J. Wunderlich

Sterilization efficiency of a cascaded dielectric barrier discharge.

Aims:  To investigate the microbial inactivation efficiency of a newly developed cascaded dielectric barrier discharge (CDBD) set‐up against various micro‐organisms on polyethylene terephthalate (PET) foils.

Antimicrobial efficiency of titanium dioxide-coated surfaces

Aims:  Development and evaluation of an antimicrobially active titanium dioxide coating.

Influence of relative gas humidity on the inactivation efficiency of a low temperature gas plasma

Aims:  To investigate the effect of relative gas humidity on the inactivation efficiency of a cascaded dielectric barrier discharge (CDBD) in air against Aspergillus niger and Bacillus subtilis spores on PET foils.

Modification of bacterial structures by a low‐temperature gas plasma and influence on packaging material

Aims:  To investigate the effect of a cascaded dielectric barrier discharge (CDBD) treatment on the biological structure of a selected bacterium and on the properties of different polymer films.

Antimicrobial activity of hop extracts against foodborne pathogens for meat applications

The objective of this study was the fundamental investigation of the antimicrobial efficiency of various hop extracts against selected foodborne pathogens in vitro, as well as their activity against Listeria monocytogenes in a model meat marinade and on marinated pork tenderloins.

Recent findings in pulsed light disinfection

Nonthermal disinfection technologies are gaining increasing interest in the field of minimally processed food in order to improve the microbial safety or to extend the shelf life. Especially fresh‐cut produce or meat and fish products are vulnerable to microbial spoilage, but, due to their sensitivity, they require gentle preservation measures. The application of intense light pulses of a broad spectral range comprising ultraviolet, visible and near infrared irradiation is currently investigated as a potentially suitable technology to reduce microbial loads on different food surfaces or in beverages. Considerable research has been performed within the last two decades, in which the impact of various process parameters or microbial responses as well as the suitability of pulsed light (PL) for food applications has been examined. This review summarizes the outcome of the latest studies dealing with the treatment of various foods including the impact of PL on food properties as well as recent findings about the microbicidal action and relevant process parameters.

Pulsed light induced damages in Listeria innocua and Escherichia coli

Pulsed light (PL) is an upcoming nonthermal decontamination technology mainly used for surface sterilization. The objective of this study was to investigate the extent of cellular damage caused by PL treatments of Listeria innocua and Escherichia coli on a polysaccharide surface in order to gain knowledge about the main inactivation pathways.

Impact of pulsed light on cellular activity of Salmonella enterica

The objective of this study was a comprehensive characterization of physiological changes of Salmonella enterica induced by intense broad spectrum pulsed light (PL). After exposing the bacteria to this nonthermal decontamination technology on a gel surface, multiple viability parameters beyond culturability were assessed.

ATP-synthesis capacity of pulsed light-exposed bacteria

The ability of four different bacteria to synthesize new ATP upon exposure to different doses of pulsed-light (PL) irradiation was investigated. The bacterial cells were PL treated on a gel surface, resuspended in phosphate buffered saline (PBS) and subsequently incubated in Tryptic Soy Broth (TSB) at 37°C. Cellular ATP levels were monitored during a 2h incubation period and compared to the respective colony count data. Although PL affected ATP production in a dose dependent manner, the results showed that bacteria, which had rendered unculturable after PL exposure, are still capable of generating significant quantities of ATP. Escherichia coli and Listeria innocua proved to be more resistant to PL than Salmonella enterica and Staphylococcus aureus, which was supported by the colony count data and the ATP synthesis capacity. These findings underline that bacteria undetectable by culture-based methods may still show cellular activity and synthesize new ATP.