Nitrite In Meat Research Articles

Collaborative Study of Modified AOAC Method of Analysis for Nitrite in Meat and Meat Products

A modified version of the AOAC method of analysis for nitrite in meat and meat products was tested collaboratively by 23 laboratories. Results were compared with those obtained by the official AOAC method. Recommended modifications include: (a) substitution of N-(1-naphthyl) ethylenediamine and sulfanilamide for Griess reagent, (b) separate addition and 1:10 dilution of the above reagents, (c) 20 min color development and absorbance read at 540 nm, (d) substitutionstitution of NaNO2 for AgNO2 and NaCL, (e) omission of mercuric chloride, (f) screening of filter paper for nitrite contamination, (g) more precise dilution of sample aliquot, and (h) standard curve linear up to 10 microng N/50 ml. Results were statistically treated by Youden's technique for comparing 2 methods, using a matched pair sample scheme. The random error for the modified method was significantly lower than the random error for the official method. A t-test showed no difference in bias between the 2 methods.

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.

Nitrite in meat. Effect of various compounds on loss of nitrite

Nitrite in meat. Effect of various compounds on loss of nitrite

Critical Evaluation of the AOAC Method of Analysis for Nitrite in Meat

Abstract Results of studies on the effects of 5 alternative procedures of sample preparation are presented. The standard deviations for the methods were 0.00505, 0.00142, 0.00307, 0.00265, and 0.00243, with the AOAC method giving the highest values for nitrite. The effects of some variables on the determination of the nitrite content of meat by the official method were also studied. These variables include the addition of mercuric chloride, duration of heating, rate of color reaction, and reagent preparation. The nitrite concentration as measured by the AOAC method varied with the initial dilution of meat sample. A number of compounds were added to the Griess reagent and nitrite solution to see whether they would affect the reaction. Reductants were found to interfere consistently. Suggestions for simplifying and improving the official method are made. These include omitting mercuric chloride, recrystallizing 1-naphthylamine before using, and allowing only 25 min for the completion of the color reaction, using a higher concentration of Griess reagent.

The Depletion of Added Sodium Nitrite in Ham

AbstractThe concentration of added sodium nitrite in meat is progressively lowered during curing, cooking, and storage. The rate of this depletion appears to be exponentially related both to pH and temperature. For ham meat the rate doubles for approximately every 22°F (12°C) increase in temperature or for every 0.86 pH units decrease over the range studied. Thus the “half life”, i.e. the time required for the nitrite to be depleted to ½ of its original value (with pH kept constant at 6.2), ranged from 513 hours at 40°F (4.4°C to only 1.6 hours at 220°F (104.4°C) and fiom 4.9 hours at pH 5.6 to 12 hours at pH 6.7 when temperature was held constant at 170°F (76.7°C). This relationship appears to be independent of initial nitrite concentration over the range of conditions tested and can be expressed mathematically by the equation “log10 (½ life) = 0.65 – 0.025 (Temperature °C) + 0.35 (pH). This relationship did not apply at room temperature. In this case the rate of nitrite depletion was unexpectedly rapid unless the product was first sterilized, indicating that bacterial consumption was probably a factor.

Collaborative Studies on Methods for Nitrate and Nitrite in Meat

Abstract Results of collaborative studies on three nitrate and two nitrite methods were examined by statistical procedures of Youden. The FeCl2 procedure was again found lo be subject to extreme bias. A modified procedure employing m-xylenol gave results which were somewhat improved in precision over previous tests. However, the procedure was still subject to systematic errors and rather large random errors resulting in only fair precision. A direct nitrate method based on color development with brucine was highly variable and unsatisfactory. The colorimetric procedure for nitrite, using Griess reagent, appeared to be relatively free of bias, but had only fair precision, and its usefulness is limited by the high standard deviation. An iodometric procedure, based on liberation of iodine from KI solution by the nitrite and titration with thiosulfate, proved to be quite precise and subject only to small bias, within acceptable limits of procedure. This method was far superior to the colorimetric method and should be adopted as official, first action for dry cure mix and pickle mix.

The Determination of Nitrate and Nitrite in Meat and Meat Products

The Determination of Nitrate and Nitrite in Meat and Meat Products