Scanning Probe Microscopy for polymer film characterization in food packaging

Scanning probe microscopy (SPM) is a branch of microscopy allowing characterization of surfaces at the micro-scale by means of a physical probe (with a size of a few microns) raster scanning the sample. SPMs monitor the interaction between such probe and the surface and, depending on the specific physical principles causing the interaction, they allow generation of a quantitative map of topographic properties: geometrical, optical, electrical, magnetic, etc. This is of the greatest interest, in particular whenever functional surfaces have to be characterized in a quantitative manner. The present paper discusses the different applications of Scanning Probe Microscopy techniques for a thorough characterization of polymer surfaces, of specific interest in particular for the case of food packaging applications

Physical properties and antimicrobial activity of bioactive film based on whey protein and Lactobacillus curvatus 54M16 producer of bacteriocins

The objective of the work was to study the viability and antimicrobial activity of bacteriocin-producing lactic acid bacteria (LAB) incorporated into whey protein/inulin/gelatine (WP) edible films in presence or absence of nutrient (modified MRS broth). Moreover, the role of the cell on the film structure and properties has been investigated. The results of the work showed that WP-based films were able to ensure a high viability of the bacteriocin-producing strain L. curvatus 54M16 during 28 days of storage at 4 °C. The addition of nutrient in the film matrix slightly affected the viability of the cells, but it was critical for the antimicrobial activity of the films. Films in presence of nutrient showed a good antimicrobial activity against L. innocua C6 as in vitro system as on cooked ham. The presence of LAB has a significant effect on the structure of the film: it reduced the viscosity of the film forming solution and improved the elasticity and the percentage of elongation. Whereas, no effect was observed for water vapour transmission rate and solubility. Thus, WP-based films in presence of modified MRS broth can be used as effective delivery and carrier systems for lactic acid bacteria to develop bioactive edible film or coating with antimicrobial properties

Animal rennets as sources of dairy lactic acid bacteria

The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions

Sono utili i Translation Studies per la pratica della traduzione?

The starting point for the present contribution is that professional translators as well as editors tend to consider the theoretical debate on translation with mistrust. By looking at the translation process in its various phases, this paper aims to demonstrate how theory does, as a matter of fact, provide a 'meta-language' that can be of great help in the training of prospective translators, while at the same time offering useful tools for an evaluation of the translated text that goes beyond a merely impressionistic critique, based on individual taste. Furthermore, this paper discusses a number of theoretical concepts developed in the field of translation theory that can be of use to the translator's analytical work before, during, and after his/her activity of transcodification

Atomic Force microscopy techniques to investigate activated food packaging materials

Since its invention, Atomic Force Microscopy has demonstrated to be one of the most interesting and useful techniques in many fields such as biology, optics and electronics to investigate nanoscale phenomena. Not only can it provide high resolution three-dimensional imaging of surfaces, but it also allows quantitative characterization of topographies, forces, mechanical and viscoelastic properties of interfaces at nanometer level. Scope and approach: Here we review current literature in the food packaging field where AFM has been proposed for the quantitative characterization of surfaces with functional layers allowing for exploitation of preservative properties as a result for example of higher permeability or antimicrobial activity. In fact, probing microscopes allow analysis of physical or mechanical properties of interfaces providing relevant information at the nanoscale with regard to different parameters such as dimensions, shapes, evolution and adhesion. Furthermore, recent developments in AFM have shown how fast imaging techniques can be implemented to allow time evolution description even at relatively high temperatures. What we aim is to establish how AFM is effectively promising in the research and development of innovative food packaging. Key findings and conclusions: AFM is largely used to characterize (bio)plastic materials for food packaging but also the comprehension of materials modification due to their activation is approached by using AFM, frequently combined to others instrumental analysis. In particular, even though AFM is basically used for topographical analysis of activated plastic materials, new and advanced AFM analysis are carried out for the characterization of different chemical and physical properties

Development of polythene films for food packaging activated with an antilisterial bacteriocin from Lactobacillus curvatus 32Y

Aims: The aims of this work were to (i) use a bacteriocin produced by Lactobacillus curvatus 32Y active against Listeria monocytogenes to activate polythene films by different methods, (ii) implement a large-scale process for antilisterial polythene films production and (iii) verify the efficacy of the developed films in inhibiting the growth of L. monocytogenes during the storage of meat products. Methods and Results: The film was made active by using the antilisterial bacteriocin 32Y by Lact. curvatus with three different procedures: soaking, spraying and coating. The antimicrobial activity of the activated films was tested in plate assays against the indicator strain L. monocytogenes V7. All the used procedures yielded active polythene films although the quality of the inhibition was different. The coating was therefore employed to develop active polythene films in an industrial plant. The antimicrobial activity of the industrially produced films was tested in experiments of food packaging involving pork steak and ground beef contaminated by L. monocytogenes V7 at roughly 10(3) CFU cm(-2) and gram respectively. The results of the challenge tests showed the highest antimicrobial activity after 24 h at 4degreesC, with a decrease of about 1 log of the L. monocytogenes population. Conclusions: Antimicrobial packaging can play an important role in reducing the risk of pathogen development, as well as extending the shelf life of foods. Significance and Impact of the Study: Studies of new food-grade bacteriocins as preservatives and development of suitable systems of bacteriocin treatment of plastic films for food packaging are important issues in applied microbiology and biotechnology, both for implementing and improving effective hurdle technologies for a better preservation of food products

rRNA-based monitoring of the microbiota involved in Fontina PDO cheese production in relation to different stages of cow lactation.

Fontina Protected Denomination of Origin (PDO) cheese is a full-fat semi-cooked cheese traditionally made in Northwest Italy (Aosta Valley) and manufactured from raw cow's milk. The management of cattle farms in Aosta Valley calls for seasonal migration to high pastures during the summer and the concentration of calving during the autumn and the beginning of the winter. Based on cattle physiology and given to calving seasonality, three cow lactation phases i.e. post-partum, oestrus and early gestation, can be identified and an effect could be hypothesized on average milk composition and on cheese quality.The aim of the present paper was to investigate the bacterial dynamics during Fontina PDO cheese manufacturing and ripening, in relation to the different lactation stages, in order to evaluate a possible correlation between microbiota and phase of lactation. For this purpose, microbial RNA analysis was carried out by RT-PCR coupled with DGGE and high-throughput sequencing. A good performance of the starter cultures was highlighted throughout Fontina PDO manufacturing and ripening; in fact, the starter prevailed against the autochthonous microbiota. Thus, the microbial activity, which was supposed to affect the final quality of Fontina PDO cheese, appeared to be strictly associated to the presence of the starter, which did not show any difference in its performance according to the different stages of cow lactation. Therefore, the results of this research highlighted a negligible correlation between the microbiota of raw milk and the organoleptic quality and typicity of Fontina cheese in relation to lactation seasonality