ABSTRACT
ABSTRACT Despite the increasing reports on the incidence of fresh vegetables and fruits as a possible vehicle for human pathogens, there is currently limited knowledge on the growth potential of Escherichia coli O157:H7 on different plant substrates. This study analyzed the selective adhesion and growth of E. coli O157:H7 on chili habanero (Capsicum chinense L.), cucumber (Cucumis sativus), radish (Raphanus sativus), tomato (Lycopersicon esculentum), beet (Beta vulgaris subsp. vulgaris), and onion (Allium cepa L.) under laboratory conditions. The Gompertz parameters were used to determine the growth kinetics. Scanning electron microscopy was used to visualize the adhesion of E. coli O157:H7 on the epicarp of the samples. Predictive models were constructed to compare the growth of E. coli O157:H7 on the samples with different intrinsic factors and to demonstrate the low selectivity of the pathogen. No significant difference was observed in the lag-phase duration (LPD), generation time (GT), and exponential growth rate (EGR) of the pathogen adhered to the samples. The interaction between the microorganism and the substrate was less supportive to the growth of E. coli O157:H7 for onion, whereas for tomato and cucumber, the time for the microorganism to attain the maximum growth rate (M) was significantly longer than that recorded for other samples.
Subject(s)
Vegetables/microbiology , Escherichia coli O157/growth & development , Fruit/microbiology , Capsicum/microbiology , Kinetics , Food Contamination/analysis , Solanum lycopersicum/microbiology , Cucumis sativus/microbiology , Escherichia coli O157/isolation & purification , Escherichia coli O157/genetics , Escherichia coli O157/chemistry , Onions/microbiology , Beta vulgaris/microbiologySubject(s)
Humans , Cucumis sativus/microbiology , Disease Outbreaks , Enterohemorrhagic Escherichia coli , Escherichia coli Infections/epidemiology , Food Contamination , Food Microbiology , Hemolytic-Uremic Syndrome/epidemiology , Global Health , Compensation and Redress , Conflict, Psychological , Enterohemorrhagic Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Escherichia coli Infections/transmission , Europe/epidemiology , European Union , Health Policy , Hemolytic-Uremic Syndrome/microbiology , Internationality , Latin America , SpainABSTRACT
Resistance of cucumber plantlets to culture filtrate of Fusarium oxysporum is correlated with resistance of single cells from callus. Single cells and platlets of two cultivars of cucumber were incubated with culture filtrates. Rapid cell death ocurred, as assessed by the stain fluorescein diacetate. More cell death ocurred in the cells of the cultivar Aodai than in to cells of the cultivar Caipira, which presented high level of resistance. Maximum toxic activity of culture filtrates was attained after 21-25 days of growth of the fungus.