growth & development
  • Mannans / metabolism
  • Mannans / pharmacology*
  • Nisin / pharmacology*

Substances

  • Food Preservatives
  • Mannans
  • galactomannan
  • Nisin
  • Galactose