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Microbiological characterization using combined culture dependent and independent approaches of Casizolu pasta filata cheese
Full text linkAims
Casizolu is a traditional Sardinian (Italy) pasta filata cheese made with cow raw milk belonging to Sardo-Modicana and/or Bruno-Sarda breeds added with natural whey starter. This work aims to describe the traditional technology of this product and to evaluate the microbial groups/species involved in the first month of ripening.
Methods and Results
Raw milk, curd after stretching and Casizolu cheese samples from two different farmsteads were subjected to enumeration of microbial groups, isolation and genotypic characterization of isolates and PCR temporal temperature gel electrophoresis (TTGE) analysis. The counts of lactobacilli and lactococci groups in raw milk were about 5–6 log UFC ml−1 of milk. These counts tended to increase in curd and cheeses, reaching values higher than 8 log UFC g−1 of cheese. Culture dependent and independent approaches employed in this work highlighted the fundamental role of Lactococcus lactis subsp. lactis, Streptococcus thermophilus and Lactobacillus paracasei in the manufacture and ripening of Casizolu cheese. Other species frequently isolated were Enterococcus durans, Enterococcus faecium, Enterococcus italicus while Enterococcus lactis, Streptococcus parauberis, Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus brevis, Lactobacillus fermentum and Lactococcus raffinolactis were isolated occasionally.
Conclusions
Lactococcus lactis subsp. lactis, Strep. thermophilus and Lact. paracasei were the principal bacterial species involved in the Casizolu cheese manufacturing and ripening. For the first time, Ent. italicus and Ent. lactis were isolated in the pasta filata cheese.
Significance and Impact of the Study
This study shows the first data on microbial groups and species involved in the manufacture of Casizolu cheese and highlights the role of Lact. paracasei and Enterococcus spp. from the earliest stages of ripening cheese; furthermore, provides evidence that raw milk cheese is a source of new strains and therefore a reservoir of microbial biodiversity.Aims: Casizolu is a traditional Sardinian (Italy) pasta filata cheese made with
cow raw milk belonging to Sardo-Modicana and/or Bruno-Sarda breeds added
with natural whey starter. This work aims to describe the traditional
technology of this product and to evaluate the microbial groups/species
involved in the first month of ripening.
Methods and Results: Raw milk, curd after stretching and Casizolu cheese
samples from two different farmsteads were subjected to enumeration of
microbial groups, isolation and genotypic characterization of isolates and PCR
temporal temperature gel electrophoresis (TTGE) analysis. The counts of
lactobacilli and lactococci groups in raw milk were about 5–6 log UFC ml
1 of
milk. These counts tended to increase in curd and cheeses, reaching values
higher than 8 log UFC g
1 of cheese. Culture dependent and independent
approaches employed in this work highlighted the fundamental role of
Lactococcus lactis subsp. lactis, Streptococcus thermophilus and Lactobacillus
paracasei in the manufacture and ripening of Casizolu cheese. Other species
frequently isolated were Enterococcus durans, Enterococcus faecium, Enterococcus
italicus while Enterococcus lactis, Streptococcus parauberis, Lactobacillus
plantarum, Lactobacillus pentosus, Lactobacillus brevis, Lactobacillus fermentum
and Lactococcus raffinolactis were isolated occasionally.
Conclusions: Lactococcus lactis subsp. lactis, Strep. thermophilus and
Lact. paracasei were the principal bacterial species involved in the Casizolu
cheese manufacturing and ripening. For the first time, Ent. italicus and
Ent. lactis were isolated in the pasta filata cheese.
Significance and Impact of the Study: This study shows the first data on
microbial groups and species involved in the manufacture of Casizolu cheese
and highlights the role of Lact. paracasei and Enterococcus spp. from the earliest
stages of ripening cheese; furthermore, provides evidence that raw milk cheese
is a source of new strains and therefore a reservoir of microbial biodiversity
TECNOLOGIA E CONTROLLO MICROBIOLOGICO DELLA “MRECA”, ALIMENTO TRADIZIONALE A BASE DI MUGIL CEPHALUS. [Technological optimisation and microbiological control of “Mreca”: a Sardinian traditional food based on Mugil cephalus]
No full textLa Mreca, alimento a base di muggine ( è un prodotto
tradizionale della Sardegna, la cui preparazione
artigianale presenta la peculiarità di utilizzare l’arbusto
Halimione portulacoides (L.) Aellen come involucro per
conservare i muggini dopo bollitura. La Mreca artigianale
non risulta conservabile a lungo. A questo scopo è stato
applicato un processo di trasformazione industriale che ha
tenuto conto sia dei parametri tradizionali, come l’impiego
del H. portulacoides sia di alcune azioni (trattamenti
termici adeguati) necessarie per l’ottenimento di un
prodotto sicuro.
Sui campioni di Mreca ottenuti con la tecnologia industriale
è stata valutata la presenza e l’evoluzione dei microrganismi
indicatori di igiene e di sicurezza verifi candone la shelf-life.
I risultati hanno mostrato l’idoneità della tecnologia
industriale proposta e l’effi cacia del trattamenti termici
eff ettuati sui muggini durante la preparazione della Mreca
che ne consentono un aumento signifi cativo della shelf
life. È stata, inoltre, evidenziata la necessità di ridurre
ulteriormente la carica batterica da parte della pianta in
quanto potenzialmente responsabile di ricontaminazione
durante il confezionamento e la conservazione.Mreca is a traditional food from Sardinia. It is made
with Mugil cephalus traditionally prepared by using the
Halimione portulacoides shrub as a casing during storage.
Mreca, thus produced, is storable only for a few days. For
this reason it has become mandatory to develop a new
industrial process to lengthen the shelf life of this product. In
this work, an industrial process transformation was applied
that took into account traditional parameters such as the
use of H. portulacoides and implemented new actions as
appropriate heat treatments and vacuum packaging. In all
industrial Mreca samples hygiene and safety parameters
were evaluated.
The results showed the eff ectiveness of the heat treatments
carried out on M. cephalus during the preparation of Mreca
and the potential recontamination by H. portulacoides
during the packaging and storage
Yeast biofilm in food realms: occurrence and control
No full textIn natural environments, microorganisms form microbial aggregates called biofilms able to adhere to a multitude of different surfaces. Yeasts make no exception to this rule, being able to form biofilms in a plethora of environmental niches. In food realms, yeast biofilms may cause major problems due to their alterative activities. In addition, yeast biofilms are tenacious structures difficult to eradicate or treat with the current arsenal of antifungal agents. Thus, much effort is being made to develop novel approaches to prevent and disrupt yeast biofilms, for example through the use of natural antimicrobials or small molecules with both inhibiting and dispersing properties. The aim of this review is to provide a synopsis of the most recent literature on yeast biofilms regarding: (i) biofilm formation mechanisms; (ii) occurrence in food and in food-related environments; and (iii) inhibition and dispersal using natural compounds, in particular
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
Effects of several commercial or pure lactic acid bacteria inoculants on fermentation and mycotoxin levels in high-moisture corn silage
Full text linkEffects of 3 commercial lactic acid bacteria (LAB) inoculants and 6 single strains of LAB on fermentation and levels of aflatoxins and other mycotoxins in high-moisture corn (HMC) silage were examined. Corn plants were inoculated with Aspergillus flavus at silk emergence and wet corn kernels were harvested at black layer stage (dry matter [DM]: 704 ± 5.0 g/kg). Samples were ground and ensiled directly (control group, CTR) or after treatment with one of the 9 LAB inoculants. The commercial inoculants contained Lentilactobacillus (Lent.) buchneri LB1819 and Lactococcus lactis O224 (SiloSolve FC; Chr. Hansen A/S, Hørsholm, Denmark), applied at a final dose of 250,000 CFU/g or 1,250,000 CFU/g (SiloSolve FC1x and SiloSolve FC5x, respectively); and Lent. buchneri and Lactiplantibacillus (Lac.) plantarum (Pioneer brand 11B91, Pioneer Hi-Bred International, Des Moines, USA) applied at a final dose of 250,000 CFU/g. One pure strain of Levilactobacillus (Lev.) brevis DSMZ 20054, two pure strains of Lac. plantarum (LP ATCC 8014 and LP PB) and three of Lacticaseibacillus (La.) rhamnosus (LR ATCC 7469, LR LR7 and LR RI) were also applied at a final expected dose of 250,000 CFU/g. Wet corn kernels were ensiled in 20 L mini-silos, compacted to a density of 389 kg DM/m3, and stored at room temperature. Conditions before ensiling were pH 5.87 ± 0.169, and (log10 CFU/g) of 7.68 ± 0.473 for LAB, 5.71 ± 0.121 for molds and 6.81 ± 0.341 for yeasts. The mini-silos were opened after 30 or 120 days. From day 30–120 days, levels of acetic acid, propionic acid and 1,2 propanediol increased (P < 0.05) in the SiloSolve FC1x, SiloSolveFC5x and Pioneer 11B91, and in LR LR7 groups. During this time, butyric acid level increased 5-fold in CTR; by two to three-fold in pure strains groups; and only slightly in the three commercial inoculants and the LR LR7 (P < 0.05). Aerobic stability increased (P < 0.05) with storage time from 32 to 97 h, and the commercial inoculants and LR LR7 groups had longer stability than CTR (P < 0.05). The storage time and the inoculants did not affect aflatoxin levels. No zearalenone or tenuazonic acid were detected in the mini-silos, even if they contaminated the corn plants. Results indicate that different silage inoculants affected fermentation of HMC and its contamination by mycotoxins, although no inoculant had an effect on levels of aflatoxins
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
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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