Combined treatment of ß-resorcylic acid and capric acid enhances mild heat pasteurization for inactivating Salmonella Typhimurium in orange juice.

This study aimed to develop a pasteurization method against Salmonella enterica serovar Typhimurium in orange juice using low concentrations of naturally derived antimicrobials, ß-resorcylic acid and capric acid, under mild temperature conditions based on their synergistic bactericidal interactions. Response surface methodology was used to construct a model based on four variables, namely ß-resorcylic acid (1, 3, 5, 7, and 9 mM), capric acid (0.05, 0.10, 0.15, 0.20, and 0.25 mM), treatment temperature (35, 40, 45, 50, and 55 °C), and time (1, 2, 3, 4, and 5 min), and the resulting model was used to predict the reduction in the content of fastidious bacteria (S. Typhimurium) in orange juice and to identify the optimal treatment combination for juice pasteurization. A second-order quadratic model for Salmonella reduction showed a high regression coefficient (R2 = 0.9503), and the accuracy of the predictive model was also verified (R2 = 0.9317). The optimal conditions determined by ridge analysis were 8.43 mM ß-resorcylic acid combined with 0.10 mM capric acid at 43.46 °C for 3.03 min, and these yielded an estimated 7.41-log reduction. Treatment times <30 s under the optimal conditions also resulted in a >5.7-log reduction. The combined treatment did not affect either the pH or sugar concentration in brix, and average pH and sugar concentration values of 3.86 and 11.05% were observed, respectively. The distinct advantage of the developed method is its ability to effectively reduce the content of S. Typhimurium over a short time under low temperature conditions through the addition of consumer-preferred naturally derived antimicrobials. The predictive model could be used to determine the most cost-efficient amounts of antimicrobial agents and conditions (treatment temperature and time) for sterilizing orange juice.

Sewage, Salt, Silica and SARS-CoV-2 (4S): An economical kit-free method for direct capture of SARS-CoV-2 RNA from wastewater.

Wastewater-based epidemiology is an emerging tool to monitor COVID-19 infection levels by measuring the concentration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater. There remains a need to improve wastewater RNA extraction methods' sensitivity, speed, and reduce reliance on often expensive commercial reagents to make wastewater-based epidemiology more accessible. We present a kit-free wastewater RNA extraction method, titled "Sewage, Salt, Silica and SARS-CoV-2" (4S), that employs the abundant and affordable reagents sodium chloride (NaCl), ethanol and silica RNA capture matrices to recover 6-fold more SARS-CoV-2 RNA from wastewater than an existing ultrafiltration-based method. The 4S method concurrently recovered pepper mild mottle virus (PMMoV) and human 18S ribosomal subunit rRNA, both suitable as fecal concentration controls. The SARS-CoV-2 RNA concentrations measured in three sewersheds corresponded to the relative prevalence of COVID-19 infection determined via clinical testing. Lastly, controlled experiments indicate that the 4S method prevented RNA degradation during storage of wastewater samples, was compatible with heat pasteurization, and could be performed in approximately 3 hours. Overall, the 4S method is promising for effective, economical, and accessible wastewater-based epidemiology for SARS-CoV-2, providing another tool to fight the global pandemic.

Heat-Pasteurization Process for Inactivation of Nonproteolytic Types of Clostridium botulinum in Picked Dungeness Crabmeat.

Development of a heat-pasteurization process is described for picked meat of Dungeness crabs ( Cancer magister ) contained in oxygen-impermeable flexible pouches, For each time-temperature treatment, 30 samples, each inoculated with an equal mixture of three strains of C. botulinum nonproteolytic type B, for a total of 107 spores, provided the basis for calculation of the thermal resistance (a 7D process). Following heat processing, the crabmeat was removed from the pouches and transferred to enrichment medium where it was incubated anaerobically for 150 days. Endpoints at which spores survived were determined by the presence of toxin in the enrichment medium. Process times ranged from 90 min at 88.9°C to 20.3 min at 94.4°C. D values (the time at each temperature required to reduce the inoculum by 1 log) ranged from 12.9 for the 88.9°C process to 2.9 for the 94.4°C process. The relative sterilization value, F0 was .054 and the pasteurization value, , was 240. This pasteurization process safely extends refrigerated shelf life by inactivating spores of Clostridium botulinum nonproteolytic types B, E, and F and also non-spore-forming pathogens such as Listeria monocytogenes . The process does not, however, inactivate the heat-resistant proteolytic strains of C. botulinum or other more heat-resistant spore-formers. The packages and master cartons of the pasteurized product, therefore, should be labeled "Keep refrigerated-Continuous refrigeration below 38°F (3.3°C) required."