Maturation of pathogenic biofilms induces enhanced resistance against gaseous chlorine dioxide

Biofilms are surface-associated microbial clusters embedded in extracellular polymeric substances. Biofilms formed on food-contact surfaces create challenges for the food industry due to their increased tolerance to antimicrobial agents and disinfectants. This study aimed to evaluate the effect of the biofilm maturation period on their resistance to gaseous ClO2. Listeria monocytogenes, Salmonellaserotype Typhimurium, and Escherichia coli O157:H7 biofilms formed on stainless steel (SS) and high-density polyethylene (HDPE) surfaces were investigated. The total cell mass and protein content significantly increased (P < .05) between the second and the fifth day of maturation, and the biofilms' resistance to gaseous ClO2 increased as they matured. Generally, the cell counts of 0-day-old L. monocytogenes, Salm. Typhimurium, and E. coli O157:H7 biofilms on SS and HDPE reduced below the detection limit (0.48 log CFU/cm2) within 5 min. The cell counts of 2-day-old biofilms of the three pathogens were reduced by 6.22 to over 7.52 log, while those of 5-day-old biofilms were reduced by 3.64 to over 6.34 log after 20 min of treatment with 30 ppmv of gaseous ClO2. Therefore, as resistance increases with biofilm maturation, daily gaseous ClO2 treatment would maximize the antimicrobial efficacy of the cleaning strategy against biofilms.

Anthocyanins Recovered from Agri-Food By-Products Using Innovative Processes: Trends, Challenges, and Perspectives for Their Application in Food Systems

Anthocyanins are naturally occurring phytochemicals that have attracted growing interest from consumers and the food industry due to their multiple biological properties and technological applications. Nevertheless, conventional extraction techniques based on thermal technologies can compromise both the recovery and stability of anthocyanins, reducing their global yield and/or limiting their application in food systems. The current review provides an overview of the main innovative processes (e.g., pulsed electric field, microwave, and ultrasound) used to recover anthocyanins from agri-food waste/by-products and the mechanisms involved in anthocyanin extraction and their impacts on the stability of these compounds. Moreover, trends and perspectives of anthocyanins' applications in food systems, such as antioxidants, natural colorants, preservatives, and active and smart packaging components, are addressed. Challenges behind anthocyanin implementation in food systems are displayed and potential solutions to overcome these drawbacks are proposed.

Decontamination of SARS-CoV-2 contaminated N95 filtering facepiece respirators using artificial sun lamps

Aims

Assess the feasibility of using light from artificial sun lamps to decontaminate N95 filtering facepiece respirators (FFRs) contaminated with SARS‐CoV‐2.

Methods and Results

FFR coupons or whole FFRs contaminated with 5 log₁₀ TCID₅₀ (target concentration) SARS‐CoV‐2 in culture media, simulated saliva, or simulated lung fluid were dried for 1–2 h, then exposed to light from tanning and horticulture lamps to assess decontamination. Exposed coupons and whole FFRs showed SARS‐CoV‐2 inactivation for all matrices tested. Furthermore, FFRs still met performance specifications after five decontamination cycles.

Conclusions

It is feasible that artificial sunlight from these sun lamps can be used to decontaminate FFRs provided the UV dose is sufficient and the light is unobstructed. Furthermore, decontamination can be performed up to five times without degrading FFR performance.

Significance and Impact of the Study

This research shows a proof of principle that artificial sun lamps may be an option to decontaminate SARS‐CoV‐2 on N95 FFRs. UV doses required for inactivation to levels below detection ranged from 4 to 37·8 J cm⁻² depending on the light source, virus matrix and FFR type.