Ppm Nitrite Research Articles

EFFECTS OF VARIOUS CONCENTRATIONS OF SODIUM NITRITE AND POTASSIUM SORBATE ON Clostridium botulinum TOXIN PRODUCTION IN COMMERCIALLY PREPARED BACON

ABSTRACTThe study consisted of five treatments including formulations with or without sodium nitrite (120 ppm) or potassium sorbate (0.26%) or both nitrite (40, 80 ppm) and sorbate (0.26%). Packages (300 per treatment) of commercially prepared bacon were inoculated with Clostridium botulinum spores from 10 strains (5 type A and 5 type B) and temperature abused at 27°C. Uninoculated packages (100 per treatment) were also abused. The packages were visually checked for gas production during a 60‐day incubation period and tested for botulinal toxin. Spore and vegetative cell counts, aerobic total plate counts, product pH, residual nitrite depletion, and sorbate levels were also monitored. Toxic samples frequently occurred without gas, and many samples showing gas were nontoxic. Added sorbate or added nitrite extended the time to detection of first gas‐containing and first toxic samples. A combination of sorbate (0.26%) with reduced nitrite levels (40, 80 ppm) extended this time further. Nitrite or sorbate used singly in the formulation also decreased the rate of toxin production. None of the uninoculated packages was toxic, while the total number of toxic inoculated packages decreased with nitrite or sorbate in the formulations. Ninety percent of the samples from the control treatment became toxic during the 60‐day incubation period; 58.8% from the treatment with 0.26% sorbate; 22.0% from the treatment with 40 ppm nitrite and 0.26% sorbate; none from the treatment with 80 ppm nitrite and 0.26% sorbate; and 0.4% from the treatment with 120 ppm nitrite. Low nitrite‐sorbate combinations were thus effective in delaying botulinal toxin production in temperature abused bacon.

EFFECTS OF VARIOUS CONCENTRATIONS OF SODIUM NITRITE AND POTASSIUM SORBATE ON NITROSAMINE FORMATION IN COMMERCIALLY PREPARED BACON

ABSTRACTPork bellies (270) were processed under regular commercial conditions using various concentrations (five treatments) of sodium nitrite and potassium sorbate. The bacon produced was stored at 3°C, then fried and tested for nitrosamines by GC‐TEA (Thermal Energy Analyzer) at 0 and 21 days after slicing. Nitrite and sorbate concentrations were determined weekly during a 49‐day period of 3°C storage. Bacon processed without sodium nitrite, regardless of sorbate concentration, contained low (<4.4 ppb) levels of N‐nitroso‐pyrrolidine (NPYR) after being fried at 171°C for 3 min on each side. Bacon processed with 40 ppm nitrite and 0.26% potassium sorbate contained an average of 8.7 ppb NPYR at zero time (after slicing) and 5.4 ppb after 21 days of 3°C storage under vacuum packaged conditions. Bacon with 80 ppm nitrite and 0.26% potassium sorbate had average NPYR levels of 14.3 ppb at zero time and 11.4 ppb after 21 days of refrigerated storage. Bacon made with 120 ppm nitrite contained an average of 28.1 ppb NYPR at zero time and 16.2 ppb after 21 days at 3°C. After frying the bacon, 61‐71% of the potassium sorbate remained in the product. Methods for nitrosamine analysis (CC‐TEA) and sorbate determination are described.

Effect of nitrate and nitrite in drinking water on rats

2-month-old male rats were given drinking water that contained either none, 4000 ppm sodium nitrate or 2000 ppm sodium nitrite for 14 months. During the treatment period the methemoglobin level of animals receiving nitrite fluctuated from 1–35% as compared with 0–2% for the groups receiving nitrate or water only. The red cell hemolysis was less than 5% in all 3 groups of animals. Relative to the control group, animals receiving nitrite had significantly lower body and liver weights and plasma vitamin E levels, higher red cell reduced glutathione (GSH) levels and higher incidence of pulmonary lesions, but nitrite had no effect on other parameters measured. Nitrate had a moderate effect on plasma vitamin E level and the incidence of pulmonary lesions. Ames' Salmorcella/microsome test showed an absence of mutagens in the feces extract of any of the animal groups. In another experiment, one-month-old male rats were given drinking water that contained either none, 200 ppm nitrite or 400 ppm nitrate for 16 weeks. The methemoglobin (MHb) level of the nitrite-treated animals ranged from 0.5–3.1% as compared with 0–1.2% of the other two groups. Except for higher incidence of pulmonary lesions, administration of nitrite or nitrate at these levels had no significant effect on any of the biochemical parameters measured in the blood or the mutagenicity of liver extract.

CONSUMER ACCEPTABILITY OF TURKEY FRANKFURTERS WITH 0, 40, AND 100 PPM NITRITE

ABSTRACTTurkey frankfurters formulated with 0, 40, and 100 ppm nitrite were evaluated for color, flavor, and overall acceptability by a consumer panel and for rancid and cured meat flavor and aroma by a trained panel. In addition, consumer preference was evaluated by determining the number of frankfurters that consumers selected to eat from each of the three formulations. Panelists selected more frankfurters with 40 or 100 ppm nitrite than they did frankfurters with 0 ppm nitrite. In our paired comparison of frankfurters with 0 vs 100 ppm nitrite, more consumers preferred the color of those containing 100 ppm nitrite. Their preference did not differ for 40 vs 100 ppm frankfurters. Trained panelists found no significant difference in flavor and aroma of frankfurters containing 40 vs 100 ppm nitrite, but flavor and aroma of frankfurters containing no nitrite were significantly different from those of frankfurters containing nitrite. Rancid aroma and flavor decreased and cured meat aroma and flavor increased with increasing nitrite concentration. Redness (a+ values) increased with increasing nitrite concentration. Samples containing no nitrite were significantly more yellow (b+ values) than those containing nitrite.

EFFECT OF NITRITE AND ERYTHORBATE ON RECOVERY OF Clostridium perfringens SPORES IN CURED PORK

ABSTRACTFresh pork shoulders were boned and ground through a 12.7 mm plate, packed in 1‐kg packages, frozen at −28.9°C and stored at −17.8°C for 2 wk. The frozen pork samples were thawed for 24 hr at 3°C, then blended with a curing mixture consisting of 6 parts of NaCl and 1 part sugar at a rate of 47.5g/kg of meat with erythorbate and NaNO2 added to give levels of 0,183, 366 or 550 ppm of erythorbate and 0, 50,100, 150 or 200 ppm nitrite in the meat. The pork was then inoculated at the rate of 11 spores of Clostridium perfringens (UK92)/g, packed in quart jars (500/g jar) and cured for 2 wk at 1‐4°C followed by 2 wk salt equalization at 12.8°C. Enumeration for C. perfringens began at this time and continued on alternate weeks during the 6‐wk aging period. Recovery of C. perfringens spores was significantly reduced by NaNO2. After 4 wk, 80% of the inoculated spores were recovered from samples with no added nitrite while only about one‐third of the spores were recovered from samples with the lowest level of NaNO2. Higher levels of nitrite and increased aging time reduced the number of spores recovered. At 10 wk, recovery was 38.0, 12.0, 5.4, 3.6 and 0.9% of inoculated spores, respectively, for 0, 50, 100, 150 and 200 ppm NaNO2. Sodium erythorbate had no significant effect on recovery of spores. Nitrite levels in the meat decreased rapidly with less than 60% of initial levels remaining after 24 hr. Only about 10% of initial concentrations were present after 4 wk. Results generally were similar for survival of C. perfringens spores and for nitrite losses when ground pork samples were dry‐cured in stockinettes and aged for the same time and at the same temperature as those cured in jars.

On the aetiology of gastric cancer: Mutagenicity of food extracts after incubation with nitrite

Treatment of certain foods, such as fish, beans and borscht which are typical of areas with a high incidence of gastric cancer, with 5000 ppm nitrite resulted in the formation of one or more mutagenic principles, as indicated by a Salmonella typhimurium test. S. typhimurium strain TA 1535 was the most sensitive of several indicator organisms tested. Formation of mutagenic material was highest at pH 3 with 5000 ppm nitrite, but significant amounts were also produced with 1000 ppm nitrite. More acidic as well as alkaline media led to a loss of the mutagenic activity over a 24-hr period. Ascorbic acid prevented the formation of the mutagenic material in nitrite-treated fish. Nitrite treatment of hot dogs, pork, beef, barley and sour milk produced no detectable mutagenic material.

Wiltshire curing with and without nitrate

SummaryThe storage life of vacuum packed unsmoked bacons produced by a factory Wiltshire process from brines containing nitrite with and without nitrate has been studied at 5° and 15°C. Whilst collar bacon produced from typical bacon pigs and containing 76–129 ppm nitrite and approximately 5% salt kept slightly better when it also contained 538–568 nitrate, no consistent benefit was noted when the nitrate concentration was 196–204. Collar and back bacons with similar concentrations of nitrite and salt and produced from pigs in which the ultimate pH in the M. longissimus dorsi was ≥ 6.0 kept better when they also contained approximately 600 ppm nitrate. It is suggested that the benefit of nitrate in these bacons is due to the inhibition of bacterial growth by increased concentrations of nitrite produced from nitrate in relatively high pH muscles.

Filter Paper as a Source of Error in the Determination of Nitrite in Meat

Samples of filter paper were found which contain sufficient nitrite to cause significant error in determining the nitrite content of cured meat products by the official AOAC method. Six of 28 boxes of filter paper examined were contaminated with nitrite. All 6 contaminated boxes were the same brand and grade. These samples of filter paper could contribute from 4.6 to 18.4 ppm nitrite to the amount of nitrite analyzed for in meat.

Wiltshire curing with and without nitrate

SummaryUnsmoked bacon has been made by a factory Wiltshire process incorporating hand pumping and immersion using brines with and without nitrate and with diminishing concentrations of nitrite. The quality and stability of the bacon during storage in vacuum packs has been compared.Curing with a nitrate‐free brine containing 26% salt and 1000 ppm nitrite produced back bacon with 57–81 ppm nitrite and approximately 4% salt in the lean and this, when sliced and vacuum packed, was still acceptable after 5 weeks at 5°C and 2 weeks at 15°C. Brines with nitrite concentrations of 500 ppm and less gave back bacon which was more prone to souring during storage due to increased growth of lactic acid bacteria.

EFFECT OF NITRITE AND STORAGE TEMPERATURE ON THE ORGANOLEPTIC QUALITY AND TOXINOGENESIS BY Clostridium botulinum IN VACUUM‐PACKAGED SIDE BACON

The effect of nitrite and storage temperature and toxinogenesis by Clostridium botulinum in vacuum‐packed side bacon was investigated. In two series of experiments (A & B) bacon packs were prepared with levels of 0, 50, 100, 150 and 200 ppm nitrite and inoculated with C botulinum at 102 spores/g and 104 spores/g. Packs A were incubated at 20 and 30° C and packs B at 30°C only. Both were held for a maximum of 32 days and analyzed for toxin at intervals of 2, 4, 8, 16 and 32 days. At 20°C none of the controls without nitrite was found to be toxic after 32 days. At 30°C inhibition of toxin formation at the higher nitrite levels was observed at 32 days. Organoleptic evaluation of the bacon packs stored at 30° C showed about one‐third of the toxic samples examined were acceptable to the panel.

The effect of pH on dimethylnitrosamine formation in human gastric juice

In view of the possibility of additional reaction mechanisms involving nitrosyl chloride and thiocyanate ion in the nitrosation of dimethylamine in human gastric juice and the limited amount of data concerning nitrosamine formation in gastric juice, the formation of dimethylnitrosamine (DMNA) from 100 ppm nitrite and 100 ppm dimethylamine was studied in a 50% aqueous solution of human gastric juice over a pH range of 1·7−4·5. Steam distillation and extraction with methylene chloride enabled an 80% recovery at the 25 ppb (b = 10 9) level, with verification by high resolution mass spectrometry. DMNA was formed over the entire pH range tested in amounts ranging from 9 to 34 ppb. From the data presented here it appears that the optimum pH for the nitrosation of dimethylamine in human gastric juice is in the region of 2·5 rather than 3·4, which was previously found to be the optimum pH in aqueous solutions free of HCl.

タラコ中のNO<sub>2</sub>定量法の検討

Some quantitative methods for nitrite in fish roe have already been published. In the present study, the characteristic factors of each method were examined twice by the table of orthogonal arrays of the 24 type with 16 replicates. From the experimental results, the authors present the following procedure: Extract 5 grams of the ground roe in a beaker of 100ml volume with 40ml of distilled water at 80°C for 30 minutes. After cooling to room temperature, add 5ml of saturated HgCl2 solution to the mixture. Remove it into a measuring flask of 100ml. Add distilled water to make the volume 100ml. Filter the mixture. Develop the color of the aliquot filtrate with a sulfamine reagent for nitrite determination. Measure the absorbance at 540mμ. The nitrite content of pollack roe sometimes decreases even after one day at 0°C. The recovery was 85.4% when 5 ppm of nitrite was added to the fish roe. From 6 repetitions of the determination, the coefficient of variation obtained was 3.44%.