Superheated steam sterilization of foodborne pathogens on pork belly: Biphasic kinetics, dual-action mechanisms, and logistic model validation.

Utilizing superheated steam to prepare traditional Chinese twice-cooked pork bellies, exploring its effects on the texture and flavor of fat layers

Dual purpose of superheated steam treatment: Inactivating surface pathogens of pork belly and replacing blanching

Superheated Steam Sterilization of Foodborne Pathogens on Pork Belly: Biphasic Kinetics, Dual-Action Mechanisms, and Logistic Model Validation

The emergence of antibiotic resistance in foodborne pathogens isolated from meat pro-ducts and their producing environment has been an increasing and leading threat to public health. The aim of the study was to identify pathogens and their antimicrobial resistance isolated from pig production to pork meat distribution phases. Through this study, food spoilage and foodborne or clinical pathogenic bacteria were isolated and identified from pork (belly and neck) meat product and its related environmental samples that include pig swabs, diets, feces, liquid manure, workers' gloves, dust fan swabs, carcass swabs, floor swabs, and drain water in the affiliated farm, slaughterhouse, meat processing plant, and in retail stores. All carcasses at the slaughterhouse and meat products at the meat processing plant were tracked from pigs at a targeted farm. Nine different selective media agars were used to effectively isolate various pathogenic bacteria. A total of 283 presumptive pathogenic bacteria isolated from 126 samples were selected and identified using MALDI-ToF MS. Twenty-three important foodborne pathogens were identified, and some of them, Shiga-toxin-producing E. coli (STEC), Listeria monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica, were further confirmed using PCR. The PFGE patterns of 12 STEC isolates were grouped by sample source or site. All the foodborne pathogens used in the study were not resistant to amoxicillin/clavulanate, ciprofloxacin, and gentamicin, whereas some of the STEC, L. monocytogenes, and S. aureus isolates were resistant to various antibiotics, including ampicillin, erythromycin, tetracycline, and vancomycin. The most common antimicrobial resistance pattern in the pathogenic STEC isolates was AMP-KAN-STR-SXT-TET. Consequently, this study provides valuable information for the distribution of antimicrobial-resistant pathogens along the pork meat production chain and can assist farmers and stakeholders to develop a systematic strategy for reducing the current emergence and spread of antimicrobial resistance in the different phases of pig production and distribution.

Superheated solar steam generation above 100 °C is critical for many important applications such as sterilization but is challenging to achieve under natural fluctuating low-flux solar illumination and often requires pressurization and the usage of expensive optical concentrators. Herein, we demonstrate generation of superheated steam under ambient pressure and low-flux solar illumination by integrating a recently emerged interfacial evaporation design into a solar vacuum tube. Within the tube, the water vapor, which is generated by a high-efficiency localized heating-based evaporator, is further heated by a heat exchanger into superheated steam without pressurization. The steam generator has shown tunable steam temperature from 102 to 165 °C and solar-to-steam conversion efficiency from 26 to 49% under 1 sun illumination. Owing to the minimized heat loss from the solar vacuum tube and the interfacial evaporation design, it enables stable generation of steam above 121 °C under ambient fluctuating solar illumination with an averaged solar flux of ∼600 W/m2. Effective sterilization is verified using both the Geobacillus stearothermophilus biological indicator and Escherichia coli bacteria, making portable solar steam sterilization and other steam-related applications feasible under ambient solar illumination.

Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on cherry tomatoes and oranges by superheated steam

A comparison of saturated steam and superheated steam for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes biofilms on polyvinyl chloride and stainless steel

Effectiveness of superheated steam for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, Salmonella Enteritidis phage type 30, and Listeria monocytogenes on almonds and pistachios

Inactivation of E. coli O157:H7, Salmonella enterica, and L. monocytogenes through semi-continuous superheated steam treatment with additional effects of enhancing initial germination rate and salinity tolerance

Objective The aim of the present study was to quantify hospital steam steriliser resource consumption to provide baseline environmental data and identify possible efficiency gains. We sought to find the amount of steriliser electricity and water used for active cycles and for idling (standby), and the relationship between the electricity and water consumption and the mass and type of items sterilised. Methods We logged a hospital steam steriliser's electricity and water meters every 5min for up to 1 year. We obtained details of all active cycles (standard 134°C and accessory or 'test' cycles), recording item masses and types. Relationships were investigated for both the weight and type of items sterilised with electricity and water consumption. Results Over 304 days there were 2173 active cycles, including 1343 standard 134°C cycles that had an average load mass of 21.2kg, with 32% of cycles <15kg. Electricity used for active cycles was 32652kWh (60% of total), whereas the water used was 1243495L (79%). Standby used 21457kWh (40%) electricity and 329200L (21%) water. Total electricity and water consumption per mass sterilised was 1.9kWhkg-1 and 58Lkg-1, respectively. The linear regression model predicting electricity use was: kWh=15.7+ 0.14×mass (in kg; R2=0.58, P<0.01). Models for water and item type were poor. Electricity and water use fell from 3kWhkg-1 and 200Lkg-1, respectively, for 5-kg loads to 0.5kWhkg-1 and 20Lkg-1, respectively, for 40-kg loads. Conclusions Considerable electricity and water use occurred during standby, load mass was only moderately predictive of electricity consumption and light loads were common yet inefficient. The findings of the present study are a baseline for steam sterilisation's environmental footprint and identify areas to improve efficiencies. What is known about the topic? There is increasing interest in the environmental effects of healthcare. Life cycle assessment ('cradle to grave') provides a scientific method of analysing environmental effects. Although data of the effects of steam sterilisation are integral to the life cycles of reusable items and procedures using such items, there are few data available. Further, there is scant information regarding the efficiency of the long-term in-hospital use of sterilisers. What does this paper add? We quantified, for the first time, long-term electricity and water use of a hospital steam steriliser. We provide useful input data for future life cycle assessments of all reusable, steam-sterilised equipment. Further, we identified opportunities for improved steriliser efficiencies, including rotating off idle sterilisers and reducing the number of light steriliser loads. Finally, others could use our methods to examine steam sterilisers and many other energy-intensive items of hospital equipment. What are the implications for practitioners? We provide useful input data for all researchers examining the environmental footprint of reusable hospital equipment and procedures using such equipment. As a result of the present study, staff in the hospital sterile supply department have reduced steam steriliser electricity and water use considerably without impeding sterilisation throughput (and reduced time inefficiencies). Many other hospitals could benefit from similar methods to improve steam steriliser and other hospital equipment efficiencies.

The Economics of Enteric Infections: Human Foodborne Disease Costs

The thermal death curve of dried spores of Bacillus stearothermophilus in saturated steam was characterized by three phases: (i) a sharp initial rise in viable count; (ii) a low rate of death which gradually increased; and (iii) logarithmic death at maximal rate. The first phase was a reflection of inadequate heat activation of the spore population. The second and third phases represented the characteristic thermal death curve of the spores in saturated steam. A jacketed steam sterilizer, equipped with a system for initial evacuation of the chamber, was examined for superheat during normal operation. Measurements of spore inactivation and temperature revealed superheat in surface layers of fabrics being processed in steam at 121 C. The high temperature of the fabric surfaces was attributed to absorption of excess heat energy from superheated steam. The superheated steam was produced at the beginning of the normal sterilizing cycle by transfer of heat from the steam-heated jacket to saturated steam entering the vessel.

The thermal death curve of dried spores of Bacillus stearothermophilus in saturated steam was characterized by three phases: (i) a sharp initial rise in viable count; (ii) a low rate of death which gradually increased; and (iii) logarithmic death at maximal rate. The first phase was a reflection of inadequate heat activation of the spore population. The second and third phases represented the characteristic thermal death curve of the spores in saturated steam. A jacketed steam sterilizer, equipped with a system for initial evacuation of the chamber, was examined for superheat during normal operation. Measurements of spore inactivation and temperature revealed superheat in surface layers of fabrics being processed in steam at 121 C. The high temperature of the fabric surfaces was attributed to absorption of excess heat energy from superheated steam. The superheated steam was produced at the beginning of the normal sterilizing cycle by transfer of heat from the steam-heated jacket to saturated steam entering the vessel.

The complexity of tracing foodborne pathogens in the food chain has increased significantly due to the long and complicated chain, the involvement of numerous links, and the presence of various types of pathogens at different stages and environments. Traditional typing techniques are not sufficient to meet the requirements of tracing pathogens in the food chain. Whole-Genome Sequencing (WGS) has gradually become an important technological tool for characterizing and tracing pathogens in the food chain due to comprehensive information, speed, and superior discriminatory power. This paper provides an overview of the advantages of WGS and its application in foodborne pathogen traceability. This paper focused on foodborne pathogen contamination pathways during the processing of animal foods in commercial restaurant kitchens and the potential contamination of milk, milk powder, and other dairy products by pathogens during processing in the dairy industry chain and environments. Improper handling practices during meat processing (i.e., using cloths, washing hands without soap, and cleaning boards with knives) were a critical point of foodborne pathogen cross-contamination in commercial kitchen premises. However, in dairy products, contamination of pathogens in raw milk was the main cause of foodborne disease outbreaks. Therefore, preventing the contamination of pathogens in food should not only be focused on hygiene measures during processing and in environments but also on the quality and hygiene of raw materials to prevent the spread of foodborne pathogens throughout the entire production chain. Further, Whole-Metagenome Sequencing and DNA sequence markers are considered to be the future direction of WGS. The purpose of this work is to promote the wider application of WGS during the processing of meat and dairy products and provide theoretical support for the rapid investigation and accurate traceability of foodborne pathogen outbreaks in food.

Combination effect of saturated or superheated steam and lactic acid on the inactivation of Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes on cantaloupe surfaces