Effect of the aqueous matrix on the inactivation of E. coli by permaleic acid

Deployment of a Novel Organic Acid Compound Disinfectant against Common Foodborne Pathogens

BACKGROUND

The disinfection process represents an important activity closely linked to the removal of micro-organisms in common processing systems. Traditional disinfectants are often not sufficient to avoid the spread of food pathogens; therefore, innovative strategies for decontamination are crucial to countering microbial transmission. This study aims to assess the antimicrobial efficiency of tetrapotassium iminodisuccinic acid salt (IDSK) against the most common pathogens present on surfaces, especially in food-borne environments.

METHODS

IDSK was synthesized from maleic anhydride and characterized through nuclear magnetic resonance (NMR) spectroscopy (both ¹H-NMR and ¹³C-NMR), thermogravimetric analysis (TGA) and Fourier Transform Infrared (FTIR) spectroscopy. The antibacterial activity was performed via the broth microdilution method and time-killing assays against Escherichia coli, Staphylococcus aureus, Salmonella enterica, Enterococcus faecalis and Pseudomonas aeruginosa (IDSK concentration range: 0.5-0.002 M). The biofilm biomass eradicating activity was assessed via a crystal violet (CV) assay.

RESULTS

The minimum inhibitory concentration (MIC) of IDSK was 0.25 M for all tested strains, exerting bacteriostatic action. IDSK also reduced biofilm biomass in a dose-dependent manner, reaching rates of about 50% eradication at a dose of 0.25 M. The advantages of using this innovative compound are not limited to disinfecting efficiency but also include its high biodegradability and its sustainable synthesis.

CONCLUSIONS

IDSK could represent an innovative and advantageous disinfectant for food processing and workers' activities, leading to a better quality of food and safer working conditions for the operators.

Biocides as Biomedicines against Foodborne Pathogenic Bacteria

Biocides are currently considered the first line of defense against foodborne pathogens in hospitals or food processing facilities due to the versatility and efficiency of their chemical active ingredients. Understanding the biological mechanisms responsible for their increased efficiency, especially when used against foodborne pathogens on contaminated surfaces and materials, represents an essential first step in the implementation of efficient strategies for disinfection as choosing an unsuitable product can lead to antibiocide resistance or antibiotic–biocide cross-resistance. This review describes these biological mechanisms for the most common foodborne pathogens and focuses mainly on the antipathogen effect, highlighting the latest developments based on in vitro and in vivo studies. We focus on biocides with inhibitory effects against foodborne bacteria (e.g., Escherichia spp., Klebsiella spp., Staphylococcus spp., Listeria spp., Campylobacter spp.), aiming to understand their biological mechanisms of action by looking at the most recent scientific evidence in the field.

Comparative analysis of peracetic acid (PAA) and permaleic acid (PMA) in disinfection processes

The growing demand to reduce chlorine usage and control disinfection byproducts increased the development of new strategies in wastewater treatments. Organic peracids are increasingly attracting interest in disinfection activities as a promising alternative to chlorine and chlorine-based agents. In this study, we assessed the antimicrobial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of a new organic peracid, permaleic acid (PMA) compared with the reference peracetic acid (PAA). Disinfectant properties were evaluated by i) disk diffusion agar, ii) broth microdilution, iii) antibiofilm properties. PMA demonstrated a 10- and 5-fold decrease in the microbial inhibitory concentration (MIC) value against E. coli and S. aureus respectively, compared to PAA. Results showed greater efficacy of PMA regarding wastewater (WW) and treated wastewater (TWW) disinfection at low concentrations. Furthermore, the biofilm degradation ability was only observed following PMA treatment, for both strains. Bacterial regrowth from biofilm matrix after PAA and PMA disinfection, in the absence and presence of organic matter, was evaluated. PMA was more efficient than PAA to prevent the regrowth of planktonic cells of S. aureus and E. coli. After PAA and PMA treatment, in the presence of organic matter, the bacterial regrowth inhibition was maintained up to 10 and 5 g/L, respectively. Based on these results, PMA could be used as a valid alternative to the currently used disinfection methods.