Planning, organisation and administration of veterinary public health activities.

Advice is given on how to set up a veterinary public health programme, drawing on recommendations of the World Health Organisation (WHO). Trichinellosis control is used as an example of planning procedures.

Veterinary public health activities aimed at prevention of intoxications by chemical residues in foods of animal origin. Suggestions for inspection programmes.

Practically all today's raw agricultural products have been treated or exposed to one or more agricultural chemicals or veterinary products, in order to increase food production. A tremendous amount of work has been done by veterinarians in coping with diseases and health risks due to microorganisms, parasites and other agents of biological origin. There is no doubt that veterinary services, research and educational institutions have a long and successful tradition also in dealing with problems of chemicals associated with animal and food production, processing, transportation, storage and distribution. Due to the increasing quantity and large numbers of chemicals now used in animal production and related fields, it has however become indispensable to broaden and intensify the education and training of veterinarians, as well as to ensure their participation in all sectors of this field. Veterinarians should be fully involved in the surveillance, prevention and control of intoxications by chemical residues. They are well qualified to do this. They are working continuously in the areas where exposure to animals and food may occur, possess adequate knowledge of the routes of entry of such chemicals into food chains, the fate of their residues, the health hazards involved, as well as of the toxicology, pathology, pathophysiology, and food hygiene and technology. Residues present an enormous challenge for surveillance, prevention and control in agriculture, food processing and related activities.

The state of food hygiene and foodborne diseases: requirements for the future.

The current world situation of foodborne diseases is reviewed with an analysis of the factors responsible for their occurrence in both developed and developing countries. Strategies to solve the problems associated with food hygiene are also reviewed with special attention to the most recent approaches identified and worked out by the main institutions concerned. Specific suggestions are given for more effective planning and implementation of future global food hygiene programmes.

[Examination of muscular and liver tissues of fish for the presence of aflatoxin B 1]. / Vysetrování svaloviny a jaterní tkáne ryb na prítomnost aflatoxinu B1.

A method of the determination of aflatoxin B1 in the liver and muscular tissue of carp is described, enabling the capture of 50 ng in one kilogram. Extraction and purification were followed by thin-layer chromatography and by identification by means of ultraviolet light with simultaneous comparison with the standard. The examination was performed with 44 samples coming from healthy table carp from the Pohorelice farm of the State Fisheries National Corporation. None of the 44 the Pohorelice farm of the State Fisheries National Corporation. None of the 44 samples contained aflatoxin residues.

[Analysis of aflatoxin Ml in fresh milk]. / Pruzkum prítomnosti aflatoxinu M1 v Mléce z prvovýroby.

Seventy-seven samples of cow's milk were examined by the method after Stubble-field (1979) for the presence fo aflatoxin M1; 34 of these samples came directly from farms and 43 were mixed, being taken from tank trucks. Aflatoxin M1 was found in five samples from farms and in none of the mixed samples. In the positive cases, concentrations were determined semiquantitatively and were found to range from a trace amount up to 0.38 microgram aflatoxin M1 per litre of milk. Hence the aflatoxin M1 concentration levels never exceeded tha admissible limit value.

[The occurrence of zearalenone in domestic grains]. / Výskyt zearalenonu v tuzemských zrninách.

The occurrence of zearalenone had not been tested n Czechoslovakia; out of a number of analytic procedures for the determination of this mycotoxin in grains and some feed mixtures, the method described by Mirocha et al. (1974) was chosen for this study. The tests were performed with 61 samples of grain and 22 samples of other feeds. In barley 58.3% of the samples were positive in the range from 0.19 to 0.82 micromol.kg-1 in wheat 46.4% of samples in the range from 0.19 to 0.57 micromol. kg-1, in maize 6.7% of samples, containing 0.33 mumol.kg-1. Oat samples contained no zearalenone. The positive findings in the samples of the commercial mixtures COS 1, COS 2, SOL and KPB ranged from 0.19 to 0.32 mumol. kg-1. Zearalenone concentrations above 0.32 mumol. kg-1 were found in seven samples of wheat, in four samples of barley, in one sample of maize and in one sample of complete feed mixture for early-weaned piglets. The described method is recommended for screening examination of grains for zearalenone in Czechoslovakia.

[Investigation of the presence of aflatoxins B1 and M1 in meat products]. / Pruzkum prítomnosti aflatoxinu B1 a M1 v masných Výrobcích.

Sixty-four samples of thirty-one kinds of meat products were examined by the chromatographic method with the use of a thin layer of silica gel. No aflatoxin B1 was revealed in any of the samples. Positive findings of aflatoxin M1 were obtained in three products: liver pasty, smoked rolled shoulder, and in the Spis sausage. The values found in semiquantitative evaluation were lower by 2.0 to 2.5 orders than the proposed admissible aflatoxin concentration in foods for adults in the Czech Socialist Republic (5 micrograms kg-1).

[Lead content of muscles and liver of cattle]. / Obsah olova ve svalovine a v játrech skotu.

182 samples of bovine musculature and 183 samples of bovine liver obtained from the sanitary slaughters in the North Moravian region, mostly at Frýdek-Místek, over the February and March 1978, were examined for the lead content by the method of atomic absorption spectrophotometry. The lead content in the examined samples of musculature ranged from 0 to 0.80 mg per kg (average value 0.28 mg per kg) and in the examined samples of liver from 0 to 1.23 mg per kg (average value 0.39 mg per kg); in 2.2 per cent of liver samples the level of lead was higher than 1.0 mg per kg. The highest admissible level of lead in bovine musculature and liver is being discussed, and the tolerated level of weekly intake by adult persons.

[Chlortetracycline residues in the meat of slaughter calves in relation to transmissible microbial resistance to antibiotics]. / Rezidua chlortetracyklinu u jatecných telat ve vztahu k prenosné mikrobiální rezistenci na antibiotika.

The occurrence of chlortetracycline residues in the meat of slaughter calves in 62% herds under study (the additive of the medicated premix AUREOVIT to feed without observing the withdrawal times) did not influence significantly the Gram-negative resistant and R+ microflora isolated from the same material, in comparison with control herds that were administered no antibiotics. Neither was the spectrum of donors and transferring R plasmids influenced significantly nor the incidence of different resistance determinants. The effect of chlortetracycline addition to feed was negative (at P = 0.05) only in the occurrence of R+ microflora isolated from stable environment where the slaughtered calves had been housed.

[Testing the screening method for assaying ochratoxin in grains]. / Overení screeningové metody na zjistování ochratoxinu v zrninách.

To detect ochratoxin in grains and some feed mixtures the method described by Nesheim et al. (1973) was chosen out of a large number of analytical procedures. No ochratoxin was assayed in any of 41 samples (barley, corn, wheat, oats, complete feed mixtures, degraded straw) which were obtained from the current operation of feed-processing plants, did not contain any macroscopically detectable molds, were taken from storehouses with safe store conditions and they were evaluated by agricultural enterprises as safe. This method can be recommended to assay grains for ochratoxin in Czechoslovakia.

[Method for the simultaneous determination of aflatoxins B1 and M1 in the liver of slaughter animals]. / Výber metody pro soucasné zjistování aflatoxinu B1 i M1 v játrech jatecných zvírat.

The method used by Egmond et al. (1979) was chosen from a number of methods recommended for the determination of aflatoxins in raw materials of animal origin. This method is described in detail to facilitate its use in practice in cases of forced slaughters of animals suspected of aflatoxicosis. The sensitivity of the method for aflatoxin B1 and M1 is about 0.05 micrograms . kg-1. On the whole, 88 liver samples were examined for the presence of the aflatoxins B1 and M1. The samples had been obtained from the slaughtered pigs (52), bulls (23), cows (6), calves (5), and from deceased pigs (2). Positive findings were obtained in five of sixteen pork liver samples and in two of the tested five samples of calf liver. All of these animals were suspected of aflatoxicosis. At current slaughter, only one case of 36 examined pigs was found to be positive. Aflatoxin M1 was found more frequently than aflatoxin B1. However, the findings never exceeded the concentration of 100 ng . kg-1; this is less by 1.5 orders than the proposed tolerated concentration for adult animals (5 micrograms . kg-1).

[Study of the presence of sterigmatocystin in Czechoslovak grain]. / Pruzkum prítomnosti sterigmatocystinu v tuzemských zrninách.

Owing to its carcinogenic, hepatotoxic, nephrotoxic and dermatotoxic action, sterigmatocystine belongs to risky substances. Grains should be therefore examined for its content. A detailed description of a simple method for a current examination of grains for sterigmatocystine content is given and the method is recommended. Seventy-four samples were examined (24 samples of wheat, 19 samples of barley, 16 samples of maize, 10 samples of oats and 5 samples of rye) coming from the South Moravian, West Slovakian and East Slovakian regions from the 1980 and 1981 harvests. Only two barley samples and two maize samples were found to be positive: the maize samples contained about 50 micrograms and the samples of barley 200 and 400 micrograms of sterigmatocystine per 1 kg. One sample of wheat had a trace amount of the substance.

[Determination of aflatoxins in cheeses]. / Zjistování aflatoxinu v sýrech.

To investigate cheeses for the presence of aflatoxins we chose the very sensitive method of Tuinstra and Bronsgeest (1975) used for the determination of aflatoxin M1 in milk. The method was slightly modified and the presence of aflatoxins was determined in 54 samples of different cheeses. Aflatoxin M1 was found out in 24% of the investigated samples. Most of positive samples were found among the soft cheeses (53.8 3/4), then in processed cheeses (13.6%) and in hard cheeses (12.5%). Aflatoxin M1 was not found in the group of mouldy cheeses and Olomouc cake cheeses, which were investigated in a smaller range. Positive findings did not exceed concentrations of 10 ng per kg, i.e. they did not even reach the value of permissible concentration as proposed in the Czech Socialist Republic for foods (5 microgram per kg).

[Aanalysis of resistance and its transferability in microflora from primary meat production]. / Analýza rezistence a její transferability u mikroflóry z prvovýroby masa.

Resistance spectra and their transferability were studied in G- strains isolated from the primary production of meat by the method after Bohus (1974). Out of the set of strains, 93% were resistant, and out of these, 65% were multiresistant. Thirty-five per cent of the resistant strains were R plasmid donors. Of the two recipients, the laboratory strain of E. coli IHE Nx was significantly better. Among the 21 determined resistance spectra, the following were the most frequent: Tc, SmTcSu, and TcAm. Transfer of two to four, or even six, different plasmid types, mostly simple, was recorded from the two most frequent complex types of donor strain resistance: SmCmTcAmSu and SmTcAmSu. The determinants Tc and Am prevailed in the spectra of the transferring R plasmids, mostly as separate markers and only in 21 to 36% of cases in more complex types.

[Selection of screening methods for the detection of aflatoxins in animal feed]. / Výber screeingových metod pro zjistování aflatoxinu v krmivech.

Five different screening methods of the detection of aflatoxin B1 are compared as to their usability in ten feeds, feed concentrates, and complete feed mixtures. Method II, i. e. the author's modification of the method of Pons et al. (1973) was found to be the best for the highest number of different feeds. Aflatoxin B1-positive findings were obtained in samples of groundnut cake and protein concentrates a) for laying hens and b) for breeding pigs. No aflatoxins were detected in other feed samples: soya, sunflower, maize, fish meal, complete feed mixtures--table trout trout feed, carp stock feed, table carp feed, duckling fattening mixture.

[Study on the possible presence of aflatoxin B 1 in liver and muscle tissue of slaughter animals]. / Pruzkum mozné prítomnosti aflatoxinu B1 v játrech a svaloviné jatecných zvírat.

Seventy-seven samples of liver (from pigs, bulls, cows, broiler chickens, layers), twenty-eight samples of white muscle (from pigs, broilers, layers), and twenty-four samples of red muscle (from pigs, broilers, layers) were examined by the modified Jacobson method (Jacobson et al. 1971) for the contingent presence of aflatoxin B1. The samples came from healthy animals, part of them from animals fed non-traditional feed containing pig excrements. Positive findings were only obtained in two samples of pork liver, out of the total number of 30 samples. One sample came from pigs fed a ration containing 5% of pig excrements, the other from a traditionally fed pig. The amounts of aflatoxin B1 found in these two samples can be treated as trace quantities, since the concentration did not exceed 0.1 microgram per kg. In the samples of muscle and liver of the other farm animals, the chromatogram did not show the presence of spots which might resemble, in colour and position, the spots of aflatoxin B1.

[Selection of methods for the determination of aflatoxin presence in liquid milk]. / Výber metod pro zjistování prítomnosti aflatoxinu v tekutém mléce.

Seven methods, recommended for determining aflatoxins in liquid milk, were tested. Most of them were variously modified, mainly for the unavailability of some chemicals needed. Samples of liquid milk, normally prepared for direct consumption, were taken from the retail market (bottled and plastic-sacheted milk, durable milk in speical boxes). The authors describe in detail the two methods now appearing to be the best for current screening tests of market samples of liquid milk. Seventy samples of market liquid milk were tested by these methods, and 25 of them were found to be positive. However, there was no sample to contain as much aflatoxin as determined in the proposed admissible concentration for food.

[Detection of T-2 toxin in grains using thin layer chromatography with silica gel (TLC)]. / Prúkaz T-2 toxinu v zrninách chromatografií na tenké vrstve silikagelu (TLC).

The TLC method of the detection of T-2 toxin in grains is described. A thin layer of silica gel with a sensitivity of 3 mg/kg is used in this method. In comparison with the biological assay for dermal irritability, the TLC method is 30 times less sensitive. However, it has one great advantage over the bioassay: its specificity. It is recommended for practice to use a screening method based on the test for the dermal irritability of rabbits. When the content of toxins is higher, the analytic method can be used for trying to identify the given mycotoxin of the trichothecene group. T-2 toxin was detected in none of the 33 samples of tested grains (14 samples of barley, 7 wheat, 5 rye, 5 oats, 2 samples of maize).

[Biological assay for trichothecenes in grain]. / Biologická testace trichothecenu v zrninách.

Three different extract preparation procedures were used to produce the extracts to be applied to the skin of rabbits. In this way one hundred samples of the grains (wheat - 35, barley - 31, maize - 10, rye - 10, oats - 14) originating from the South Moravian, West Slovakian and East Slovakian regions were tested. These samples were taken from the 1980 crop which grew under climatic conditions extremely suitable for the growth of fusaria and the production of mycotoxins. Out of one hundred tested samples only five (5%) had a toxic effect on the rabbit skin. Out of these five samples only three (3%) contained T-2 toxin at the amount of 1 mg . kg-1 (two barley samples) and 0.1 mg . kg-1 (one barley sample) when examined semiquantitatively. The dermal changes evoked by two other samples were caused by other mycotoxins of the trichothecene group because the phenomenon typical of T-2 toxin (stronger skin reaction after 48 hrs than after 24 hrs after application) was not observed. The described method is recommended for screening examination of the grains for the presence of trichothecene mycotoxins.

[Study of cheeses for the presence of sterigmatocystin]. / Vysetrování sýru na prítomnost sterigmatocystinu.

Sixty-six samples of hard cheeses (Edam Block, Edam Cake, Svetlan, Moravian Block, Emmenthal), taken from retail shops, were examined by the chromatographic method using thin silica-gel layer. Three samples were positive. It was demonstrated by semiquantitative examination that two samples of Edam Cake contained 7.5 and 17.5 micrograms of sterigmatocystine in kg and one sample of Moravian Block contained 7.5 micrograms/kg. The described method is very simple and is recommended to be used by food-control institutions for the practical examination of cheese for the presence of sterigmatocystine.