Die Nahrung最新文献

The organophosphorus insecticide naled (O,O-dimethyl-O,O-(1,2-dibromo-2,2-dichloroethyl)-phosphate, labeled by 32P] is degraded in milk in vitro at 5 degrees C with a half-life of 35 h with dichlorvos as a metabolite, that is also formed at short time heating and UV-irradiation. The recovery in milk powder is 25% (naled + dichlorvos) of the initial concentration. Following spray application of 0,05 mg naled/kg body mass to 2 lactating cows, 5-8 ppb of naled and 7-9 ppb of dichlorvos were found in the milk 5 h p.a., not exceeding the given tolerance level of 0,02 mg/kg in the German Democratic Republic.

Four independent studies were conducted in the course of two years to determine the retentions (or the losses) of vitamin A, beta-carotene, vitamin B1, vitamin B6, nicotinic acid and pantothenic acid during the ultra-high temperature sterilization of pre-pasteurized milk (85 degrees C without hold-up time) by means of the Alfa-Laval-Vtis-C apparatus (140 degrees C, 3-4 s, direct heating with subsequent expansion). The following retentions (or losses) were stated: vitamin A, 97.2% (2.8%); beta-carotene, 93.9% (6.1%); vitamin B1, 82.2% (12.0%); vitamin B2, 97.6% (2.4%); vitamin B6, 92.7% (7.3%) nicotinic acid, 96.0% (4.0%); and pantothenic acid, 96.4% (3.6%).

Different pretreatments were tried to recover Escherichia coli from food system and bacteriological diluents following freezing and thawing. The sublethally injured cells were found to repair their injury and start growing by resuscitating for 1 h in a non-nutrient medium at 37 degrees C. Longer periods did not give any improvement. Five media were studied for their recovery. Amongst the complex media, Eosine methylene blue agar was found to give maximum recovery. The organisms grew well on minimal medium also. Addition of vitamins and amino acids in the minimal medium did not show any increase in recovery. The results indicate that to detect index organisms such as E. coli from frozen systems, resuscitation in a non nutrient environment for at least 1 h necessary.

The cadmium contents of commercial foods and of meal samples from a factory canteen were examined over a period of 2 years and of 4 months, respectively. Furthermore, the cadmium contents of human organ samples obtained at necropsy were determined. The samples were subjected to wet digestion and analyzed by atomic absorption spectrophotometry. The value found for the cadmium intake by foods did not differ from international data. On the basis of the average cadmium values from the present investigation and of the per capitum consumption of the GDR population, the authors calculated a weekly cadmium intake from the major foods that amounts to approximately 50% of the WHO/FAO value. The cadmium contents of the human organ samples obtained at necropsy were somewhat lower than those from comparable foreign studies.

Contamination with ochratoxin A mainly and also with citrinin, penicillic acid and sterigmatocystin was observed in moldy cereal grain samples (wheat, rye, and barley), during 1975-1978 years. The levels of cereal grain contamination in various years were very different. However usually during two months after harvest percentage of contaminated samples was 5-7% and ochratoxin A content not higher than 140 microgram/kg. During storage of grain with high moisture content slow increase of contamination level was observed-particularly during January and February - to level 1-3 mg/kg. Cereal grain from commercial channels was contaminated with fungi spores sometimes up to 10(9) spores per gram. Aspergillus and Penicillium were predominating species. Between 69 fungi isolates typical for barley kernels 13 were procedures of ochratoxin, sterigmatocystin, penicillic acid and F-2 toxin. Results for wheat and rye will be published later.

In a feeding experiment with poultry a more than twofold cumulation of hexachlorobenzene (HCB) in eggs and in meat and a 7.5-fold cumulation in fat, in comparison with the concentration in the feed, have been demonstrated. With the aid of a combined identification by gas chromatography (before and after a conversion into anisole derivatives) and by thin layer chromatography the presence of pentachlorophenol in the liver, in fat and in muscles after feeding the birds with HCB as well as BHC-isomers has been proved. 2,4,6-trichlorophenol and 2,4-dichlorophenol were found by thin layer chromtography (without derivatisation). While 2,4,6-trichlorophenol was found after feeding with HCB only, 1,2,4,5-tetrachlorobenzene has been demonstrated by gas chromatography after feeding with HCB as well as with BHC-isomers.

The authors investigated the nitrogen content of different fractions and in particular the aminoacid composition of the trichloroacetic acid (TCA)-precipitable and TCA-soluble peptides in the distal small intestine of rats which had been fed experimental diets (nitrogen-free or containing casein, wheat gluten or molasses yeast as a protein carrier). Parallel with this, they determined in growing rats the nitrogen and amino-acid digestibility of molasses yeast and wheat gluten according to the technique of faecal analysis, and studied the amino-acid composition of the faecal protein. Independently of the dietary protein fed, the peptide fractions of the content of the intestine showed an amino-acid composition that was largely similar to that found in case of nitrogen-free diet. The amino-acid composition of the faecal protein is, independently of the dietary protein given, relatively constant and corresponds approximately to the intestinal loss protein. There is agreement between the amino-acid composition of the TCA-precipitable peptide fractions and those of the corresponding faecal proteins. These components seem to be of endogenous origin.

Using pancreatic lipase of Geotrichum candidum, the authors determined the fatty acid pattern and the glyceride structure of peanut, filbert, walnut, Brazil nut and cashew-nut fats. Both the fatty acid pattern and the glyceride structure were comparable to those of other vegetable fats of corresponding total fatty acid composition.