sodium-nitrite and potassium-nitrate

Toxic effects of nitrates and nitrites on absorptive and secretive functions of intestinal mucosa were described. The effect of nitrates and nitrites on maturation, differentiation and programmed cell death (apoptosis) in intestinal crypts was also discussed. Selected immunological functions of small intestine in nitrate- or nitrite-treated organism were evaluated.

Topics: Animals; Gastric Mucosa; Intestine, Small; Nitrates; Potassium Compounds; Rats; Sodium Nitrite

The viability of using microbial transglutaminase (MTGase) as a cold-set binder for restructuring and manufacturing deboned dry ham (RDH) was evaluated. The influence of meat pre-treatment, preparation of the MTGase, packing system and set temperature on the binding rate and force was tested using pork models and deboned legs. The best binding parameters were obtained when meat surfaces were evenly distributed with salts (NaCl, KNO(3), NaNO(2)) and then washed with a saline solution (W), afterwards powder (P) or liquid (L) MTGase was applied, and simultaneous salting and vacuum packing (S) set at 7 degrees C were performed. The RDH manufactured following these procedures (WPS and WLS) was stable during drying and could resist the handling and production process. Binding force increased (p<0.05) during 8 weeks of drying. Scanning electron microscopy analysis showed an increase of cross-links during the drying period of RDH related to the increase in binding force.

Topics: Animals; Food Handling; Food Preservation; Food Preservatives; Meat Products; Microscopy, Electron, Scanning; Nitrates; Potassium Compounds; Sodium Chloride; Sodium Nitrite; Swine; Temperament; Transglutaminases; Water

Topics: Animals; Apoptosis; Intestinal Mucosa; Intestine, Small; Male; Mice; Nitrates; Potassium Compounds; Sodium Nitrite

The spoilage flora of vacuum-packaged, salted, cold-smoked rainbow trout fillets, with or without the addition of nitrate or nitrite, stored at 4 degrees C and 8 degrees C, was studied. Of 620 isolates, lactic acid bacteria were the major fraction (76%), predominating in all samples of spoiled product. However, the phenotypical tests used were insufficient to identify the lactic acid bacteria to the species level. Gram-positive, catalase-positive cocci, gram-negative, oxidase-negative rods and gram-negative, oxidase-positive rods were found in 6%, 16% and 2% of the samples, respectively. Of 39 gram-positive, catalase-positive cocci, 29 were identified as staphylococci and 10 as micrococci. Eighty-five isolates were found to belong to the family Enterobacteriaceae, with 45 of those being Serratia plymuthica. Eleven isolates from the nitrate treated samples stored at 8 degrees C were identified as Pseudomonas aeruginosa. The occurrence of P. aeruginosa and staphylococci in the nitrate-containing samples, stored at 8 degrees C, may cause problems with respect to the safety of the product. The types of lactic acid and other bacteria in the spoilage flora were generally reduced by the addition of nitrate or nitrite to fillets.

Topics: Animals; Bacteria; Colony Count, Microbial; Fish Products; Food Microbiology; Food Packaging; Food Preservation; Humans; Nitrates; Oncorhynchus mykiss; Potassium Compounds; Refrigeration; Smell; Sodium Chloride; Sodium Nitrite; Taste

The effect of sodium-nitrite (NaNO2) and potassium nitrate (KNO3) on the outgrowth and toxigenesis of nonproteolytic Clostridium botulinum in vacuum-packed cold-smoked rainbow trout stored for-six weeks was studied in two inoculation studies at slightly abusive storage temperatures of 4 degrees C and 8 degrees C. The depletion rate of nitrite and the reduction rate of nitrate to nitrite as well as the effect of nitrite and nitrate on the shelf-life of the product during eight weeks' storage period were also determined. The nitrite concentrations were reduced from 166 mg/kg +/- 9 (mean +/- SE), to a final concentration of 34 mg/kg +/- 2 and 11 mg/kg +/- 2, and the nitrate concentrations from 686 mg/kg +/- 67 to 465 mg/kg +/- 140 and 427 mg/kg +/- 33 at 4 degrees C and 8 degrees C respectively. The nitrite depletion rate was more rapid at 8 degrees C; nitrate depletion was not significantly affected by temperature. A considerable amount of nitrite was detected in the nitrate-treated samples in the latter half of the storage period. At 4 degrees C the aerobic plate counts were significantly lower in the samples treated with NaNO2 + NaCl and with KNO3 + NaCl as compared to the NaCl-treated controls, while at 8 degrees C the differences were smaller. The sensorial shelf-life of the product was considerably extended by nitrite and nitrate curing. The nitrite and nitrate concentrations used in the present study did not completely inhibit the toxigenesis of nonproteolytic C. botulinum during the six-week storage period, although the number of toxic samples was considerably reduced by nitrite and nitrate curing.

Topics: Animals; Botulinum Toxins; Clostridium botulinum; Food Preservation; Nitrates; Oncorhynchus mykiss; Potassium Compounds; Sodium Chloride; Sodium Nitrite

Two nitrogen-regulated genes were found in the genomic DNA region upstream of the nirA operon involved in uptake and utilization of nitrate in Synechococcus sp. strain PCC7942. The two genes (nirB and ntcB) are transcribed divergently from nirA and encode proteins of 349 and 309 amino acid residues, respectively. The levels of nirB and ntcB transcripts were low in cells growing on ammonium and increased upon transfer of ammonium-grown cells to nitrate-containing medium. The deduced NirB protein sequence has no similarities to other known proteins, whereas the deduced NtcB protein sequence is homologous to bacterial transcriptional activators of the LysR family. Defined mutants constructed by interrupting nirB or ntcB with a drug resistance marker grew as fast as the wild-type strain on ammonium but grew slower than the wild-type strain on nitrate or nitrite. The nirB mutant had higher activities of nitrate reductase, glutamine synthetase, and glutamate synthase than the wild-type strain, but its nitrite reductase activity was 40% of the wild-type levels. The mutant excreted nitrite into the medium during growth on nitrate, showing that nitrite reductase limits nitrate assimilation. These findings suggested that nirB is required for expression of maximum nitrite reductase activity. When grown on ammonium, the nirB mutant grew normally but cultures of the ntcB mutant still showed a yellowish-green color typical of nitrogen-limited cells. NtcB seems to regulate utilization of fixed nitrogen by controlling the expression of a certain gene(s) involved in nitrogen metabolism.

Topics: Amino Acid Sequence; Ammonium Sulfate; Bacterial Proteins; Base Sequence; Cyanobacteria; Genes, Bacterial; Molecular Sequence Data; Mutagenesis, Insertional; Nitrates; Nitrogen; Phenotype; Potassium Compounds; Sodium Nitrite; Trans-Activators

The intestinal transport of D-xylose was studied during subchronic poisoning of male Wistar rats with the oral administration of potassium nitrate and sodium nitrite. The metabolic parameters of small intestine mucosa were determined one hour after xylose administration, i.e., Na+/K(+)-ATPase, alkaline phosphatase, oxygen consumption, and lactic acid level. Nitrite reduced the absorption of xylose and decreased the activity of Na+/K(+)-ATPase and alkaline phosphatase. No effect of sodium nitrite was demonstrated on the aerobic metabolism of intestinal mucosa with an increased lactic acid level. Potassium nitrate did not effect the processes of intestinal absorption of xylose nor the metabolic parameters of small intestine mucosa.

Topics: Administration, Oral; Alkaline Phosphatase; Animals; Gastric Mucosa; Intestinal Absorption; Intestinal Mucosa; Male; Nitrates; Oxygen Consumption; Potassium Compounds; Rats; Rats, Inbred Strains; Sodium Nitrite; Sodium-Potassium-Exchanging ATPase; Xylose

The intestinal transport of D-xylose was studied during the acute poisoning of male Wistar rats with orally administered potassium nitrate and sodium nitrite. At the peak of xylose absorption, the metabolic parameters of Na+/K(+)-ATPase, alkaline phosphatase, oxygen uptake, and lactic acid level were determined in the small intestine mucosa. Nitrite in a dose of 80 mg NaNO2/kg b.w. increased the permeability of gastric mucosa for D-xylose and raised the uptake of oxygen by the small intestine mucosa. No changes were observed in the activity of Na+/K(+)-ATPase and alkaline phosphatase. A dose of 10 mg NaNO2/kg b.w. was not followed by increased absorption of this sugar. It was also demonstrated that potassium nitrate had no effect on the process of intestinal absorption of D-xylose and failed to change the determined metabolic parameters of the small intestine mucosa.

Topics: Administration, Oral; Animals; Gastric Mucosa; Intestinal Absorption; Intestinal Mucosa; Male; Nitrates; Oxygen Consumption; Potassium Compounds; Rats; Rats, Inbred Strains; Sodium Nitrite; Sodium-Potassium-Exchanging ATPase; Xylose

The intestinal absorption of D-xylose was studied during acute poisoning of male Wistar rats receiving intragastrically potassium nitrate and sodium nitrite and small intestine perfusion with these compounds. The metabolic parameters, Na+/K(+)-ATPase, alkaline phosphatase, oxygen uptake, and lactic acid level, were assessed in the small intestine mucosa one hour after administration of these compounds. Exercise was demonstrated to reduce the intestinal absorption of D-xylose, to raise the level of lactic acid, and to increase the oxygen uptake by the small intestine mucosa, but caused no changes in the activity of Na+/K(+)-ATPase or alkaline phosphatase. Also, exercise failed to change the direction of the toxic effects of sodium nitrite but increased potassium nitrate toxicity as evidenced by reduced absorption of D-xylose from the intestine despite lack of changes of the enzymes Na+/K(+)-ATPase and alkaline phosphatase in the mucosa.

Topics: Alkaline Phosphatase; Animals; Dose-Response Relationship, Drug; Intestinal Absorption; Intestinal Mucosa; Male; Nitrates; Oxygen Consumption; Physical Conditioning, Animal; Potassium Compounds; Rats; Rats, Inbred Strains; Sodium Nitrite; Sodium-Potassium-Exchanging ATPase; Xylose

The intestinal absorption of D-xylose was studied during the subchronic poisoning of male Wistar rats with orally administered potassium nitrate and sodium nitrite associated with exercise; running on a moving track during the last two weeks of poisoning. The metabolic parameters of Na+/K(+)-ATPase, alkaline phosphatase, oxygen uptake, and lactic acid level in the small intestine mucosa were determined one hour after D-xylose treatment. Exercise increased the toxicity of potassium nitrate and sodium nitrite. The experiment demonstrated post-exercise reduction of D-xylose absorption and decrease activity of Na+/K(+)-ATPase and alkaline phosphatase. Exercise caused transient hypoxia of the small intestine, which was observed only in the groups subjected to exercise on the day of the determinations.

Topics: Administration, Oral; Alkaline Phosphatase; Animals; Intestinal Absorption; Intestinal Mucosa; Male; Nitrates; Oxygen Consumption; Physical Conditioning, Animal; Potassium Compounds; Rats; Rats, Inbred Strains; Sodium Nitrite; Sodium-Potassium-Exchanging ATPase; Xylose

In the region of Puławy where the operation of the Nitrogen-Compound Manufacturing Plant has lead to an increase in nitrogen compound emission to the environment, nitrate and nitrite contents in daily food rations of children were determined. Daily food rations of children aged 8-9 and 12-13 years were collected from individual farms in four villages situated in the vicinity of the Nitrogen Plant, as well as--for control--from individual farms in Janowiec, a village distant from this Plant. Nitrate and nitrite contents were assayed in 300 daily food rations taken in spring and autumn. Nitrate was reduced to nitrite on a cadmium column whereupon it was determined colorimetrically using sulphanilic acid and N-1-napthyl-ethylenediamine. It was found that in the group of younger children as many as 70%, on the average, of the examined food rations displayed nitrate contents exceeding the admissible levels. In the group of the 12-13 years old children, the percentage of daily food rations whose nitrate content exceeded the admissible level was lower, averaging ca. 30% of all rations examined. The percentage of the daily food rations in which the nitrite content was higher than admissible level was closely similar in both groups of children, averaging ca. 30% of all rations examined. Food rations collected in spring, as compared with those taken in autumn, contained significantly greater amount of nitrate. In both periods of studies, nitrate contents were greater in the food rations from the farms situated near the Nitrogen Plant than in the food rations from farms in Janowiec.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Chemical Industry; Child; Dietary Services; Environmental Pollutants; Food Contamination; Humans; Nitrates; Nitrogen; Poland; Potassium Compounds; Rural Population; School Health Services; Seasons; Sodium Nitrite

The limit levels of potassium nitrate and sodium nitrite were determined in the diet of rats receiving orally beta-carotene. Two 30-day biological experiments were done on male Wistar rats standardized for vitamin A level in the liver. The animals were given semisynthetic diet, without vitamin A, containing definite amounts of potassium nitrate or sodium nitrite: 4.0; 4.5; 5.0; 5.5; 6.0% of the nitrate, and 0.5; 0.6; 0.7; 0.8; 0.9; 1.0% of the nitrite. The rats were given also orally two drops of an oil solution of beta-carotene in doses of 30 micrograms per rat daily. The limit of tolerance was established measuring beta-carotene utilization according to the method of balance studies and liver function test. Diet consumption and body weight of the animals were considered as well. It was found that in this experiment the limit dose, that is the dose of nitrates and nitrites over which the rats died, was 5.0% for nitrate and 0.7% for nitrite.

Topics: Animal Feed; Animals; beta Carotene; Carotenoids; Dose-Response Relationship, Drug; Liver; Male; Maximum Allowable Concentration; Models, Biological; Nitrates; Potassium Compounds; Rats; Rats, Inbred Strains; Sodium Nitrite; Vitamin A

Topics: Animals; Ascorbic Acid; Campylobacter fetus; Cattle; Culture Media; Meat; Nitrates; Phosphates; Potassium Compounds; Sodium Chloride; Sodium Glutamate; Sodium Nitrite; Tissue Extracts

A stability-indicating analytical method is described for the simultaneous determination of nitrate, and if present, its reductive degradation product, nitrite, in toothpastes. Nitrate and nitrite were extracted from the toothpaste using distilled water and separated from other water-soluble excipients by two RP-8 columns (250 mm X 4 mm i.d.) using a mobile phase containing 0.2% (w/v) sodium acetate and 2.5% (v/v) glacial acetic acid in distilled water. A UV detector set at 313 nm was used for quantitation. The method was applied to commercial toothpastes containing 5% potassium nitrate and yielded an average recovery of 100.1% with a relative standard deviation of 1.43%. Average recovery of nitrate and nitrite from spiked samples were 100.6% and 96.4%, respectively. The minimum detectable concentration for nitrite was 50 micrograms/g of toothpaste.

Topics: Chromatography, High Pressure Liquid; Dentifrices; Nitrates; Nitrites; Potassium Compounds; Sodium Nitrite; Toothpastes