Raman spektroskopisinin üç önemli gıda kaynaklı patojenin karakterizasyonunda uygulanabilirliği

Hızlı, düşük maliyetli ve örnek üzerinde tahribat yapmayan özelliklerinden dolayı Raman spektroskopisi mikroorganizmaların saptanmasında ve tanımlanmasında son zamanlarda yararlı bir metot olarak kullanılabileceği bildirilmiştir. Bu çalışmada, üç adet çok önemli gıda kaynaklı patojen olan Escherichia coli, Salmonella Typhimurium ve Staphylococcus aureus'un Raman spectral parmak izleri karşılaştırılarak bu metodun tanımlamada kullanılabilirliği araştırılmıştır. Tryptic soy broth içerisinde üretilen bakteri kültürleri formaldehit kullanılarak inaktive edildiler ve analize uygun hale getirmek için kurutuldular. DDC kamera ve Leica mikroskop cihazlarına sahip olan Renishaw marka Raman spektrometresi bu çalışmada kullanılmıştır. Elde edilen spektrumların görsel olarak yapılan incelemelerinde farklılıklar bulunmuştur. Örneğin, 856 ve 877 cm-1 bölgelerinde ortaya çıkan bantların yoğunluğu Gram negatif mikroorganizmalar ile kıyaslandığında S. aureus'dan elde edilen spektrumlarda daha fazla bulunmuştur. Buna ilaveten, 917 cm-1 bölgesinde elde edilen bant sadece S. Typhimurium'da bulunmuştur. Raman spektroskopisinin gıda kaynaklı patojenlerin genus seviyesinde tanımlanmasında güçlü bir araç olduğu söylenebilir, fakat metodun tür düzeyinde tanımlama yapabilmesi için standardizasyon çalışmalarına ihtiyaç duyulmaktadır.Due to its fastness, low-cost, and non-destructive features, the Raman spectroscopy has been found as a useful method to detect and identify microorganisms. In the present paper, the Raman spectral fingerprints of three major foodborne pathogens, including Escherichia coli, Salmonella typhimurium and Staphylococcus aureus were compared for the possible usefulness of this method for identification. Bacterial cultures grown into tryptic soy broth were inactivated with formaldehyde solution, and then freeze dried for analysis. A Renishaw Raman spectrometer system equipped with DDC camera and a Leica microscope was used in this study. Visual examination of the spectra showed significant differences. For example, intensity of bands around 856 and 877 cm-1 was much stronger in the spectra of S. aureus when compared to Gram negative organisms. In addition, the band at 917 cm-1 was only present in the spectra of S. typhimurium. It can be said that the Raman spectroscopy provides a powerful tool for the identification of foodborne pathogens at genus level, yet more research needs to be done to standardize the method for correct identification at species level

Investigation of the effectiveness of some plant compounds and essential oils of corymbia citriodora against foodborne pathogens

The purpose of this study was to determine the antibacterial activity of plant derived compounds and essential oils of Corymbia citriodoraagainst selected Gram negative and Gram positive foodborne pathogens in broth dilution assay. The combination of compounds (cineole, terpinen-4-ol and ?-terpineol; CT?T) were further tested at three different concentrations (0.2, 0.4 and 0.8%) for the killing effect against E. coliO157:H7 and L. monocytogenesin milk including whole fat and skim fat. CT?T showed antimicrobial activity against all bacteria tested at minimum inhibition concentrations (MICs) from 0.125% to 1% in broth dilution assay. Linalool was also found to be antimicrobial at MICs between 0.25% and 2%, but not for Enterococcus casseliflavus. Further study carried out in milk showed that CT?T at concentrations of 0.4% and 0.8% significantly reduced the population of E. coliO157:H7 under detection limit in skim milk, whereas it was only effective at 0.8% in whole fat milk. CT?T, on the other hand, shown to be less active towardsL. monocytogenesas only significant effect was observed at 0.8% in skim milk. Taken together results of the present study indicate that plant derived compounds could be valuable alternatives to inactivatefoodborne pathogens in milk.The purpose of this study was to determine the antibacterial activity of plant derived compounds and essential oils of Corymbia citriodoraagainst selected Gram negative and Gram positive foodborne pathogens in broth dilution assay. The combination of compounds (cineole, terpinen-4-ol and ?-terpineol; CT?T) were further tested at three different concentrations (0.2, 0.4 and 0.8%) for the killing effect against E. coliO157:H7 and L. monocytogenesin milk including whole fat and skim fat. CT?T showed antimicrobial activity against all bacteria tested at minimum inhibition concentrations (MICs) from 0.125% to 1% in broth dilution assay. Linalool was also found to be antimicrobial at MICs between 0.25% and 2%, but not for Enterococcus casseliflavus. Further study carried out in milk showed that CT?T at concentrations of 0.4% and 0.8% significantly reduced the population of E. coliO157:H7 under detection limit in skim milk, whereas it was only effective at 0.8% in whole fat milk. CT?T, on the other hand, shown to be less active towardsL. monocytogenesas only significant effect was observed at 0.8% in skim milk. Taken together results of the present study indicate that plant derived compounds could be valuable alternatives to inactivatefoodborne pathogens in milk

Effect of essential oil supplementation to diet on meat quality, fatty acid composition, performance parameters and intestinal microbiota of Japanese quails

The effect of essential oil (EO) supplementation on carcass characteristics ofJapanese quails and interactions between ingredients and intestinal morphologywere investigated in this study. A total of 250 quails were fed different diet: D1,basal diet (BD); D2, BD plus palmarosa oil (PO; 100 µg/kg diet); D3, BD plus lemonmyrtle oil (LMO; 100 µg/kg diet); D4, BD plus α-Tops (mixture of α-terpineol, cineoleand terpinene-4-ol; 100 µg/kg diet); and D5, BD plus cyclodextrin. Overall growthperformance was determined at multiple time points during 35 days of experiment.Carcass characteristics (fatty acid, pH and colour), intestinal morphology and the expression levels of meat quality-related genes including the insulin-like growth factor(IGF-1), myogenin and avian uncoupling protein (avUCP) were examined at the end ofthe trial. Additionally, intestinal microbiome of quails was studied by next-generationsequencing-based culture-independent analysis. Although the inclusion of EOs intothe diet had no effect on the growth performance of quails and the microbial profile,the significant changes in pH24 and colour (a*) of the quail's breast muscle (p < .05) inthe group receiving PO were observed. Additionally, oleic acid content in the breastmuscle was significantly higher in the EOs supplemented groups (p < .01). Quailsfed the PO supplemented diet had higher villus and relatively rich in oleic acid. Theexpression levels of IGF-1 and myogenin genes in quail's muscle were not affected,but the expression of avUCP gene was significantly lower in quails fed with LMO andα-Tops (p < .05). The results demonstrated variable effects of these treatments onintestinal morphology. Taken together, dietary inclusion of EOs is found to be beneficial and hence can be recommended for improving the quality of poultry meat