High oxygen concentration in combination with elevated carbon dioxide to affect growth of fresh-cut produce micro-organisms
C. Van der Steen, F. Devlieghere, J. Debevere
ISHS Acta Horticulturae 599: 141-147.
2003
บทคัดย่อ
High oxygen atmospheres (&gr; 70 %) can be used as an alternative for the nowadays applied low O2/elevated CO2 modified atmosphere, to prolong shelf life of respiring fresh-cut vegetables and fruit. The effect of high oxygen atmosphere, applied alone or in combination with elevated CO2 concentrations, on the growth of spoilage micro-organisms (14 species) and pathogens (Listeria monocytogenes and Aeromonas caviae (HG4)), isolated from fresh-cut produce, has been studied. Of each species only one strain was considered, except for Candida lambica, from which 5 different strains were analyzed to check possible differences in sensitivity for high O2 concentrations between strains of the same species. Lag phase (l), maximum specific growth rate (µmax), initial count (N0) and maximum count (Nmax) were determined applying the Baranyi model. The maximum specific growth rate of G- spoilage bacteria was slightly reduced by high O2. Growth rate of the two tested pathogens was rather stimulated by high O2. Lactic acid bacteria were much more sensitive to high O2 concentrations, but no additive or synergistic effect was found when high O2 was combined with high CO2. In most of the cases, growth of yeast strains was strongly inhibited by high O2, and this effect was even more pronounced when applying 80 % O2 + 20 % CO2 (additive effect). only one strain of Candida lambica was not at all affected by high O2 concentrations and/or elevated CO2. Growth of Candida humicola and of another strain of Candida lambica was significantly stimulated by high O2. So although yeast are generally inhibited during storage experiments with fresh-cut produce under high O2 atmosphere, this inhibitory effect is not true for every individual yeast strain in in vitro experiments.