117,421 research outputs found
Use of bio-protective cultures to improve the shelf-life and the sensorial characteristics of commercial hamburgers
No full textThe use of mixtures of bio-protective cultures, like Lactobacillus sakei subsp. carnosus/L sakei + Staphylococcus xylosus (1/1 ratio), Lactococcus lactis spp. lactis/L sakei + S. xylosus (1/1 ratio), and L sakei subsp. carnosus/L. sakei + S. xylosus (1/2 ratio), inoculated in beef hamburger packaged in modified atmosphere and stored at 4 +/- 2 degrees C, determined a better microbiological and chemical-physical quality of the products. In particular, they inhibited the growth of Brochothrix thermosphacta resulting in no white slime on the products as well as they determined a low concentration of total volatile basic nitrogen (TVB-N). Moreover, the bio-protective cultures influenced the flavour and the odour of the hamburgers. For this reason, the shelf life of the products added with starter cultures could be extended up to 12 day
Valorizzazione delle carni ovi-caprine
No full textThe report seeks to address a possible way for the promotion of fresh sheepmeat and goatmeat in the European context, through the review of the state of the art of the European market, world market and certification systems such as protected geographical indications (PGI) and designations of protected origin (PDO). The processed sheepmeat and goatmeat products, which have a long tradition in regional kitchens, are also treated; their production is strictly seasonal and addressed to a local consumer, in this national panorama Pitina stands out, the only product to have obtained IGP
Robots in industrial applications: State of the art and current trends
No full textThis Chapter aims at analyzing the state of the art in industrial robotics, in terms of successful industrial applications, from the perspective of robotic manufacturers and system integrators. It is worth to note that some of the solutions presented hereafter as innovative may be well known among the scientific community. However, due to many reasons, they only recently reached the market.
The idea is to highlight the gap between recent research results and industrial applications to stimulate the technology transfer from academia to common practice.
Firstly, the current market of industrial robotics will be analyzed and future trends discussed, in term of number and type of installed robots as well as in term of available technology. At the beginning the paper presents official statistics updated to 2010. These statistics are derived from those collected by IFR (International Federation of Robotics) in cooperation with OECD and UNECE. The selected data describe the size of the market, the more consolidated applications and the new trends.
The second part of the chapter describes the robotic technology available on the market, in term of kinematical structure of the manipulators, programmability of robotized cells, and sensors to improve flexibility. The different robot typologies are reviewed with respect to the robot applications and commercially available models.
The topics are discussed with several references to standard and innovative applications highlighting where technology transfer and/or some degree of innovation is still necessary
Shelf-life evaluation of sliced cold-smoked rainbow trout (Oncorhynchus mykiss) under vacuum (PV) and modified atmosphere packaging (MAP)
No full textCold smoked trout (Oncorhynchus mykiss) is a traditional product from the San Daniele del Friuli area (Italy), usually packaged under vacuum, and its shelf life is 60 days. Aim of this study was to evaluate the influence of two different packaging systems (Vacuum packaging-VP and Modified atmosphere packaging-MAP) on the microbial, physico-chemical and sensorial changes of sliced cold smoked rainbow trout during storage. MAP packaged sample showed lower microbial loads than VP packaged sample throughout storage. Microbial count of VP packaged sample exceeded the limit of 6 log CFU/g after 60 days of storage. The total volatile base-nitrogen (TVB-N) values increased over time in both treatments, reaching values close to the limit of 40 mg N/100 g after 45 days. Also TBARS values did not were up to 10 nmol/g in both VP and MAP. The shelf life of 60 days seems to be too long, particularly for the VP samples. A panel composed of 12 nonprofessional assessors perceived significant differences in the sensorial characteristic of the samples, and concluded that the sensorial quality of MAP packaged products were better than the VP ones (P<0.05). © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey in cooperation with Japan International Cooperation Agency (JICA), Japan
IMPROVEMENT OF FOOD SAFETY AND MICROBIAL INTERACTIONS
No full textIn these studies, different approaches for the conservation of meat and fish products were deepened. The application of bioprotective cultures and the addition of organic salts were investigated, following the current trends of demanding mild technologies for food, in order to contrast the pathogenic and spoilage microorganisms without significant modifications of the sensorial quality of the products.
In the first study, the anti-listerial activity of L. sakei strains, isolated from salmon scraps, was observed evidencing the importance of the possibility to reduce the risk of food alteration in cold smoked salmon industry and to prevent the replication of L. monocytogenes using autochthonous microorganisms with a potential biopreservative action.
Moreover, in the second study, strains of Lactobacillus animalis and L. paracasei subsp. paracasei, never studied before for bioprotective purpose and characterized by limited knowledge regarding their antagonistic properties, showed promising antimicrobial activity in vitro. This action against a wide number of spoilage and pathogenic bacteria was detected both when the strains were used singularly and was more evident when they were applied as mixture (especially when L. paracasei subsp. paracasei was predominant). The antagonistic effect was due mainly to the competition for nutrients and to the production of organic acids (acetic and lactic) as combined effects.
In the third study, two multistrain mixtures (L. sakei mixture and especially L. curvatus mixture), obtained adding different strains isolated and identified from Argentine vacuum packed meat, showed a promising antimicrobial activity against a wide number of spoilage and pathogenic bacteria, highlighting that the antagonistic effect originates probably from the nutrient competitive exclusion and the possible production of metabolites such organic acids. Moreover, the addition of the two mixtures to sliced vacuum-packed beef determined a better microbial quality of meat as TVC, Enterobacteriaceae and Gram negative bacteria resulted lower if compared to control samples. In any case, if compared with in vitro results, a slighter effect was detected on beef samples; it was probably due to the different competitiveness of the cultures if applied to a complex substrate like meat and to the buffering capacity of meat.
The fourth study was focused on the application of organic acids and salts on non-prepacked hamburgers, as they are known to exert potential benefits in terms of bacterial inhibition and stabilization of sensory characteristics. The addition of mixtures containing sodium ascorbate, sodium citrate and sodium acetate was effective in microbial inhibition of non-prepacked beef hamburgers, especially when the highest acetate dose was used. An evident activity was found against Gram negative bacteria, which represent the most important microorganisms in determining the shelf-life of raw minced meat. This, associated with lower TVB-N values, resulted in an improvement in the hygienic quality of treated samples. These salts are now admitted only for “prepacked meat preparations” but the results evidenced the convenience for butchers to extend the use of these organic salts to non-prepacked minced meat preparations as an additional means to ensure product safety and shelf-life.
In conclusion, the two technologies tested in these studies resulted to be promising as an evident antimicrobial effect was confirmed, suggesting the possibility to apply these tools to extend the shelf-life of food
Shelf-life of sheep <i>arrosticini</i> packaged in protective atmosphere
No full textThe aim of this study was to evaluate the shelf-life of pre-packaged sheep arrosticini produced in a factory located in northern Italy. Samples were divided into two series and packaged in modified atmosphere with specific gas mixtures: conventional (C: 35% O2/15% CO2/50% N2) and experimental (E: 30% CO2/70% N2). All the samples were stored at 4°C for 10 days and subjected, after 5, 8 and 10 days (t5, t8, t10), to triplicate microbiological and chemical-physical (pH, total volatile basic nitrogen, thiobarbituric acid reactive substances) analyses. At the same time, the colorimetric analysis and a sensorial evaluation were carried out (pack tightness, presence of color or odor alterations), assigning a discrete score from 0 to 5. The samples showed initial total bacterial counts close to 5 Log CFU/g: these values gradually increased during storage, exceeding the threshold of 8 Log CFU/g in the C series; lower values were detected in the E series. A similar trend was highlighted for Enterobacteriaceae, with initial loads of about 3 Log CFU/g and an increase until t10, reaching values higher than 6 Log CFU/g in the C series and close to 5 Log CFU/g in the E series (P=0.002). E. coli also showed a similar trend, although with values approximately 1 Log lower than Enterobacteriaceae. Pseudomonas spp. showed initial counts close to 4.5 Log CFU/g, with a different increase in the C series (6.5 Log CFU/g at t10) and the E series (4.95 Log CFU/g) (P=0.006). The higher growth in the C series was also observed for lactic acid bacteria, with an increase from 3 to 5 Log CFU/g (3.8 Log CFU/g in the E series P=0.016). The other microbiological parameters showed very low counts and, in most cases undetectable counts (<2 Log CFU/g) for the entire period considered. The initial values obtained from the measurement of the colorimetric indices were within the norm for this type of product: however, starting from t5, lower values of red index and lightness in the E series were measured, with an evident greying of meat surface. The results of the sensory evaluation indicated that the product showed optimal sensorial characteristics up to 8 days of shelf-life in the C series, while the use of an oxygen-free atmosphere, despite having a moderate inhibiting effect on the microbial populations, has led to an early modification of the product (5 days of storage), due to the presence of superficial greyish areas. The microbiological characteristics of arrosticini strictly depend on the hygienic conditions of slaughtering and production; even in optimal situations, the product is particularly perishable, and requires careful management of storage temperatures and times, to maintain its quality characteristics
Vegetable food waste valorization to earthworms production : preliminary evaluation for strategic decision-support in rearing system
No full textUse of food grade acetic organic acid to prevent Listeria monocytogenes in mozzarella cheese
No full textObjective of the present study was to evaluate the ability of acetic acid to inhibit the growth of L. monocytogenes when added to artificial brine for mozzarella storage. L. monocytogenes inoculated in mozzarella packages were divided in ten series for the treatment with acetic acid at different concentrations: 6.25 mM (ac1), 12.49 mM (ac2), 18.375 mM (ac3), 24.98 mM (ac4), 49.96 mM (ac5), 75 mM (ac6), 99.92 mM (ac7), 133.2 mM (ac8) and 149.87 mM (ac9); moreover, a control series was prepared. All the samples were maintained at 8 ◦ C and analysed at t0 and after 2, 5 and 10 days in triplicate. When applied to brine, acetic acid resulted effective only when its concentration was above 24.98 mM (ac4): in this case no growth was recorded during the sampling sessions. ac1, ac2 and ac3 series, also showed a lower growth with final increases of 2.69, 1.50 and 1.02 Log CFU/g, respectively. With concentrations above 49.96 mM (ac5), counts were always below the detection limit. pH values showed the acidifying effect of treatment exerted. The lowest concentrations of acetic acid with anti- microbial effect did not have significant repercussion on the sensorial characteristics of mozzarella cheese
- …
