1,721,094 research outputs found
Use of lactatae at different pH for preservation of fresh sausages
No full textTraditional Italian fresh sausage was manufactured with 3 different formulations: no sodium lactate; 1.5% sodium lactate at pH 7.0; or 1.5% sodium lactate at pH 5.5. Sausages were packaged in trays with a gas permeable sealing film or modified atmosphere packaged (in an 80% O 2/20% N 2 atmosphere at a product:gas ratio of 1:3) with a gas-impermeable sealing film. All the packaged samples were stored at 6°C. Physicochemical properties (pH, a w, drip formation), microbiological quality (psychrotrophic bacteria, coliforms and lactic acid bacteria) and sensory properties were assessed after 3, 6 and 9 days of storage for the conventionally packaged samples and after 5, 10 and 15 days for the modified atmosphere packaged samples. Overall, sodium lactate reduced microbial growth and improved shelf life of fresh sausages; use of sodium lactate at pH 7.0 gave the best inhibition of microbial growth. pH had no significant effect on the action of sodium lactate on retention of sensory properties during storage. Modified atmosphere packaging gave better shelf life then conventional packaging, except for a slightly higher incidence of drip formation on the surface of the sausages
Microbiological aspects (processing and storage) of a fermented vegetable (brovada)
No full textBrovada is a product similar to sauerkraut, which is typical of the Friuli region of Italy, and produced by natural lactic fermentation of white turnips ( Brassica rapa subsp. rapa) in the presence of vinasse. In this study the development of lactic acid bacteria and yeast species was studied during fermentation of brovada and subsequent storage of the commercially packaged product at 12 1°C. Results showed that Lactobacillus and Pediococcus spp. were the predominant lactic acid bacteria, while Saccharomyces spp. were the predominant yeasts. Surface pasteurization of the plastic pouch packaging (80°C for 10 min) increased the shelf life of the commercial product
Selection and oenological characterization of Saccharomyces cerevisiae strains isolated from Tocai, Pinot and malvasia grapes and musts of the Collio area
No full textOne hundred and nineteen Saccharomyces cerevisiae strains were isolated from Pinot, Tocai and Malvasia grapes and musts of the Collio area. The Saccharomyces cerevisiae isolated were tested for their oenological characteristics production of ethanol, glycerol, acetic acid, ethyl acetate, higher alcohols and hydrogen sulphide in white must. Kariotypes of Saccharomyces cerevisiae were also studied. The production of glycerol, ethanol, acetic acid and ethyl acetate depended on the strains, as well as the production of hydrogen sulphide. Low levels of higher alcohols were produced by all the strains tested. From the profiles of kariotype, slight differences were noted in the region of II, XIV, and X chromosomes among the strains tested.
From the data obtained, the most of the Saccharomyces cerevisiae isolated had good oenological characteristics that can be used as starters for Pinot, Tocai and Malvasia wine production
Lactic acid fermentation of Brassica rapa: chemical and microbial evaluation of a typical Italian product (brovada)
No full textBrovada is an ancient traditional product from the northeast Italian region, included in any list of typical Italian products, which is obtained by natural fermentation of turnips (Brassica rapa). Turnips are cleaned and put in vats, alternating them with a layer of grape skins. Before covering the vat a mix of water and salt or water only is added. The vegetable fermentation is a spontaneous process caused by the microorganisms present on the various components (turnip and grape skins). A total 225 lactic acid bacteria (LAB) and 63 yeasts were isolated during this natural fermentation process. The main heterofermentative population was identified as Lactobacillus spp. while the major homofermentative LAB were Pediococcus spp., Candida spp. was the main yeast present. During the first 24 h of fermentation, the pH decreased rapidly to 3.7. At different steps of fermentation the headspace aroma compounds of brovada were analyzed by solid-phase-micro-extraction/gas chromatography/flame ionization detection to define the characteristic aroma profile of this particular product
Basse temperature per la distruzione delle Salmonelle nelle carni
No full textThe various types of meat can be contaminated by Salmonella spp.To determine an effective mean for reducing or destroying this bacterial group in meats, samples have been subjected to low temperature (-3°/-5°C). A total destruction of Salmonella spp. was obtained after 48-72 h
Nuove Tecniche Microbiologiche per i patogeni alimentari: EIA, Impedenza, DNA probes, PCR
No full textIndagine sulla presenza di coliformi ed Escherichia coli in latte crudo e formaggi molli prodotti in Friuli-Venezia Giulia
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