Investigation of differences in susceptibility of Campylobacter jejuni strains to UV light-emitting diode (UV-LED) technology

Abstract Campylobacter jejuni remains a high priority in public health worldwide. Ultraviolet light emitting-diode technology (UV-LED) is currently being explored to reduce Campylobacter levels in foods. However, challenges such as differences in species and strain susceptibilities, effects of repeated UV-treatments on the bacterial genome and the potential to promote antimicrobial cross-protection or induce biofilm formation have arisen. We investigated the susceptibility of eight C. jejuni clinical and farm isolates to UV-LED exposure. UV light at 280 nm induced different inactivation kinetics among strains, of which three showed reductions greater than 1.62 log CFU/mL, while one strain was particularly resistant to UV light with a maximum reduction of 0.39 log CFU/mL. However, inactivation was reduced by 0.46–1.03 log CFU/mL in these three strains and increased to 1.20 log CFU/mL in the resistant isolate after two repeated-UV cycles. Genomic changes related to UV light exposure were analysed using WGS. C. jejuni strains with altered phenotypic responses following UV exposure were also found to have changes in biofilm formation and susceptibility to ethanol and surface cleaners

Production of medicated bedding straw: challenges and perspectives

American Society of Agricultural and Biological Engineers (ASABE) Annual International Meeting, Louisville, Kentucky, USA, 7-10 August, 2011Previous bacteriological findings have reported that animal disease outbreaks are associated with the quality of the animal environment. Animal bedding straw is a good source of bacteria and fungi, typically contaminated with (mycelia) yeasts and filamentous fungi species such as Aspergillus, Fusarium, Alternaria, Cladosporium, Epicoccum, Penicillium, Verticillium and Enterobacteria. The objective of this work was to assess the efficacy of different technologies on the production of medicated bedding straw. Four critical control points of an industrial straw disinfection processing line were identified. The levels of fungi and bacteria present in the straw during an industrially applied mechanical – chemical process were quantified. The plate counting revealed that propionic acid and formaldehyde chemicals reduced the microbial levels from the raw material and that they were more efficient on moulds than on bacteria. The potential use of ozone gas as an alternative greener technology to the current liquid chemical treatments was also evaluated. Trials conducted on ozone treatments (flow rates: 0.031, 0.125, 0.5 L/min, concentrations: 36, 99, 150 μg/mL, treatment time: 0, 5, 15, 30 mins, and residual times of 0 to 18 hrs) indicated that ozone successfully reduces the microbial counts and the fungi levels by more than 1.5 logs (cfu/g).Enterprise IrelandStraw Chip Ltd