Corrosion and performance of dust palliatives : laboratory and field studies

This report details laboratory and field experiments on BioPreferred® dust suppressants to assess performance and corrosion characteristics. Numerous bio-based dust suppressant products are marketed, but little data are available to assess performance for dust abatement and corrosion of common metals. A laboratory study used an air impingement device and the Portable In-Situ Wind ERosion Laboratory (PI-SWERL) to simulate wind speeds similar to those in field conditions for rotary wing aircraft. Laboratory corrosion studies used metal coupons imbedded in soil treated with dust palliative. Field trials were conducted using ground vehicle traffic to minimize cost and lower safety concerns while increasing surface wear from repetitive traffic. These studies clearly show that bio-based products demonstrate low corrosion potential with similar dust abatement performance to synthetic-based agents.

Vacuum and Infrared-Assisted Hot Air Impingement Drying for Improving the Processing Performance and Quality of Poria cocos (Schw.) Wolf Cubes

The objective of this study was to develop an efficient drying technology for poria cubes in order to improve product quality. Poria cubes were dried using different methods, including air impingement drying, infrared-assisted air impingement drying, vacuum drying, two-stage vacuum drying, and infrared-assisted air impingement drying. The results were compared with those from hot air drying. For the two-stage drying, the tested conditions were the first stage of vacuum drying with temperatures between 65–85 °C and a switching moisture ratio of 70–90%. The second stage infrared-assisted air impingement drying also had temperatures 65–85 °C. The drying kinetics (effective moisture diffusivity (Deff), Biot number (Bi), and mass transfer coefficient (k) were studied via the product qualities (broken ratio, firmness, microstructure, and water-soluble polysaccharide content) and specific energy consumption (SEC) of the drying processes. The results showed that two-stage drying led to the lowest drying time and energy consumption, and also obtained the best qualities. Box–Behnken experimental design with response surface methodology (RSM) was used to optimize the two-stage operating conditions as 82 °C under vacuum drying until a moisture content of 81% and a temperature of 69 °C with infrared-assisted air impingement drying was achieved. These findings suggested that two-stage vacuum and infrared-assisted air impingement drying is a promising method for producing high quality and energy efficient dried poria cubes.

Process Humidity Affects Salmonella Lethality at the Surface and Core of Impingement-Cooked Meat and Poultry Products

Recent revisions to USDA FSIS compliance and safe harbor guidelines for ready-to-eat meat and poultry products addressed process humidity requirements. Given the lack of prior data for impingement-cooked products, this project aimed to evaluate the impact of process humidity on Salmonella lethality at the product core and surface, and compliance of the results with USDA FSIS lethality performance standards. Whole muscle beef strips, ground beef patties, whole muscle chicken breast fillets, and breaded ground chicken patties were inoculated with an 8-serovar cocktail of Salmonella. Beef and chicken samples were cooked in a pilot-scale moist-air impingement oven to a core temperature of 70.0 or 72.8°C, respectively, immediately quenched in liquid nitrogen, and dissected to obtain core and surface samples. Variables included oven temperature (218, 232°C), air velocity (0.7 and 2.8 m/s), and oven humidity (0.7, 15, 30, or 70% moisture by volume (% v/v)). Additional treatments were performed to examine the impact of supplemental critical control processes, such as increased endpoint temperature, post-oven carryover time, and pre- or post-oven steam treatments. Salmonella reductions of >7 log were reliably achieved in chicken patties regardless of the processing variables; however, none of the treatments reliably ensured >6.5 log reductions of Salmonella in ground beef. A majority of whole-muscle samples failed to meet the required performance lethality when processed at 0.7% v/v; however, Salmonella inactivation was significantly improved (P < 0.05) at oven humidities of > 30% v/v. Dry oven conditions achieved greater Salmonella lethality at the core than at the surface for multiple products (P < 0.05). The efficacies of minimal and supplemental critical controls were product-, process-, and humidity-dependent (P < 0.05). Overall, process humidity and product variability should be considered in regulatory requirements and process validations.