Kinetics of hydrophobic organic contaminant extraction from sediment by granular activated carbon.

Ex situ solid phase extraction with granular activated carbon (GAC) is a promising technique to remediate contaminated sediments. The methods' efficiency depends on the rate by which contaminants are transferred from the sediment to the surface of GAC. Here, we derive kinetic parameters for extraction of polycyclic aromatic hydrocarbons (PAH) from sediment by GAC, using a first-order multi-compartment kinetic model. The parameters were obtained by modeling sediment-GAC exchange kinetic data following a tiered model calibration approach. First, parameters for PAH desorption from sediment were calibrated using data from systems with 50% (by weight) GAC acting as an infinite sink. Second, the estimated parameters were used as fixed input to obtain GAC uptake kinetic parameters in sediment slurries with 4% GAC, representing the ex situ remediation scenario. PAH uptake rate constants (kGAC) by GAC ranged from 0.44 to 0.0005 d(-1), whereas GAC sorption coefficients (KGAC) ranged from 10(5.57) to 10(8.57) L kg(-1). These values are the first provided for GAC in the presence of sediment and show that ex situ extraction with GAC is sufficiently fast and effective to reduce the risks of the most available PAHs among those studied, such as fluorene, phenanthrene and anthracene.

[Experiences of a veterinary meat inspector. I]. / Ervaringen van een herkeuringsdierenarts. I.

Re-inspection of animals for slaughter is based on article 13 of the Meat Inspection Act, under which re-inspection is defined as a new inspection. This article describes the re-inspection of 94 animals for slaughter according to existing regulations and instructions. In 45% of the cases, the veterinary meat inspector had doubts about the decisions taken in the first inspection or about the grounds mentioned as reason for the decision to reject or condemn the animal/carcass. The verdict of the first inspection was changed when there were positive results for tests for agents that slow bacterial growth, positive results for tests for bacteria, abnormal consistency, and cysticercosis. It was concluded that, in the interests of uniformity all the investigations stipulated in the Inspection Regulations should be carried out during the first inspection and that all reasons for condemning an animal/carcass should be given. In addition, all veterinary meat inspectors involved should be told the outcome of the second inspection and of any omissions discovered during this inspection.

[Experiences of a veterinary meat inspector. II]. / Ervaringen van een herkeuringsdierenarts. II.

A number of unusual or repeat inspections are described. These inspections took place in relation to investigations for the presence of agents that slow bacterial growth (New Netherlands Kidney Test), condemnation of the animal/carcass for more than one reason, investigations to detect the presence of hormones and beta-antagonists, severe abscesses in the spleen, absence of the entire carcass, special emergency slaughter, deep cuts in the kidney, and botulism. Emphasis is placed on the importance of veterinary meat inspectors being closely involved in the rejection or condemnation of animals for slaughter.

[Taxus baccata poisoning in lambs and meat inspection]. / Intoxicatie van lammeren door Taxus baccata en vleeskeuring.

Yew (Taxus baccata) poisoning in lambs: meat control twenty-two poisoned lambs were slaughtered at a special slaughterhouse. Yew intoxication was diagnosed on the basis of the anamnesis and the presence of yew needles in the rumen. Data from the literature concerning the toxicity of yew and some (traditional) uses of yew are reported. The symptoms and post-mortem findings in animals and humans are discussed, together with the poorly effective treatment of yew poisoning and preventative measures. The outcome of the meat inspection is explained on the basis of current and new regulations (Regulations and Guidelines Governing the Inspection of Meat 91/497/EEG). A reliable and recognized method for the detection of taxins is required.

[Botulism in cattle and meat inspection]. / Botulisme bij runderen en vleeskeuring.

Three animals suspected of the presence of botulism, which were found to be infected with Clostridium botulinum type D were slaughtered in a special slaughter-house. The presence of C. botulinum in cattle and the decision reached by the meat inspection are discussed. Central registration of all cases of botulism observed in The Netherlands is advocated.

[Bacteriological study of fresh, preserved, damaged and contaminated pig spleens]. / Bacteriologisch Onderzoek van verse, bewaarde, beschadigde en verontreinigde varkensmilten.

Since the amendment of the Meat Inspection Act as on January 1, 1979, only the spleen is used as an indicator organ to detect bacteraemia in bacteriological examinations. The spleens should be handled carefully during slaughter, inspection, storage, transportation and laboratory testing in order to prevent false positive results of bacteriological examination caused by errors of inoculation, damage, contamination and unduly high storage temperatures. Bacteria could not be isolated from 86.2 per cent of 399 directly examined spleens of clinically normal pigs. Positive cases may have been due to acute bacteraemia in which the primary source of infection escaped notice, transient bacteraemia or errors of inoculation. Moreover, examination of damaged or contaminated spleens and spleens stored at too high temperatures showed that the usual method of sterilisation of the splenic surface singing is inadequate in some cases. In view of the fact that storage at 4 degrees C was not found to affect the results of bacteriological examination, the spleens which are to be examined should be intensively chilled immediately after slaughter.

[Microbiological reference values for food products]. / Microbiologische referentiewaarden voor voedingsmiddelen.

This article describes the procedure recommended for setting up the ranges of microbiological reference values for foodstuffs, to be used in the microbiological inspection procedures of the integrated quality guarantee system. Such reference values should be based on 'Good Management Practices' (GMP) programmes. Strategic intervention, through control of the production line, in order to correct the contraventions evident in the GMP programme, is the first necessity in guaranteeing microbiological quality. Also, the hygienic/microbiological supervision of end products remains indispensible, so that the effectiveness of prevention procedures can be verified. In this way, errors which may have previously escaped detection can be found and eliminated. It is emphatically pointed out that only through cooperation between experts of various disciplines involved directly in animal health, working under one 'umbrella' organisation, can the best guarantee of efficacious protection be offered to the consumer.

[The hygienic status of meat transport vans]. / Een onderzoek naar de hygiënische gesteldheid van vleestransportauto's.

Meat transport vans were sampled using impression surfaces of violet red bile glucose agar (VRBG agar; in 1978) and plate count agar (PC agar) contained in so-called Rodac plates (during the period from 1979 to 1982). So-called hygienograms of each van were recorded. At the same time, scrapings from the vans were examined for contamination by Salmonella. The majority of meat vans were only slightly contaminated with Enterobacteriaceae. The state of hygiene of approximately fifty per cent of the meat vans examined with plate count agar was inadequate initially. However, considerable improvement occurred during the course of the investigations. Seasonal effects were merely limited. Moreover, there was not found to be any relationship between the appearance of scrapings positive for Salmonella and the state of hygiene of the transport vans. Systematic bacteriological examination of meat transport vans is considerably hampered in practice by the ambulatory character of meat transport.

Butcher's knife wounds, are they really so contaminated?

The aerobic flora found in wounds caused by butcher's knives was compared with the flora in similar wounds caused by other sharp objects. Gram-positive bacteria predominated in the wounds caused by butcher's knives while the other cuts were colonised predominantly by Gram-negative flora. Identically low concentrations of colonising bacteria were found in both groups. The qualitative analysis provided no bacteriological argument for treating a wound from a butcher's knife as being more infected and therefore produced no contraindication for the primary reconstruction of damaged structures (i.e., tendons and nerves) together with skin closure in this type of injury.

[Salmonella's in butcher's block scrapings from butcher's shops (author's transl)]. / Salmonella in hakblokafkrabsels uit slagerijen.

Samples of scrapings from butcher's blocks in butcher's shops were examined weekly for the presence of Salmonella throughout a period of twelve years (from 1967 up to and including 1978). At the same time, a so-called hygienogram was made of each sampled butcher's shop using the agar-impression method. Of the total number of 6,874 samples studied, 279 (4.06 per cent) were positive for Salmonella. From 1967 to 1971, the proportion of contaminated samples gradually decreased from 2.14 to 0.90 per cent. This proportion increased again from 1971 to 8.50 per cent in 1976, to be followed, however, by a marked reduction to 2.96 per cent in 1978. This undulation was also observed when meat-vans were studied by a similar method during the same period. There were only limited seasonal effects on the contamination of samples of scrapings with Salmonella. As was also the case with the study of meat-vans, the three sero-types most frequently isolated were S. typhimurium, S. panama, and S. brandenburg. These serotypes were also isolated several times from samples such as those of minced meat. It is concluded that an unmistakable route of contamination is maintained by meat-vans from the slaughter-houses to butcher's shops. Therefore, strict enforcement of hygienic procedures is indicated. In view of this fact, the supervisory and controlling duties of meat inspection services are stressed.

[Salmonella in scrapings from meat vans (author's transl)]. / Salmonella in afkrabsels uit vleestransportauto's.

Throughout a period of thirteen years (from 1965 to 1977 inclusive), samples of scrapings from meat vans were examined weekly for the presence of Salmonella. Samples were collected from the vans on the precincts of the public slaughter-house in Groningen. Of the total number of 6,751 samples studied, 213 (3.16 per cent) were positive for the presence of Salmonella. During the period from 1965 to 1970, the proportions of contaminated samples gradually decreased from 4.85 to 1.11 per cent, whereas it increased again up to 6.33 per cent in 1976. There was a limited seasonal effect on contamination of the scrapings with Salmonella, the highest rates of contamination being recorded during the period from May to October inclusive (warm and humid season). The serotypes most frequently isolated on examination were S. typhi-murium, S. brandenburg and S. panama. These serotypes were also constantly found to be present in other material such as samples of minced meat and scrapings from slaughter-house and butcher's shops. It is concluded that contaminated meat vans are a factor in maintaining cycles of contamination by Salmonella organisms in a rather large area.

[Sterilization of plastic culture boxes by formaldehyde vapour (author's transl)]. / Sterilisatie van plastic-cultuurdoosjes door middel van formaldehydedamp.

Various experiments showed that plastic culture boxes may be sterilized by formaldehyde vapour in an exsiccator. Detectable quanties of formaldehyde were no longer found to be present when the dishes had been stored at room temperature for 24 hours after sterilization. A striking fature in these experiments consisted in the fact that colonies failed to grow on those agar plates, the surfaces of which had been in contact with formaldehyde vapour. The dishes used should be meticulously cleaned as studies showed that complete sterilization was not achieved when bacteria were present in or on agar. When Petri dishes cleansed in alcohol and then sterilized were used in assessing aerobic bacterial counts in minced meat by the mixed plate technique, significantly higher average numbers of colonies were recorded than was the case when commercially available sterilized Petri dishes were used. When the streak plate method was adopted, however, no significant differences were observed. When all the required manoeuvres are performed with meticulous care, the method is a practicable one ensuring that plastic culture boxes may be used again several times.

[Effect of the diluent on the aerobic bacterial count in raw minced meat and similar meats (author's transl)]. / De invloed van de verdunningsvloeistof op het aërobe kiemgetal in rauw gehakt en overeenkomstige vleesprodukten

A report on the changes in the aerobic bacterial count in commercial minced meat, which appear when samples, decimally diluted with 0.85 per cent sodium chloride or with 0.85 per cent sodium chloride plus peptone (peptone physiological saline solution, p.ph.s.s.) are stored at room temperature for some time. When the higher dilutions (10(5) to 10(7) inclusive) were stored for periods of thirty minutes and more, significantly higher counts were recorded on using p.ph.s.s. and significantly lower counts were observed on using sodium chloride. Significantly higher counts were produced, however, when the two diluents were used following storage of the lowest dilution (10(1)) for a similar period. The dilutions have to be mixed again after each period of storage. The presence of "sublethally injured" bacteria in commercial minced meat is discussed. These bacteria may recover when a diluent having a sufficiently protective effect is used. Substances from the natural substrate are probably still active at the lowest dilution. A number of the injured bacteria which fail to multiply when the pour-plate method is used, will probably be able to produce colonies when the streak-plate method is adopted as more oxygen will be present in this case. Even when a rapid procedure is used in examining the samples (mixed agar method), the average number of colonies produced on using sodium chloride will be significantly smaller than that produced when p.ph.s.s. is used.