Non thermal plasma as an alternative tool for milk processing

In this study, a novel cold plasma system has been tested and optimized as an alternative processing method for decontamination of E. coli. Salmonella Typhirimium and Staphylococcus aureus in milk samples. Further to assessing the system for optimal decontamination parameters, changes to the chemical composition and sensory qualities of milk were also tested by well established methods such as GC\u2013MS, SDS-PAGE and colorimetric testing. The inactivation of test microorganisms reached the highest level after 3 minutes of application which was followed by a slower rate of inactivation. Plasma application did not significantly affect the pH, colour, proteins, fatty acid composition, and volatile compounds of milk samples. The findings of this work have preliminarily established the feasibility of using plasma technology for milk decontamination while retaining the nutritional and sensory quality. If established this technology will provide both health and economical impacts

Biochemical changes to milk following treatment by a novel, cold atmospheric plasma system

It has previously been shown that non-thermal (i.e., cold) plasma can successfully decontaminate milk from Escherichia coli. This study investigated the possible biochemical changes to the protein, free fatty acids and volatiles profiles of whole raw milk samples following application of cold plasma. Raw milk was treated with a cold plasma system at intervals of 0, 3, 6, 9, 12, 15 and 20min. Significant changes were observed for 1 octanol (P<0.05), 2 heptanone (P<0.01), 2 hexenal (P<0.01), 2 octenal (P<0.05), nonanal and benzaldehyde (P<0.001). Plasma treatment did not result in significant changes to the lipid composition of raw milk. However, exposure to cold plasma significantly increased the total aldehyde content following 20min treatment. No significant difference was observed in the total ketone or alcohol levels

Phospholipid analogues of Porphyromonas gingivalis

Porphyromonas has lipids containing hydroxy acids and C(16:0) and iso- C(15:0) major monocarboxylic acids among others. Nothing is known of its individual phospholipid molecular species. The aim of this study was to determine molecular weights and putative identities of individual phospholipid molecular species extracted from Porphyromonas gingivalis (seven strains), P. asaccharolytica (one strain) and P. endodontalis (two strains). Cultures on Blood-Fastidious Anaerobe Agar were harvested, washed and freeze- dried. Phospholipids were-extracted and separated by fast atom bombardment mass spectrometry (FAB MS) in negative-ion mode. Phospholipid classes were also separated by thin layer chromatography (TLC). The major anions in the range m/z 209-299 were consistent with the presence of the C(13:0), C(15:0), C(16:0) and C(18:3) mono-carboxylate anions. Major polar lipid anion peaks in the range m/z 618-961 were consistent with the presence of molecular species of phosphatidylethanolamine, phosphatidylglycerol and with unidentified lipid analogues. Porphyromonas gingivalis differed from comparison strains of other -species by having major anions with m/z 932, 946 and 960. Unusually, a feline strain of P. gingivalis had a major peak of m/z 736. Selected anions were studied by tandem FAB MS which revealed that-peaks with m/z 653 and 946 did not correspond to commonly occurring classes of polar lipids. They were however, glycerophosphates. It is concluded that the polar lipid analogue profiles obtained with Porphyromonas are quite different from those of the genera Prevotella and Bacteroides but reveal heterogeneity within P. gingivalis

The effect of low temperature plasma on volatile profile of milk

In this study, the time dependent effect of non thermal plasma (NTP) application (15 kV, AC power supply) on the volatile profile of milk was investigated by gas chromatography\u2013mass spectrometry, based on solid-phase microextraction (SPME) analysis. Plasma was applied at time intervals of 0, 3, 6, 9, 12, 15 and 20 min. More than 50 volatile organic compounds were separated and identified. The exposure to NTP treatments resulted in a significant increase in the content of the total aldehydes for milk samples treated for 15 min. Furthermore, the comparison of chromatographic data of control samples with those treated with NTP suggested that the content of total alcohols in the NTP treated samples was slightly higher, while that of the hydrocarbons was not affected by LTP treatment. The molecules significantly affected by NTP treatments included; 2 heptanone, nonanal, 2 octenal, 1 octanol and benzaldyde which showed a marked increase following exposure to the plasma