Modeling the effect of simultaneous use of allyl isothiocyanate and cinnamaldehyde on high hydrostatic pressure inactivation of Uropathogenic and Shiga toxin-producing Escherichia coli in ground chicken

Bioactive Compounds from Plant Origin as Natural Antimicrobial Agents for the Treatment of Wound Infections

The rising prevalence of drug-resistant bacteria underscores the need to search for innovative and nature-based solutions. One of the approaches may be the use of plants that constitute a rich source of miscellaneous compounds with a wide range of biological properties. This review explores the antimicrobial activity of seven bioactives and their possible molecular mechanisms of action. Special attention was focused on the antibacterial properties of berberine, catechin, chelerythrine, cinnamaldehyde, ellagic acid, proanthocyanidin, and sanguinarine against Staphylococcus aureus, Enterococcus spp., Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Serratia marcescens and Pseudomonas aeruginosa. The growing interest in novel therapeutic strategies based on new plant-derived formulations was confirmed by the growing number of articles. Natural products are one of the most promising and intensively examined agents to combat the consequences of the overuse and misuse of classical antibiotics.

High-pressure pulses for Aspergillus niger spore inactivation in a model pharmaceutical lipid emulsion

High hydrostatic pressure (HHP) is a non-thermal process widely used in the food industry to reduce microbial populations. However, rarely its effect has been assessed in products with high oil content. This study evaluated the efficacy of HHP (200, 250, and 300 MPa) at different temperatures (25, 35, and 45 °C) by cycles (1, 2, or 3) of 10 min in the inactivation of Aspergillus niger spores in a lipid emulsion. After treatments at 300 MPa for 1 cycle at 35 or 45 °C, no surviving spores were recovered. All treatments were modeled by the linear and Weibull models. The presence of shoulders and tails in the treatments at 300 MPa at 35 or 45 °C resulted in sigmoidal curves which cannot be described by the linear model, hence the Weibull + Tail, Shoulder + Log-lin + Tail, and double Weibull models were evaluated to elucidate the inactivation kinetics. The tailing formation could be related to the presence of resistance subpopulations. The double Weibull model showed better goodness of fit (RMSE <0.2) to describe the inactivation kinetics of the treatments with the higher spore reductions. HHP at 200-300 MPa and 25 °C did not reduce the Aspergillus niger spores. The combined HHP and mild temperatures (35-45 °C) favored fungal spore inactivation. Spore inactivation in lipid emulsions by HHP did not follow a linear inactivation. HHP at mild temperatures is an alternative to the thermal process in lipid emulsions.

Synergistic effect of high hydrostatic pressure, allyl isothiocyanate, and acetic acid on the inactivation and survival of pathogenic Escherichia coli in ground chicken

Meat and poultry are prone to contamination with foodborne pathogens sourced from the livestock or introduced from the processing environments. In this study, for retention of meat quality while assuring microbial food safety, mild levels of high hydrostatic pressure were hurdled with food-grade additives (i.e., allyl isothiocyanate [AITC] and acetic acid [AA], functioned as antimicrobials) to inactivate pathogenic Escherichia coli in ground chicken. The reductions of Shiga toxin-producing E. coli (STEC) O157:H7 and uropathogenic E. coli (UPEC) were described as a function of high hydrostatic pressure (200-350 MPa), process-holding time (10-25 min), AITC concentration (0.05-0.20% w/w), and AA concentration (0.10--0.30% w/w) using a full factorial design. The antimicrobials had little influence on bacterial inactivation without high pressure. Without the antimicrobials, a high-pressure treatment at 300 MPa and 4°C for 15 min reduced E. coli O157:H7 and UPEC by 1.52 and 2.52 log, respectively. A 5-log reduction was achieved when AITC and AA were combined with high pressure, indicating a synergistic effect. The survivors were further reduced to below the detection limit of 1 log CFU/g after subsequent storage tests at 4 and 10°C for 10 days. The STEC O157:H7 was found slightly more resistant than UPEC in our test matrix. The developed models showed good fits with experimental data (R²  > 0.95 for linear models; Pr > F (<0.0001) for dimensionless nonlinear models); which may help processors find/optimize the processing parameters to achieve target foodborne pathogens reduction for food safety requirement. PRACTICAL APPLICATION: Models were developed to predict the inactivation of pathogenic Escherichia coli in ground chicken by high-pressure processing (HPP) in combination with natural antimicrobial compounds. These models can be used to estimate/determine the HPP operation parameters and antimicrobial usage levels (i.e., allyl isothiocyanate and acetic acid) needed to achieve a specific microbial log reduction within the selected factor ranges. The operation parameters and clean-label ingredients are of interest in the food industry, which may benefit from the application of the models in achieving microbial safety, process optimization, and operation cost reduction.