Wastewater renovation using constructed soil filter (CSF): A novel approach

Constructed soil filter (CSF) also known as Soil Biotechnology (SBT) is a process for water renovation which makes use of formulated media with culture of soil macro- and microorganisms. CSF combines sedimentation, infiltration and biodegradation processes to remove oxidizable organics and inorganics of wastewater in a single facility. Operating experience shows hydraulic loading in the range of 0.05–0.25 m³/m² h and organic loading up to 200–680 g/m² d. The results show increase in dissolved oxygen levels, COD removal (from 352 mg/l to 20 mg/l); BOD removal (from 211 mg/l to 7.0 mg/l); suspended solids removal (from 293 mg/l to 16 mg/l); turbidity reduction (from 145 NTU to 5.3 NTU); iron (from 5 mg/l to 0.3 mg/l); arsenic (from 500 μg/l to 10 μg/l); total coliform and fecal coliform removal (from 145 × 10⁵ to 55 CFU/100 mL and 150 × 10⁸ to 110 CFU/100 mL respectively), with desired pathogen levels as per WHO standards, i.e. ≤10³ CFU/100 mL. CSF reveals advantages such as low HRT (0.5–2.0 h), low energy requirement (0.04 kW h/m³), no pre-treatment, high dissolved oxygen levels in the effluent, no biosludge production, no mechanical aeration and no odor, fish compatible water quality and evergreen ambience.     

The prevalence of Listeria, Salmonella, Escherichia coli and E. coli O157:H7 on bison carcasses during processing

Bison meat is a relatively new, emerging meat species gaining increased popularity in the US and European meat markets, but little is known of its microflora or pathogens that may be present. This study was carried out to determine the incidence of the foodborne pathogens Listeria, Salmonella, Escherichia coli/E. coli O157:H7 on slaughtered bison and to evaluate the bison slaughter process. Bison carcass sampling was carried out at monthly intervals over a period of 1 year at a Bison processing facility in the Midwestern United States. A total of 355 Bison carcasses were sampled by surface swabbing the carcasses at five points on the production line: pre-dehiding, post-evisceration, post-USDA inspection, post-washing and 24 h chilled carcass. Overall, the prevalence of Listeria spp., Salmonella spp., E. coli and E. coli O157:H7 was 18.3%, 3.94%, 38.3% and 1.13%, respectively. The prevalence of Listeria spp. at each sampling point tested was 42.24%, 18.1%, 6.03%, 1.72% and 3.77% while the prevalence of E. coli at each sampling point was: 88.79%, 73.28%, 52.59%, 56.89% and 11.3%, respectively. The data obtained suggests that current antimicrobial intervention strategies used at the plant are relatively effective in reducing Listeria and E. coli contamination on bison carcasses to some extent, however further study is required to determine the influence of current slaughter practices on carcass contamination. The data reported in this study to the authors’ knowledge is some of the first information reporting on the bacteriological status of Bison, and provides some useful baseline information for future research.     

Development and evaluation of aptamer magnetic capture assay in conjunction with real-time PCR for detection of Campylobacter jejuni

A prototype method for the concentration and detection of Campylobacter jejuni was developed using a previously reported biotinylated DNA aptamer in conjunction with qPCR. The so-called aptamer-based magnetic capture-qPCR (AMC-qPCR) assay was compared to a similar immunomagnetic separation (IMS)-qPCR assay. In small volume experiments (300 μl) applied to serially diluted C. jejuni suspended in buffer containing a mixed culture of other common food borne pathogens, the lower detection limit of the AMC-qPCR method was 1.1 log₁₀/300 μl C. jejuni cells, one log₁₀ better (lower) than that of IMS-qPCR (2.1 log₁₀ CFU/300 μl). AMC-qPCR capture efficiency was 10–13% at assay detection limit. In 10 ml scale-up experiments, the lower detection limit of AMC-qPCR was 2.0 log₁₀ CFU/10 ml with corresponding capture efficiency of 4–7%. Nucleic acid aptamers are promising alternatives to antibodies for magnetic bead-based capture followed by qPCR detection.     

产肠毒素性大肠埃希氏菌的检验

为查明夏季一起员工食物中毒的病原菌,采用GB/T4789-2003规定的PCR检测试剂盒进行检测。结果表明:从5份食物中毒者的便样和2份呕吐物中检出产肠毒素(LT)大肠埃希氏菌,其它肠道致病菌未检出。可以认为这起食物中毒是由产肠毒素(LT)大肠埃希氏菌所致。