Variability in resistance to Cold Atmospheric Plasma (CAP) and Ultraviolet light (UV) and multiple stress resistance analysis of pathogenic verocytotoxigenic Escherichia coli (VTEC)

New Trends in Photodynamic Inactivation (PDI) Combating Biofilms in the Food Industry-A Review

Biofilms cause problems in the food industry due to their persistence and incompetent hygiene processing technologies. Interest in photodynamic inactivation (PDI) for combating biofilms has increased in recent years. This technique can induce microbial cell death, reduce cell attachment, ruin biofilm biomolecules and eradicate structured biofilms without inducing microbial resistance. This review addresses microbial challenges posed by biofilms in food environments and highlights the advantages of PDI in preventing and eradicating microbial biofilm communities. Current findings of the antibiofilm efficiencies of this technique are summarized. Additionally, emphasis is given to its potential mechanisms and factors capable of influencing biofilm communities, as well as promising hurdle strategies.

Photocatalytic TiO2-Based Nanostructured Materials for Microbial Inactivation

Pathogenic microorganisms can spread throughout the world population, as the current COVID-19 pandemic has dramatically demonstrated. In this scenario, a protection against pathogens and other microorganisms can come from the use of photoactive materials as antimicrobial agents able to hinder, or at least limit, their spreading by means of photocatalytically assisted processes activated by light—possibly sunlight—promoting the formation of reactive oxygen species (ROS) that can kill microorganisms in different matrices such as water or different surfaces without affecting human health. In this review, we focus the attention on TiO2 nanoparticle-based antimicrobial materials, intending to provide an overview of the most promising synthetic techniques, toward possible large-scale production, critically review the capability of such materials to promote pathogen (i.e., bacteria, virus, and fungi) inactivation, and, finally, take a look at selected technological applications.

Use of Cold Plasma To Inactivate Escherichia coli and Physicochemical Evaluation in Pumpkin Puree

This work aimed to study the pumpkin puree processing by cold plasma corona discharge as an alternative to heat treatment to reduce Escherichia coli contamination and evaluate physicochemical alterations, using argon (Ar) as the process gas. The treatment time to verify E. coli inactivation was between 2 and 20 min, while physicochemical alterations were analyzed at 5, 10, 15, and 20 min. Cold plasma corona discharge technology to inactivate E. coli proved to be promising, reaching 3.62 log cycles of reduction at 20 min of treatment. The inactivation kinectics showed a tendency of higher decrease with time. Physicochemical characteristics indicate that plasma induces a decrease of pH; however, there is an indication that process gases have an important role and react with the environment and procedure reactive species. This technology may reduce the total carotenoid content of pumpkin puree and in color, mainly the a* parameter, which showed great reduction.

Microbiological interactions with cold plasma

There is a diverse range of microbiological challenges facing the food, healthcare and clinical sectors. The increasing and pervasive resistance to broad-spectrum antibiotics and health-related concerns with many biocidal agents drives research for novel and complementary antimicrobial approaches. Biofilms display increased mechanical and antimicrobial stability and are the subject of extensive research. Cold plasmas (CP) have rapidly evolved as a technology for microbial decontamination, wound healing and cancer treatment, owing to the chemical and bio-active radicals generated known collectively as reactive oxygen and nitrogen species. This review outlines the basics of CP technology and discusses the interactions with a range of microbiological targets. Advances in mechanistic insights are presented and applications to food and clinical issues are discussed. The possibility of tailoring CP to control specific microbiological challenges is apparent. This review focuses on microbiological issues in relation to food- and healthcare-associated human infections, the role of CP in their elimination and the current status of plasma mechanisms of action.