Browsing by Author "Mauriello, Gianluigi"

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    Fate of Escherichia Coli O157:H7 and Salmonella Enterica in the Manure-Amended Soil-Plant Ecosystem of Fresh Vegetable Crops: A Review
    (Critical reviews in microbiology, 2015) Ongeng, Duncan; Geeraerd, Annemie Hellena; Springael, Dirk; Ryckeboer, Jaak; Muyanja, Charles; Mauriello, Gianluigi
    Enterohemorrhagic Escherichia coli (EHEC) and Salmonella enterica have been implicated in several disease outbreaks linked to consumption of fresh vegetables. Both ruminant and non-ruminant animals carry EHEC and S. enterica in their gastrointestinal tracts and can shed the pathogens in the faecal matter both in symptomatic and asymptomatic states. Application of animal waste in soil fertility management and irrigation of crops with contaminated waste water has been recognised as an important route through which EHEC and S. enterica can contaminate fresh vegetables during primary production. The behavior of E. coli O157:H7 and S. enterica in the agricultural environment has been extensively studied in the last decades. Several microbiological detection methods have been applied. This review therefore puts together current knowledge on the behavior of E. coli O157:H7 and S. enterica in the manure-amended soil-plant ecosystem of fresh vegetable crops during cultivation under various environmental conditions. The review focuses on methodological issues involved in undertaking survival studies and makes comparative analysis of experimental results obtained from studies conducted under controlled environmental conditions integrating results obtained from field experiments. Finally, a theoretical discussion on the potential likely impact of climate change on pre-harvest safety of field-cultivated vegetables is highlighted.
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    Microencapsulation by Vibrating Technology of the Probiotic Strain Lactobacillus Reuteri DSM 17938 to Enhance its Survival in Foods and in Gastrointestinal Environment
    (LWT-Food Science and Technology, 2015) Prisco, Annachiara De; Maresca, Diamante; Ongeng, Duncan; Mauriello, Gianluigi
    The probiotic strain Lactobacillus reuteri DSM 17938 was microencapsulated in alginate (MC) and in chitosan-alginate (CMC) matrix by vibrating technology with the main purpose to improve its tolerance to adverse environments. Microencapsulation procedure proved to not affect cell viability as indicated by a high encapsulation yield (97%) as well as further chitosan coating that minimally affected cell population. The viability of microencapsulated probiotic was evaluated under several stress conditions such as 28 days storage in different solutions at 4 and 20 °C, simulated gastrointestinal passage and osmotic stress conditions. Also reuterin production and diffusion through microcapsules were assessed. Results of survival assays showed that in most of tested conditions microencapsulation significantly (P < 0.05) improved L. reuteri DSM 17938 resistance. Furthermore, microcapsules were freeze dried in skimmed milk and no significant variations in cell viability and microcapsules morphology were observed. Morphological analysis revealed some differences between MC and CMC although both microcapsules had a diameter of 110 ± 5 μm, a spherical shape and a uniform and continuous surface. This study proved that microencapsulation by n chitosan-alginate matrix could improve tolerance of L. reuteri DSM 17938 towards stress conditions encountered in food processing as well as preserve its functional properties.
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    Modeling the Fate of Escherichia coli O157:H7 and Salmonella enterica in the Agricultural Environment: Current Perspective
    (Journal of food science, 2014) Ongeng, Duncan; Haberbeck, Leticia U.; Mauriello, Gianluigi; Ryckeboer, Jaak; Springael, Dirk; Geeraerd, Annemie H.
    The significance of fresh vegetable consumption on human nutrition and health is well recognized. Human infections with Escherichia coli O157:H7 and Salmonella enterica linked to fresh vegetable consumption have become a serious public health problem inflicting a heavy economic burden. The use of contaminated livestock wastes such as manure and manure slurry in crop production is believed to be one of the principal routes of fresh vegetable contamination with E. coli O157:H7 and S. enterica at preharvest stage because both ruminant and nonruminant livestock are known carriers of E. coli O157:H7 and S. enterica in the environment. A number of challenge-testing studies have examined the fate of E. coli O157:H7 and S. enterica in the agricultural environment with the view of designing strategies for controlling vegetable contamination preharvest. In this review, we examined the mathematical modeling approaches that have been used to study the behavior of E. coli O157:H7 and S. enterica in the manure, manure-amended soil, and in manure-amended soil–plant ecosystem during cultivation of fresh vegetable crops. We focused on how the models have been applied to fit survivor curves, predict survival, and assess the risk of vegetable contamination preharvest. The inadequacies of the current modeling approaches are discussed and suggestions for improvements to enhance the applicability of the models as decision tools to control E. coli O157:H7 and S. enterica contamination of fresh vegetables during primary production are presented.