Spoilage potential of psychrotrophic lactic acid bacteria (LAB) species: Leuconostoc gelidum subsp. gasicomitatum and Lactococcus piscium, on sweet bell pepper (SBP) simulation medium under different gas compositions
Vasileios Pothakos, Clarice Nyambi, Bao-Yu Zhang, Antonios Papastergiadis, Bruno De Meulenaer,
LFMFP, Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Member of Food2Know, Coupure Links 653, B-9000 Ghent, Belgium.
Sweet bell peppers are a significant constituent of retail, chilled-stored and packaged food products like fresh salads, marinades and ready-to-eat (RTE) meals. Previously, through general screening of the Belgian market and by means of source tracking analysis in a plant manufacturing minimally processed, vegetable salads the susceptibility of fresh-cut sweet bell peppers to lactic acid bacterium (LAB) contamination was substantiated. The determination of the metabolic profiles of Leuconostoc gelidum
and Lactococcus piscium
, two major psychrotrophic, spoilage-related LAB species, on sweet bell pepper (SBP) simulation medium under different packaging conditions – 1.) vacuum: 100% N2
, 2.) air: 21% O2
, 79% N2
, 3.) MAP1
: 30% CO2
, 70% N2 and 4.) MAP2
: 50% O2
, 50% CO2
– facilitated a better understanding of the spoilage potential of these microbes as well as the presumptive contribution of O2
in the spectrum of produced volatile organic compounds (VOCs) associated with poor organoleptic properties of food products. Generally, none of the applied gas compositions inhibited the growth of the 4 L. gelidum
isolates, however the presence of O2
resulted in buttery off-odors by inducing primarily the accumulation of diacetyl and pungent “vinegar” smell due to acetic acid. The 3 tested isolates of L. piscium
varied greatly among their growth dynamics and inhibition at MAP2
. They exhibited either weak spoilage profile or very offensive metabolism confirming significant intraspecies diversity.
Keywoards: Psychrotrophic LAB; Spoilage potential; Leuconostoc gelidum subsp. gasicomitatum; Lactococcus piscium; SIFT-MS; Super-atmospheric oxygen.