1,720,962 research outputs found
Effect of ionization technology on microbial contamination and food quality in food storage equipment
Full text linkIn this Ph.D. thesis ionization technology was studied from different points of view to investigate the possibility to use it inside domestic refrigerators to control microbial contamination during refrigerated storage without affecting the quality of the foods. Different concentrations of NAI and ozone were evaluated on food-related microorganisms belonging to different species: Gram-positive and Gram-negative bacteria, yeast, and mold. Ionization technology was effective in reducing the microbial counts of the selected species, achieving significant results for some peculiar spe-cies of interest in the food industry, like the pathogen Listeria monocytogenes and the typical food spoilage bacteria Pseudomonas fluorescens. These promising results led to the possibility to use this technology during cold storage for improving the hygienic status of the environment in which the food is stored. Therefore, the study of the effect of the same concentrations of NAI and ozone was carried out on fruits, vegetables, and mushrooms, showing that a high concentration of ozone was a critical factor since caused oxidation phenomena on foods and not satisfied the requirements for a safety and security exposition. Based on these findings, the use of NAI and a low concentration of ozone was studied in a simulation of real application inside a domestic refrigerator. The antimicrobial effect was investigated on different materials used for the realization of inner lines of refrigerators. Then, the effect was examined on lettuce, strawberries, and mushroom through a color vision system and physical analysis, demonstrating that the use of NAI under low concentration of ozone can improve the microbiological quality of the surrounding environment without affecting the quality of the foods.La tecnologia di ionizzazione è stata studiata da diversi punti di vista per indagare la possibilità di utilizzarla all'interno dei frigoriferi domestici per controllare la contaminazione microbica durante la conservazione refrigerata senza intaccare la qualità degli alimenti. Diverse concentrazioni di NAI e di ozono sono state valutate su microrganismi alimentari appartenenti a specie diverse: batteri Gram-positivi e Gram-negativi, lieviti e muffe. La tecnologia di ionizzazione è stata efficace nel ridurre la conta microbica delle specie selezionate, ottenendo risultati significativi per alcune specie peculiari di interesse nell'industria alimentare, come il patogeno Listeria monocytogenes e il tipico batterio del deterioramento degli alimenti Pseudomonas fluorescens. Questi risultati promettenti hanno portato alla possibilità di utilizzare questa tecnologia nei frigoriferi per migliorare lo stato igienico dell'ambiente in cui viene conservato il cibo. Pertanto, lo studio dell'effetto delle stesse concentrazioni di NAI e di ozono è stato effettuato su frutta, verdura e funghi, dimostrando che un'elevata concentrazione di ozono era un fattore critico in quanto provocava fenomeni di ossidazione sugli alimenti e non soddisfaceva i requisiti per sicurezza e esposizione di protezione. Sulla base di questi risultati, è stato studiato l'uso di NAI e una bassa concentrazione di ozono in una simulazione di applicazione reale all'interno di un frigorifero domestico. L'effetto antimicrobico è stato studiato su diversi materiali utilizzati per la realizzazione di linee interne di frigoriferi. Quindi, l'effetto è stato esaminato su lattuga, fragole e funghi attraverso un sistema di visione a colori e analisi fisiche, dimostrando che l'uso di NAI a bassa concentrazione di ozono può migliorare la qualità microbiologica dell'ambiente circostante senza influenzare la qualità del Alimenti
Effect of shape, gluten, and mastication effort on in vitro starch digestion and the predicted glycemic index of pasta
Full text linkGluten-containing (GC) and gluten-free (GF) pasta consumption has been growing in recent years. The market offers a wide variety of pasta types, with differences in shape and formulation that influence the mastication process and, consequently, their nutritional behaviors (i.e. starch digestibility and glycemic response). This study investigated the effect of shape, gluten, and structural breakdown on in vitro starch digestibility and predicted the glycemic index (pGI) of GC and GF penne, spaghetti, and risoni. Pasta was cooked and minced to mimic short, intermediate, and long mastication efforts. Short mastication led to a higher number of big particles than intermediate and long mastications for all pasta samples, which was reflected in the different starch digestibility and pGI patterns. Multivariate analysis of variance showed that the three studied factors differently affected the in vitro starch digestion of pasta. Mastication effort, shape, and their interaction mainly affected the starch digestion rate and pGI. Gluten was the major factor in affecting the amount of digested starch. The results suggested that small shapes (i.e. risoni), the presence of gluten, and short mastication effort led to a lower pGI. The findings will be useful for the development of pasta products tailored to fulfill the needs of specific consumers following a rational food design approach
Effect of negative air ionization technology on microbial reduction of food-related microorganisms
Full text linkNegative air ions (NAI) have been shown to have bactericidal effects on various microbial species. Different concentrations of NAI and ozone (106-7x106 NAI cm-3 s−1, 2.20 mg h-1 of ozone or 8 × 106-2x107 NAI cm−3 s−1, 0.02 mg h−1 of ozone, respectively) were studied to determine whether the effect of these treatments on six food-related microorganisms was due to NAI or also to the ozone that forms. Bacillus subtilis, Escherichia coli, and Listeria monocytogenes showed a significantly microbial reduction after the treatments of NAI with a low concentration of ozone, while Pseudomonas fluorescens, Penicillium roqueforti, and Saccharomyces cerevisiae were affected mainly by NAI and higher ozone concentration. It should be noticed that the reduction of the pathogen L. monocytogenes has been 2.17 Log after 72 h treatment to NAI and low ozone concentration. The results proved that ions (NAI) contribute to microbial killing. However, the sensitivity of microbial species is different and depends on individual parameters of the different microorganisms. NAI technology with low ozone production can be rapid, green, and low-cost and it can represent an alternative to the use of chemicals for the sanitation of air and surfaces in the food sector in order to reduce microbial contamination
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Inactivation of Foodborne Bacteria Biofilms by Aqueous and Gaseous Ozone
Full text linkIn this study, the efficacy of treatments with ozone in water and gaseous ozone
against attached cells and microbial biofilms of three foodborne species, Pseudomonas
fluorescens, Staphylococcus aureus, and Listeria monocytogenes, was investigated.
Biofilms formed on AISI 304 stainless steel coupons from a mixture of three strains
(one reference and two wild strains) of each microbial species were subjected to three
types of treatment for increasing times: (i) ozonized water (0.5 ppm) by immersion in
static condition, (ii) ozonized water under flow conditions, and (iii) gaseous ozone at
different concentrations (0.1–20 ppm). The Excel add-in GinaFit tool allowed to estimate
the survival curves of attached cells and microbial biofilms, highlighting that, regardless
of the treatment, the antimicrobial effect occurred in the first minutes of treatment,
while by increasing contact times probably the residual biofilm population acquired
greater resistance to ozonation. Treatment with aqueous ozone under static conditions
resulted in an estimated viability reduction of 1.61–2.14 Log CFU/cm2 after 20 min,
while reduction values were higher (3.26–5.23 Log CFU/cm2
) for biofilms treated in
dynamic conditions. S. aureus was the most sensitive species to aqueous ozone under
dynamic conditions. With regard to the use of gaseous ozone, at low concentrations
(up to 0.2 ppm), estimated inactivations of 2.01–2.46 Log CFU/cm2 were obtained after
60 min, while at the highest concentrations a complete inactivation (<10 CFU/cm2
) of
the biofilms of L. monocytogenes and the reduction of 5.51 and 4.72 Log CFU/cm2
of P. fluorescens and S. aureus respectively after 60 and 20 min were achieved.
Considering the results, ozone in water form might be used in daily sanitation protocols
at the end of the day or during process downtime, while gaseous ozone might be used
for the treatment of confined spaces for longer times (e.g., overnight) and in the absence
of personnel, to allow an eco-friendly control of microbial biofilms and consequently
reduce the risk of cross-contamination in the food industry
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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