Recently, there has been significant research interest in cogasification of coal and various types of biomass blends to improve biomass gasification by reducing the tar content in the product gas. In addition, ash present in biomass catalyzes the gasification of coal. However, due to the fibrous nature of biomass and the large difference in gasification temperature of coal and biomass, cogasification in existing systems presents technical challenges. This paper documents research studies conducted on the cogasification of various types of coal and biomass using different types of gasifiers under various sets of operating conditions. In addition, the influence of cogasification on upstream and downstream processing is presented.
Salmonella is one of the top causes for bacterial foodborne infections in the United States, emphasizing the importance of controlling this pathogen for protecting public health. Poultry and poultry products are commonly associated with Salmonella, and interventions during production and processing are necessary to manage the risk of infection due to consumption of poultry products. In recent times, the demand for organic and antibiotic-free poultry has increased owing to consumer perceptions and concerns of increasing prevalence of antimicrobial-resistant (AMR) pathogens. However, the microbiological effect of these management practices is not clear. This study was conducted to determine the difference in the AMR of Salmonella isolated from poultry processed conventionally and organically. Fecal samples, carcass rinses, and environmental samples were collected over 1 year and analyzed for the prevalence of Salmonella and AMR. Results of this experiment showed that organic chickens were associated with statistically higher levels of Salmonella during early processing steps. However, no difference in Salmonella prevalence was observed between organic and conventional carcasses postchill. In addition, for most antimicrobial agents tested, prevalence of AMR Salmonella in conventional processing was lower in this study than was reported by the National Antimicrobial Resistance Monitoring System for chickens at slaughter. These observations indicate that organic methods may introduce greater risk of Salmonella contamination; however, proper interventions during processing can abate this risk. In addition, this study supports the assertion that raising chickens without the use of antibiotics may result in lower prevalence of AMR Salmonella.
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Husbandry practices for laying hens in commercial egg production is a topic of interest from a social, economic, and regulatory standpoint. Animal welfare concerns regarding the use of conventional cages have arisen and consumer perceptions of hen welfare have led to a higher demand for cage-free eggs. The aim of this study was to assess the impact of housing systems on prevalence, persistence, and antimicrobial resistance (AMR) of Campylobacter from laying hens and shell eggs. A total of 425 samples were collected over a 10-month period from the North Carolina Layer Performance and Management Test and Campylobacter isolates were identified by serological, biochemical, and molecular tests. Genetic variability was evaluated using pulsed-field gel electrophoresis (PFGE) and AMR testing was performed. Prevalence of Campylobacter spp. ranged from 11.1% in the enrichable cages to 19.7% in the conventional systems. A greater prevalence of Campylobacter was found in the fecal swab samples from free-range birds compared with those of birds housed in the more intensive housing systems (p > 0.05). Overall, 72 isolates were confirmed as Campylobacter spp. by PCR. More than 90% of the isolates (n = 66) were identified as Campylobacter jejuni, followed by Campylobacter coli (n = 6). C. jejuni isolates displayed high levels of resistance to tetracycline (67%). Genetic variability of Campylobacter was high, with more than 20 PFGE patterns identified. Pattern "a" comprised 42% of isolates from all housing systems and was also the most persistent. This study suggests that housing systems of laying hens used for commercial shell egg production may impact the rate of Campylobacter shedding by layers. Isolation rates and tetracycline resistance levels of this pathogen are still of concern, emphasizing the need for well-implemented biosecurity measures on the farm.
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