Survival of foodborne pathogens in natural cracked olive brines

Food Microbiol. 2016 Oct:59:104-11. doi: 10.1016/j.fm.2016.05.017. Epub 2016 Jun 1.

Abstract

This work reports the survival (challenge tests) of foodborne pathogen species (Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica) in Aloreña de Málaga table olive brines. The inhibitions were fit using a log-linear model with tail implemented in GInaFIT excel software. The olive brine had a considerable inhibitory effect on the pathogens. The residual (final) populations (Fp) after 24 h was below detection limit (<1.30 log10 cfu/mL) for all species assayed. The maximum death rate (kmax) was 9.98, 51.37, 38.35 and 53.01 h(-1), while the time for 4 log10 reductions (4Dr) was 0.96, 0.36, 0.36 and 0.24 h for E. coli, S. aureus, L. monocytogenes and S. enterica, respectively. Brine dilutions increased Fp and 4Dr, while decreased kmax. A cluster analysis showed that E. coli had an overall quite different behaviour being the most resistant species, but the others bacteria behaved similarly, especially S. aureus and S. enterica. Partial Least Squares regression showed that the most influential phenols on microbial survival were EDA (dialdehydic form of decarboxymethyl elenolic acid), HyEDA (EDA linked to hydroxytyrosol), hydroxytyrosol 4-glucoside, tyrosol, and oleoside 11-methyl ester. Results confirm the adverse habitats of table olives for foodborne pathogenic microorganisms.

Keywords: Challenge tests; Food safety; Phenolic compounds; Survival models; Table olives.

MeSH terms

  • Escherichia coli O157 / drug effects
  • Escherichia coli O157 / growth & development
  • Escherichia coli O157 / pathogenicity
  • Fermentation
  • Food Microbiology*
  • Foodborne Diseases / prevention & control
  • Listeria monocytogenes / drug effects
  • Listeria monocytogenes / growth & development
  • Listeria monocytogenes / pathogenicity
  • Microbial Viability*
  • Olea / microbiology*
  • Phenols / pharmacology
  • Pyrans / pharmacology
  • Salmonella enterica / drug effects
  • Salmonella enterica / growth & development
  • Salmonella enterica / pathogenicity
  • Salts* / chemistry
  • Staphylococcus aureus / drug effects
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / pathogenicity

Substances

  • Phenols
  • Pyrans
  • Salts
  • brine
  • elenolic acid