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 gelidumsubsp. gasicomitatum 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 subsp. gasicomitatum 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.

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