Response surface modeling for the inactivation ofBacillus cereuson cooked spinach by natural antimicrobials at various temperatures

The Inclusion of the Food Microstructural Influence in Predictive Microbiology: State-of-the-Art

Predictive microbiology has steadily evolved into one of the most important tools to assess and control the microbiological safety of food products. Predictive models were traditionally developed based on experiments in liquid laboratory media, meaning that food microstructural effects were not represented in these models. Since food microstructure is known to exert a significant effect on microbial growth and inactivation dynamics, the applicability of predictive models is limited if food microstructure is not taken into account. Over the last 10-20 years, researchers, therefore, developed a variety of models that do include certain food microstructural influences. This review provides an overview of the most notable microstructure-including models which were developed over the years, both for microbial growth and inactivation.

Synergistic effects of blue light-emitting diodes in combination with antimicrobials against Escherichia coli O157:H7 and their mode of action

This study was conducted to evaluate the antibacterial effect of 460-470 nm light-emitting diodes illumination (460/470 LED) combined with various antimicrobials at inactivating Escherichia coli O157:H7 and identify the antibacterial mechanisms. When carvacrol, thymol, citric acid, malic acid, citrus fruit extract, 3% NaCl, or 5% NaCl was combined with 460/470 LED, there was a higher reduction in E. coli O157:H7 compared to 460/470 LED treatment or antimicrobials alone at 4 °C. Particularly, a marked synergistic effect (>8.74 log₁₀ CFU/ml) was observed when 460/470 LED was combined with carvacrol, malic acid, citrus fruit extract, or 3% NaCl. Levels of intracellular ROS and lipid peroxidation of E. coli O157:H7 were higher in the combination of 460/470 LED and antimicrobials compared to individual treatments. Moreover, the combination treatment increased depolarization of the cell membrane leading to membrane damage as well as the loss of DNA integrity. Thus, adding antimicrobial treatment to 460/470 LED could improve its efficacy against pathogenic bacteria such as E. coli O157:H7.