An Investigation of Calf Carcass Contamination by Escherichia coli from the Gut Contents at Slaughter

The degree of carcass contamination at slaughter of three groups of calves (a total of 36 animals) was studied and the O-antigen types of Escherichia coli found on the carcass surface and in rectal contents were determined. In one-third of the animals E. coli strains found on the surface of a carcass belonged to the same O-serotype as those found in the rectal sample of the same calf. Nearly all the O-serotypes found on the carcasses were also found in the rectal contents of at least one calf, showing that cross-contamination of carcasses had occurred. The E. coli isolated from the rectal contents were all resistant to at least one antibacterial agent.     

实验用生物样品的啮齿类微生物污染的检测管理

实验用生物样品在生物医学研究中有着广泛的应用.生物样品的微生物污染可危及实验动物设施的生物安全以及对动物实验研究造成负面影响.因此在将生物样品接种到啮齿类动物之前,要对其进行检测以确保无啮齿类动物传染性病原体的污染.因为检测技术和经济上的限制和局限性,不可能对所有的啮齿类动物传染性病原都进行检测.本文依据科学文献、笔者的经验以及专家的意见,尝试着去阐述如何建立一个有效可行的生物样品微生物污染检测计划.笔者建议对一些重要的微生物进行检测,并简要综述了选取这些微生物的理由即它们对科研、实验动物生物安全以及职业健康安全的影响.     

Risk Factors for Whole Carcass Condemnations in the Swiss Slaughter Cattle Population

We used meat-inspection data collected over a period of three years in Switzerland to evaluate slaughterhouse-level, farm-level and animal-level factors that may be associated with whole carcass condemnation (WCC) in cattle after slaughter. The objective of this study was to identify WCC risk factors so they can be communicated to, and managed by, the slaughter industry and veterinary services. During meat inspection, there were three main important predictors of the risk of WCC; the slaughtered animal''s sex, age, and the size of the slaughterhouse it was processed in. WCC for injuries and significant weight loss (visible welfare indicators) were almost exclusive to smaller slaughterhouses. Cattle exhibiting clinical syndromes that were not externally visible (e.g. pneumonia lesions) and that are associated with fattening of cattle, end up in larger slaughterhouses. For this reason, it is important for animal health surveillance to collect data from both types of slaughterhouses. Other important risk factors for WCC were on-farm mortality rate and the number of cattle on the farm of origin. This study highlights the fact that the many risk factors for WCC are as complex as the production system itself, with risk factors interacting with one another in ways which are sometimes difficult to interpret biologically. Risk-based surveillance aimed at farms with reoccurring health problems (e.g. a history of above average condemnation rates) may be more appropriate than the selection, of higher-risk animals arriving at slaughter. In Switzerland, the introduction of a benchmarking system that would provide feedback to the farmer with information on condemnation reasons, and his/her performance compared to the national/regional average could be a first step towards improving herd-management and financial returns for producers.     

Microbiological Contamination of Hospital Air: I. Quantitative Studies

The levels of airborne contamination in various areas of two hospitals were determined during a 15-month sampling period, using Casella and Andersen volumetric samplers. Based on nearly 5,000 samples, the mean count per ft³ ranged from 4.5 in obstetric-gynecology delivery rooms to 72.4 in waste-handling areas. The mean count for the entire hospital environment was on the order of 20 contaminants per ft³; 48% were associated with particles >5 μ diam, 30% with particles between 2 and 6 μ diam, and 22% with particles <2 μ diam. The airborne contamination was influenced by traffic, activity, ventilation considerations, and gross surface contamination, but not markedly by seasonal changes. When suitable control measures were implemented, the level of contamination could be diminished and kept low.     

Microbiological Contamination of Hospital Air: II. Qualitative Studies

Over 10,000 airborne microorganisms, isolated from various areas of two hospitals, were characterized according to colonial and microscopic morphology and certain physiological reactions, including penicillin resistance and hemolysis. On the basis of all isolates examined during a 15-month period, 42.6% were gram-positive cocci, 19.2% were gram-positive rods, 14.0% were gram-negative rods, 17.1% were molds, 2.2% were actinomycetes, 1.2% were yeasts, and the remainder were assorted diphtheroids and coccobacillary types. The distribution of types varied according to hospital area, locations within a given area, and level of gross airborne contamination, but did not vary significantly with season of the year. There appeared to be some relationship between contaminant particle size and type of organism associated with the particle. Distribution of penicillin-resistant types differed markedly in different hospital areas, with proportions ranging from 21.4% in surgery areas to 4.3% in incinerator rooms. Of all gram-positive cocci isolated, 34.9% were hemolytic, and 16.4% were penicillin-resistant.     

Microbiological Evaluation of Protected Environments During Patient Occupancy

Microbiological monitoring has been conducted in two life island (LI) units and two laminar airflow (LAF) rooms while they were occupied by patients undergoing cancer chemotherapy. There were only 5 organisms per 1,000 ft(3) of air sampled in LAF rooms, 31 organisms in LI units, and over 3,000 organisms in regular hospital rooms. None of the floor samples obtained from hospital rooms was sterile, compared to over 70% in LAF rooms. The rate of deposition of organisms onto settling plates was one organism per 4.5 hr in LAF rooms compared to one organism per 0.08 hr in hospital rooms. Potential pathogens were isolated much more frequently from environmental samples obtained from hospital rooms than from LI units or LAF rooms. Two sites of persistent contamination arose in the LAF rooms: the vinyl tile flooring and the water supply system. Over half of the potential pathogens cultured from the protected environment units were cultured initially from the patients who occupied the units.     

Biohazard Hood to Prevent Infection During Microbiological Procedures

A microbiological hood was designed to reduce the danger of airborne infection of laboratory workers. The hood uses absolute filters to deliver sterile air in a laminar flow to the work area. An air curtain across the hood opening permits easy access but separates the worker from aerosols produced in the hood, and protects material inside the hood from contamination by room air. Tests with bacterial and viral aerosols showed that the air curtain is at least 99.96% effective in preventing airborne particles from entering the work area.     

Contamination of Sputum Induction Equipment During Patient Usage

Sputum induction equipment was evaluated for its capacity to become contaminated by patients harboring Mycobacterium tuberculosis. The mouthpiece, goose-neck, and 10% NaCl solution were found capable of being contaminated by tuberculous patients. Two per cent glutaraldehyde was shown to be an effective means of decontamination. This study indicates that the entire induction apparatus must be cleaned and decontaminated between patients.     

Microbiological Contamination of Carcasses Related to Hygiene Practice and Facilities on Slaughtering Lines

The purpose of the study was to investigate the association between the hygienic practice of slaughterhouse workers and the microbiological contamination level of carcasses. In 5 Finnish slaughterhouses the workers’ hygienic practice was observed and the carcasses were sampled by the swabbing method. The overall means (log10 cfu cm−2) of the aerobic plate count in pork and beef carcasses were 3.23 and 2.65, respectively. Hygienic practice was found to be associated with the carcass contamination level, especially the disinfection frequency. In those slaughterhouses, where the disinfection frequency was low, the contamination level of carcasses was high. Designing slaughtering lines so as to make hygienic working possible is evidently very important. However, the enforcement of hygienic practice, such as the regular disinfection of working tools, is also important in reducing the microbiological contamination of carcasses.     

The Effect of Mixing Entire Male Pigs Prior to Transport to Slaughter on Behaviour,Welfare and Carcass Lesions

Research is needed to validate lesions recorded at meat inspection as indicators of pig welfare on farm. The aims were to determine the influence of mixing pigs on carcass lesions and to establish whether such lesions correlate with pig behaviour and lesions scored on farm. Aggressive and mounting behaviour of pigs in three single sex pens was recorded on Day −5, −2, and −1 relative to slaughter (Day 0). On Day 0 pigs were randomly allocated to 3 treatments (n = 20/group) over 5 replicates: males mixed with females (MF), males mixed with males (MM), and males unmixed (MUM). Aggressive and mounting behaviours were recorded on Day 0 at holding on farm and lairage. Skin/tail lesions were scored according to severity at the farm (Day −1), lairage, and on the carcass (Day 0). Effect of treatment and time on behaviour and lesions were analysed by mixed models. Spearman rank correlations between behaviour and lesion scores and between scores recorded at different stages were determined. In general, MM performed more aggressive behaviour (50.4 ± 10.72) than MUM (20.3 ± 9.55, P < 0.05) and more mounting (30.9 ± 9.99) than MF (11.4 ± 3.76) and MUM (9.8 ± 3.74, P < 0.05). Skin lesion scores increased between farm (Day −1) and lairage (P < 0.001), but this tended to be significant only for MF and MM (P = 0.08). There was no effect of treatment on carcass lesions and no associations were found with fighting/mounting. Mixing entire males prior to slaughter stimulated mounting and aggressive behaviour but did not influence carcass lesion scores. Carcass skin/tail lesions scores were correlated with scores recorded on farm (r_skin = 0.21 and r_tail = 0.18, P < 0.01) suggesting that information recorded at meat inspection could be used as indicators of pig welfare on farm.     

Assessment of Welfare Issues During Traditional Slaughter of Goats in Pretoria,South Africa

Goats are traditionally slaughtered to celebrate marriages and births, venerate ancestors, address personal problems, or perform a ritual during funerals. The objective of this study was to assess nonhuman animal welfare issues associated with the traditional slaughter of goats in and around Pretoria, South Africa. Participatory research methods were used to interview 105 respondents. Four of those interviewed were visited to observe the slaughter process. The most common method of transport was a vehicle (47%), followed by transport on foot (30%). The distance traveled (68%) was usually less than 10 km, and in all cases, it was less than 50 km. The most common (57%) method of restraining goats during transport was tying all 4 legs together. During slaughter, assistants held the head and legs of the goat (55%). Prior to slaughter, the majority of goats were tied under a tree (66%). In total, 97% of the goats were slaughtered within 24 hr, and no stunning was performed. In this study, animal welfare problems were widespread. Research should be undertaken to find practical ways to address animal welfare issues during traditional slaughter.     

Contamination of the Deep Tissues of Carcasses by Bacteria Present on the Slaughter Instruments or in the Gut

Possible routes by which bacteria might reach the deep tissues of carcasses were tested by placing genetically 'marked'strains of Escherichia coli, Clostridium perfringens or Bacillus thuringiensis on slaughter instruments before use and examining deep tissue samples for their presence post mortem . Bacteria present on the captive bolt pistol were recovered from the spleens of beef cattle and those placed on the pithing rod were found in both spleen and muscle of the flank and neck. Bacteria from the throat cutting ('stick') knife were isolated, on different occasions, from the heart, lung, spleen, liver and kidneys of sheep though rarely from their muscles. Orally administered bacteria were found in the spleen and lung, but not the musculature, of pigs.     

Microbiological and Chemical Changes in Lean Wiltshire Bacon During Aerobic Storage

Total microbial growth and chemical changes in aerobically stored bacon lean were found to fall into 2 phases. Phase 1: there was an increase in total microbial load to c . 10⁹/g, during which most of the nitrate was broken down and there was an accumulation of nitrite. Phase 2: the microbial load increased further to c . 10¹⁰/g and during this time most of the accumulated nitrite was broken down to unknown products, so that at the end of the experiments most of the nitrate and nitrite had disappeared from the bacon.
The most important types of micro-organisms isolated from the bacons were Micrococcus , yeasts, Vibrio, Acinetobacter, Alcaligenes and Arthrobacter-Corynebacterium. The latter 3 types appeared to be associated with phase 2 changes.     

Techniques for Contamination Assessment During Drilling for Terrestrial Subsurface Sediments

Details about the procedures for drilling a ca. 150 m long drill core in a terrestrial setting under contamination controlled conditions are presented. Different to previous studies we only used commercially available drilling equipment to reduce the cost of operation significantly. The goals were (1) to minimize, (2) to monitor and, if possible, to quantify the contamination of the recovered sediments, and (3) to identify the different sources of contamination. Both the potential contamination of the sample material by surface microorganisms and non-indigenous material was assessed. To estimate the infiltration of drill mud into the core, fluorescent microspheres, having about half the size as microorganisms, were added to the mud. The drilling technique used was mud rotary drilling. With the exception of the very beginning of the drilling operations, the drill mud was devoid of any allochthonous hydrocarbons potentially derived from the drilling equipment or drill additives, and its biomarker composition reflected the varying organo-facies that were penetrated. Due to the lack of allochthonous hydrocarbons in the drill mud, its infiltration into the sediment cannot be traced by organic geochemical biomarker analysis. Microspheres proved to be a sensitive tool for the assessment of infiltration of drill mud into the core. The concentration of microspheres in the drill mud decreased continuously during the drilling, most probably caused by seepage of mud through leaks and attachment of spheres to the surface scum in the mud pit. Microscopic enumeration of the microspheres showed great variability in the depth of penetration of mud into the core, apparently unaffected of lithology. The sampling of the core material in the laboratory was carried out inside an anaerobic chamber. Several techniques for subsampling were used, according to sediment properties. The overall results indicate that, if strict contamination control protocols are employed, it is possible to recover uncontaminated samples at reasonable cost with commercially available drilling equipment.     

Trends in Basalt and Sediment Core Contamination During IODP Expedition 301

Perfluorocarbon tracers (PFTs) are used during cruises of the Ocean Drilling Program (ODP) and Integrated Ocean Program (IODP) to measure sample contamination with drilling fluid. Drilling fluid is supplied with a constant PFT concentration that can then be detected and quantified in sediment and basalt core samples. During IODP Expedition 301, we used washing (2×) and flaming to effectively remove PFT from the exterior of basalt rocks. Near-complete removal from the exterior allowed us to demonstrate that the interior of basalts was only minutely, if at all, contaminated with drilling fluid. We examined horizontal and vertical trends in sediment core contamination. Contamination decreased greatly between the core exterior to halfway along the core radius, and slightly from halfway to the center of cores, and was generally very low in halfway and center portions. Clay cores were, on average, more contaminated than cores with fine sand. Contamination was typically highest in the two uppermost sections (sections 1 and 2) and lower below (sections 3–5). There was no relationship between depth of core origin and contamination. To determine mechanisms of contamination in halfway and interior parts of cores, we estimated the diffusive flux of PFT from the core liner towards the core center. Based on conservative estimates, we concluded that diffusion did not account for any of the PFT measured in halfway and interior parts of cores in this study. Any measurable PFT concentrations in halfway and center parts of cores were caused by advection.     

Reindeer reduce biomass of preferred plant species

Abstract. Reduced weights in reindeer that graze in pastures with high reindeer densities have raised the question if coastal summer pastures are modified by grazing. To evaluate this, the impact of reindeer grazing on standing crop was measured by the plant intercept method inside and outside grazing exclosures in the understorey of a coastal mountain birch forest in northern Norway. The understories of coastal birch forests are dominated by vascular plants and are important summer pastures to reindeer. Based on the literature, we made a priori categorization of the vascular plant species into functional groups of preferred forage, less preferred forage and forage of unknown value to reindeer. Intercept frequency was measured within the same plots on three occasions in the summer of 1996. At the end of the grazing season, total standing crop was 33% lower in open plots compared to plots protected by exclosures. However, the reduction varied between the functional groups, with only preferred forage plants being significantly reduced in standing crop (by 49%). Results suggest that reindeer have a strong annual impact on most of the preferred forage species. However, some of the preferred graminoids are tolerant of grazing and dominate the understorey despite decades of high grazing pressure. We suggest that current grazing pressure is favouring the establishment of a few grazing tolerant graminoids, and that this reduces the forage plant variability. The results are discussed in relation to the grazing optimization hypothesis and the potential importance of plant variability for pasture quality.     

Screening of Enterobacterial Contamination During Gelatin Production and its Effect on Pharmaceutical Grade Gelatin

Summary Gelatin, an animal protein derived from collagen has many industrial applications; mainly in food and pharmaceutical products. In this study, enterobacterial contamination of gelatin during different stages of its manufacturing was examined. Since gelatin is extracted in the form of liquor by hot water treatment of ossein and undergoes a complex series of processing stages before being finally blended and packaged off as dry gelatin product, contamination at any stage affects the quality of the final product. In total, 142 samples of gelatin were analysed for the presence of enteric bacteria, which were obtained from different stages of gelatin processing. The Enterobacteriaceae-positive samples were processed and these enterobacterial species were isolated and identified as Proteus mirabilis, Serratia marcescens, E. coli, Salmonella typhi, Klebsiella oxytoca, Klebsiella pneumoniae, Shigella flexneri and Serratia liquefaciens. These were tested for gelatinase activity. The eight species producing maximum gelatinolysis were selected and protease zymography was performed using 1% (w/v) gelatin as a substrate in 7.5% (w/v) acrylamide gel and their molecular weights were determined. The effect of these bacteria on the quality of gelatin was assessed chromatographically in terms of change in amino acid content of gelatin broth inoculated by these species, which showed a marked change with length of incubation. Since these enteric bacteria possess pathogenic properties, some of them are gelatinolytic and also have a significant effect on the quality and amino acid content of gelatin, they are of great concern both for the manufacturers as well as for the consumers.     

Artificial insemination of Reindeer (Ragifer tarandus)

Semen collected from reindeer bulls in an artificial vagina was used for the artificial insemination of 16 reindeer cows: two with undiluted semen, five with diluted semen and nine with frozen semen. The two cows which received undiluted semen gave birth to normal calves 217 days later. The other cows returned to oestrus 23.5 days (mean) after insemination and subsequently calved, having been served by a fertile bull.