Distribution of Campylobacter jejuni isolates from turkey farms and different stages at slaughter using pulsed-field gel electrophoresis and flaA-short variable region sequencing

The aim of this study was to assess the diversity of thermotolerant Campylobacter spp. isolated from turkey flocks at six rearing farms 1-2 weeks prior to slaughter (360 faecal swab samples) and from 11 different stages at the slaughterhouse (636 caecal, environmental, neck skin and meat samples). A total of 121 Campylobacter isolates were identified to species level using a multiplex PCR assay and were typed by pulsed-field gel electrophoresis (PFGE) and flaA-short variable region (SVR) sequencing. All Campylobacter isolates were identified as Campylobacter jejuni. PFGE analysis with KpnI restriction enzyme resulted in 11 PFGE types (I-XI) and flaA SVR typing yielded in nine flaA-SVR alleles. The Campylobacter-positive turkey flocks A, C and E were colonized by a limited number of Campylobacter clones at the farm and slaughter. The present study confirms the traceability of flock-specific strains (PFGE types I, V and IX; flaA types 21, 36 and 161) from the farm along the entire processing line to meat cuts. It seems that stress factors such as high temperature of the defeathering water (54-56 °C), drying of the carcass skin during air chilling (24 h at 2 °C), and oxygen in the air could not eliminate Campylobacter completely. Campylobacter-negative flocks became contaminated during processing by the same subtypes of Campylobacter introduced into the slaughter house by preceeding positive flocks even if they were slaughtered on subsequent days. Proper and efficient cleaning and disinfection of slaughter and processing premises are needed to avoid cross-contamination, especially in countries with a low prevalence of Campylobacter spp. The majority of flaA SVR alleles displayed a distinct association with a specific PFGE type. However, a linear relationship for all strains among both typing methods could not be established. To specify genetic relatedness of strains, a combination of different genotyping methods, is needed.     

内蒙古羊屠宰场致泻性大肠杆菌和沙门氏菌污染状况分析

为了解内蒙古地区羊屠宰场各屠宰环节致泻性大肠杆菌和沙门氏菌的携带情况,评估是否存在污染风险,选取不同规模屠宰场,用棉拭子法分别采集不同屠宰环节样品349份,36 h内进行试验;应用PCR方法分离鉴定病原菌,对鉴定为致泻性大肠杆菌的分离株进行16S r DNA测序并构建系统发育树。结果显示:从刚宰杀的羊胴体表面和环境中共分离到致泻性大肠杆菌12株,其中11株携带毒力基因elt,1株携带毒力基因eae和elt;大中型屠宰场(1.21%)的致泻性大肠杆菌阳性率低于小型屠宰场(5.43%),不同规模屠宰场的预冷间均未检出致泻性大肠杆菌和沙门氏菌;从屠宰环境中分离出1株携带inv A基因的沙门氏菌,阳性率为0.29%;经高压冲洗和排酸预冷等屠宰工艺后,在羊胴体表面均未发现致泻性大肠杆菌和沙门氏菌。     

上海市崇明区生猪屠宰行业及监管现状调查

为了解辖区内生猪屠宰行业现状,进一步完善生猪屠宰监督管理,上海市对现存的2家生猪定点屠宰企业及检疫队伍开展了调查研究。结果显示:本区生猪定点屠宰的猪源主要为崇明本地猪,屠宰检疫合格率达99.99%,斥品检出率低于0.5%的警戒线,产品主要销往上海市;屠宰检疫队伍由10名官方兽医和14名签约兽医组成,官方兽医具有年轻化、高学历等特征,签约兽医年龄阶层分布合理,具有从业经验丰富等特征;企业\"瘦肉精\"抽检率高于3%的最低标准,非洲猪瘟自检达到\"批批检、全覆盖\"的要求。调研中发现存在生猪产品供需不平衡,屠宰检疫队伍综合水平不高,屠宰企业自检费用高等问题,这提示应发展生猪产加销全产业链,开展检疫人员分类培训并改善待遇,积极争取政策资金支持,推动生猪屠宰监管的高质量发展。     

加强法制建设，落实生猪屠宰厂（场）主体责任的思考

屠宰厂(场)开展入场查物验证和肉品品质检验是落实主体责任的重要体现。目前相关法律法规对屠宰厂(场)未履行查物验证义务缺少处罚依据,对肉品品质检验的人员资质、人数和印章使用的规定不够详细,肉品品质检验合格证填写烦琐。为了更好地落实屠宰厂(场)主体责任,应增加对屠宰场不履行入场查物验证的处罚法律依据,明确肉品品质检验员专业、人数和健康证的要求,规范和简化肉品品质检验合格证的填写。     

AF+SBR工艺对屠宰废水处理效果的实验研究

本实验研究AF(厌氧生物滤池)+SBR(序批式活性污泥法)组合工艺对屠宰废水的处理效果,为屠宰废水处理提供一种科学经济有效的方法。AF+SBR组合工艺以3L/T的流量进水,总HRT为24h,厌氧12h,好氧12h,曝气量保持在30L/min,对屠宰废水的CODcr,NH4+-N,TP,TKN(凯氏氮)去除效果进行分析研究。实验结果表明,CODcr,NH4+-N,TP和凯氏氮去除率分别可达90%,95%,70%,90%,各项出水指标均达到了农田灌溉的标准。     

广东省屠宰场猪群PRRSV感染状况调查及基因测序分析

为了解广东省育肥猪群猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)携带情况,2019年在广东省43个生猪屠宰场,采集临床健康生猪淋巴结样品840份,运用商品化荧光定量RT-PCR试剂盒进行PRRSV核酸检测。设计PRRSV ORF5基因引物,选取部分阳性样品进行RT-PCR,测序后进行基因序列分析。结果显示:840份样品的PRRSV阳性率为17.02%,其中美洲型为14.29%,欧洲型为2.73%;成功获得15份样品的ORF5基因序列,其中12株为美洲型,3株为欧洲型;美洲型毒株中包含:JXA1-like毒株5株,GM2-like毒株3株,NADC30-like和VR2332毒株各2株;美洲型毒株基因相似度为87.5%～99.6%,欧洲型为90.2%～90.4%。对美洲型毒株的ORF5基因编码的氨基酸进行分析,发现检测到的不同亚群毒株各个功能区存在广泛的、显著的变异。结果表明,广东省屠宰场猪群的PRRSV隐性带毒率较高,且毒株复杂多样,以美洲型毒株为主,且已存在欧洲型毒株。建议落实并强化规模化猪场生物安全措施,加强流行病学监测,继续推动PRRSV净化工作。     

肉鸡屠宰废水及下脚料综合处理的研究

该文利用以UASB和接触氧化法技术为核心的工程处理设施和生物综合治理两项关键技术,分别对肉鸡屠宰场废水及下脚料进行综合治理研究。结果表明：工程处理设施可使屠宰场废水及下脚料的COD、BOD₅、SS和油类去除率分别达96.8%、99.6%、99.6%和99.4%。各项指标均达到GB8978-1996《污水综合排放标准》一级和GB13457-92《肉类加工工业水污染物排放标准》禽类屠宰加工一级标准,减少处理费25%。通过生物综合治理措施处理后的水质也达到上述标准,处理费用可以减少85%。     

RESEARCH ON THE SLAUGHTERHOUSE WASTEWATER TREATMENT IN A GAS-LIQUID-SOLID FLUIDIZED BED BIOREACTOR

The process of treating slaughterhouse wastewater in a gas-liquid-solid fluidizedbed bioreactor is studied,and the factors of affecting reactor performance are a nalysed in this pa-per.Some design parameters and experiences are obtained through the pilot experiment.