High hydrostatic pressure treatment for the assessment of quality in sliced skin-packaged cooked and cured hams

In this study, a pressure of 600 Mpa was applied to sliced skin-packaged cooked ham and cured hams. Different lots were spiked with different food pathogens and spoiling microorganisms: slime-producing lactic acid bacteria (LAB), Staphylococcus aureus, Listeria monocytogenes, Yersinia enterocolitica, Escherichia coli, Salmonella spp., Campylobacter jejuni and Debaryomyces hansenii and compared to non-spiked samples. All samples were treated at high pressures and compared to parallel treatments non pressurized. Samples were stored up to 120 days at 4C and periodically analyzed

Antimicrobial activity of an edible film incorporated with oregano essential oil

info:eu-repo/semantics/publishedVersio

Antibacterial effects of peppermint, \u3ci\u3eMentha piperita\u3c/i\u3e essential oil in free-form and in nanoparticles on \u3ci\u3ePseudomonas fluorescens\u3c/i\u3e

Mentha piperita, commonly known as peppermint originally came from Europe and the Middle East and its oil is commonly used in traditional medicine and aromatherapy. Like many other free essential oils (EO), peppermint oil is believed to possess antimicrobial properties. However, the application of EO in food as an antimicrobial agent has yet to be established. This would require proper formulation of the EO for it to be viable in foods. This study aims to test the effects of both free Mentha piperita EO and Mentha piperita EO nanoparticles against Pseudomonas fluorescens and compare their inhibitory effects. We used nanoparticles of encapsulated Mentha piperita EO in a shell of fully hydrogenated soybean oil (FHSO) and expect that the inhibitory effects of these nanoparticles would be greater than that of the free EO due to the ability of the shell to protect the EO and control its dispersion. We observed for the presence of antibacterial properties using various methods such as well diffusion, disc diffusion, optical density measurements and plate counting of serial dilutions. We found that the best method that produced quantifiable results was to perform serial dilutions and plate count them after incubation. In these series of experiments, we demonstrated that free Mentha piperita EO inhibits P. fluorescens growth but have yet to demonstrate a similar effect with the EO nanoparticles

Antibacterial effects of peppermint, \u3ci\u3eMentha piperita\u3c/i\u3e essential oil in free-form and in nanoparticles on \u3ci\u3ePseudomonas fluorescens\u3c/i\u3e

Mentha piperita, commonly known as peppermint originally came from Europe and the Middle East and its oil is commonly used in traditional medicine and aromatherapy. Like many other free essential oils (EO), peppermint oil is believed to possess antimicrobial properties. However, the application of EO in food as an antimicrobial agent has yet to be established. This would require proper formulation of the EO for it to be viable in foods. This study aims to test the effects of both free Mentha piperita EO and Mentha piperita EO nanoparticles against Pseudomonas fluorescens and compare their inhibitory effects. We used nanoparticles of encapsulated Mentha piperita EO in a shell of fully hydrogenated soybean oil (FHSO) and expect that the inhibitory effects of these nanoparticles would be greater than that of the free EO due to the ability of the shell to protect the EO and control its dispersion. We observed for the presence of antibacterial properties using various methods such as well diffusion, disc diffusion, optical density measurements and plate counting of serial dilutions. We found that the best method that produced quantifiable results was to perform serial dilutions and plate count them after incubation. In these series of experiments, we demonstrated that free Mentha piperita EO inhibits P. fluorescens growth but have yet to demonstrate a similar effect with the EO nanoparticles

Modelling microbial inactivation kinetics under time-varying temperature conditions

The Gompertz model was applied for describing inactivation, assuming a typical pasteurisation temperature profile at food surface. In order to test the regression analysis procedure parameters were estimated on the basis of pseudo-experimental data. Results were compared to the ones obtained assuming processes at constant temperature. Care should be taken, if parameters estimated under isothermal conditions are going to be used for predicting inactivation under dynamic conditions

Gyümölcslevek romlását okozó savtűrő baktérium anyagcseretermékének kimutatása elektronikus orral = Detection of a metabolite produced by an acidophilic spoilage-causing bacteria by using electronic nose

Kísérleteink alkalmával egy obiigát aerob baktériumfaj, a gyümölcslé előállítók széles körében problémát jelentő termotoleráns és acidofil, főként alma- és narancslevek aroma elváltozását okozó, a hagyományos pasztőrözési eljárással szemben rezisztens, spórás Alicyclobacillus acidoterrestris által termelt anyagcseretermék kimutathatóságát vizsgáltuk. A gvajakol kimutatását legnagyobb részben egy NST 3320 (Applied Sensor Technology, Linköping, Svédország) típusú elektronikus orral végeztük, emellett azonban enzimes módszerrel (peroxidáz enzim által katalizált színreakciót eredményező, abszorbancia mérésen alapuló eljárás), SPME-GC-MS technikával (Agilent Technologies 5975 В VL kvadrupol töm egspektrom éter detektorral kiegészített Perichrom PR 2100-as típusú gázkromatográf), és érzékszervi vizsgálattal is összehasonlításokat végeztünk. Az elektronikus orr szenzor-jelválaszait többváltozós matematikastatisztikai módszerekkel (diszkriminancia-analízis, részleges legkisebb négyzetek módszere) dolgoztuk fel. Mérési eredm ényeink szerint, a szakirodalmi megállapításokkal összhangban, a gvajakolt almaléből legérzékenyebben a humán bírálók (detekciós határ: 1 ppm) tudták kimutatni, míg az SPM E-GC-M S technika (detekciós határ: 1-5 ppm) és az elektronikus orr (detekciós határ: 2-5 ppm) közel azonos szenzitivitással rendelkezett. Legkevésbé érzékenynek, így a gyakorlatban kevéssé alkalmazható eljárásnak az enzimes módszer (detekciós határ: 10-25 ppm) bizonyult. In this study, easy detection of an obligate aerobic, thermotolerant and acidophilic bacteria, the sporeforming Alicyclobacillus acidoterrestris was performed by determination of its specific metabolite, guaiacol. Since its spores have been shown to resist conventional pasteurization, it has become an important potential spoilage concern for fruit and vegetable juices, mainly for apple and orange juices. Detection of guaiacol was mostly carried out by using an NST 3320 (Applied Sensor Technology, Linköping, Sweden) electronic nose, but other methods, such as the peroxidase based enzymatic method with UV-Vis spectrophotometer, SPME-GC-MS technique (Perichrom PR 2100 gas chromatograph and Agilent Technologies 5975 В VL quadrupole mass spectrom eter) and an untrained sensory panel, were also applied. Results were analyzed in multivariate mathematicalstatistical ways. The results indicated, in agreement with other authors, that the sensory panel showed greatest sensitivity (detection limit: 1 ppm) to guaicol, whilst SPM E-GC-M S (detection limit: 1-5 ppm) and electronic nose technique (detection limit: 2-5 ppm) were not significantly different regarding sensitivity. Spectrophotometric method proved to be less sensitive to the problematic metabolite (detection limit: 10-25 ppm)