sodium-nitrite and sodium-metabisulfite

Clostridium difficile is an important enteric pathogen of humans and food animals. Recently it has been isolated from retail foods with prevalences up to 42%, prompting concern that contaminated foods may be one of the reasons for increased community-acquired C. difficile infection (CA-CDI). A number of studies have examined the prevalence of C. difficile in raw meats and fresh vegetables; however, fewer studies have examined the prevalence of C. difficile in ready-to-eat meat. The aim of this study was to investigate the in vitro susceptibility of 11 C. difficile isolates of food animal and retail food origins to food preservatives commonly used in ready-to-eat meats. The broth microdilution method was used to determine the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) for sodium nitrite, sodium nitrate and sodium metabisulphite against C. difficile. Checkerboard assays were used to investigate the combined effect of sodium nitrite and sodium nitrate, commonly used in combination in meats. Modal MIC values for sodium nitrite, sodium nitrate and sodium metabisulphite were 250 μg/ml, >4000 μg/ml and 1000 μg/ml, respectively. No bactericidal activity was observed for all three food preservatives. The checkerboard assays showed indifferent interaction between sodium nitrite and sodium nitrate. This study demonstrated that C. difficile can survive in the presence of food preservatives at concentrations higher than the current maximum permitted levels allowed in ready-to-eat meats. The possibility of retail ready-to-eat meats contaminated with C. difficile acting as a source of CDI needs to be investigated.

Topics: Animals; Cattle; Clostridioides difficile; Food Microbiology; Food Preservatives; Meat; Microbial Sensitivity Tests; Nitrates; Sodium Nitrite; Sulfites; Swine

Identification of food chemical intolerance in asthmatic subjects can be reliably assessed by changes in the forced expiratory volume in one second (FEV1) in response to double blind, placebo controlled challenges on a strict elimination diet. However, this method is cumbersome and time consuming. A study was undertaken to determine whether changes in bronchial responsiveness to histamine following food chemical challenge without an elimination diet might be a faster, more convenient method.. Eleven adult asthmatic subjects were challenged twice with metabisulphite, aspirin, monosodium glutamate, artificial food colours, sodium nitrite/ nitrate, 0.5% citric acid solution (placebo), and sucrose (placebo) on separate days. During the first set of challenges subjects consumed a normal diet. Bronchial responsiveness to histamine was assessed 90 minutes after each challenge. A greater than twofold increase in bronchial responsiveness was considered positive. For one month prior to and during the second set of challenges subjects followed a strict elimination diet and FEV1 was monitored during and for two hours after each challenge. A fall in FEV1 of 20% or more was considered positive.. Of the 77 food chemical challenges performed on an unmodified diet, 20 were positive (six placebo responses). In two subjects it was not possible to perform a histamine test after one of the chemical challenges because of poor spirometric function. Of the 77 food chemical challenges performed on an elimination diet, 11 were positive (no placebo responses). Excluding the two challenges in which there were no corresponding histamine tests, only on two occasions did the positive responses in both methods coincide, giving the unmodified diet method a sensitivity of 22%.. Strict dietary elimination and measurement of FEV1 after double blind food chemical challenge remains the most reliable method for the detection of food chemical intolerance in asthmatic subjects.

Topics: Administration, Oral; Adult; Asthma; Bronchi; Cross-Over Studies; Diet; Double-Blind Method; Female; Food Coloring Agents; Food Hypersensitivity; Forced Expiratory Volume; Histamine; Humans; Male; Middle Aged; Sodium Glutamate; Sodium Nitrite; Sulfites

It was shown in experiments on 186 mice that formation of tumors of the lung and fore-stomach induced by injection of sodium nitrite in combination with aminopyrine or methylurea is inhibited following treatment with ascorbic acid, hexamethylenetetramine or sodium metabisulfite.

Topics: Aminopyrine; Animals; Ascorbic Acid; Cocarcinogenesis; Female; Lung Neoplasms; Male; Methenamine; Methylurea Compounds; Mice; Mice, Inbred Strains; Nitrites; Sodium Nitrite; Stomach Neoplasms; Sulfites

The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulfur dioxide offers a new option for the control of botulinal outgrowth in cured or noncured meat and poultry products.

Topics: Animals; Botulism; Clostridium botulinum; Food Microbiology; Food Preservation; Meat; Mice; Sodium; Sodium Nitrite; Sulfites; Sulfur Dioxide; Swine