Determination of nitrite and nitrate levels in meat and vegetable products by high performance liquid chromatography

A range of fresh and processed meat and vegetable products was analysed by h.p.l.c. for nitrite and nitrate contents. Satisfactory results were obtained for vegetable products and most meats, but some meat products were subject to matrix interference. Sucrose, sulphate and phosphate did not affect results. Added sodium chloride decreased retention time of nitrite and increased apparent levels of both nitrite and nitrate. Ascorbic and erythorbic acids decreased apparent nitrite levels and correspondingly increased apparent nitrate levels.     

Survey of naturally and conventionally cured commercial frankfurters,ham, and bacon for physio-chemical characteristics that affect bacterial growth

Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.     

Additives in finnish sausges and other meat products

Additives such as sodium nitrate, potassium nitrate, sodium nitrite, phosphates and sodium chloride in sausages and various meat products were examined. Nitrate, nitrite and phosphate concentrations were below the maximum permitted levels, but most of the samples examined contained large amounts of sodium chloride and were thus "extra salted". Sausage factories should lower the salt concentrations in their products.     

Nitrate and nitrite quantification from cured meat and vegetables and their estimated dietary intake in Australians

High dietary nitrate and nitrite intake may increase the risk of gastro-intestinal cancers due to the in vivo formation of carcinogenic chemicals known as N-nitroso compounds. Water and leafy vegetables are natural sources of dietary nitrate, whereas cured meats are the major sources of dietary nitrite. This paper describes a simple and fast analytical method for determining nitrate and nitrite contents in vegetables and meat, using reversed-phase HPLC-UV. The linearity R² value was >0.998 for the anions. The limits of quantification for nitrite and nitrate were 5.0 and 2.5 mg/kg, respectively. This method is applicable for both leafy vegetable and meat samples. A range of vegetables was tested, which contained <23 mg/kg nitrite, but as much as 5000 mg/kg of nitrate. In cured and fresh meat samples, nitrate content ranged from 3.7 to 139.5 mg/kg, and nitrite content ranged from 3.7 to 86.7 mg/kg. These were below the regulatory limits set by food standards Australia and New Zealand (FSANZ). Based on the average consumption of these vegetables and cured meat in Australia, the estimated dietary intake for nitrate and nitrite for Australians were 267 and 5.3 mg/adult/day, respectively.     

盐类及超高压对猪脂肪氧化稳定性的影响

脂肪氧化是导致肉制品品质劣化的重要原因。以猪背脂肪为原料,在90℃、高氧条件下研究氯化钠、氯化钾、硝酸钠、亚硝酸钠、异抗坏血酸钠和三聚磷酸钠6种肉制品加工常用添加剂以及常温下超高压处理对其氧化诱导期的影响。结果表明:添加盐类会导致猪背脂肪的氧化稳定性下降,氧化诱导期缩短,影响作用依次为异抗坏血酸钠亚硝酸钠氯化钾三聚磷酸钠氯化钠硝酸钠;超高压处理会降低猪背脂肪氧化稳定性,其作用随压力增大而增大。     

Antibacterial activity of Capsicum extract against Salmonella typhimurium and Pseudomonas aeruginosa inoculated in raw beef meat

The inhibitory effect of the extract of Capsicum annuum bell pepper type was evaluated against Salmonella typhimurium and Pseudomonas aeruginosa, inoculated in minced beef meat mixed with different concentrations of the extract, and stored at 7 degrees C for 7 days. The combined effect of C. annuum extract and sodium chloride on the bacterial growth was evaluated. The minimum inhibitory concentration of the extract to prevent the growth of S. typhimurium in minced beef was 1.5 ml/100 g of meat; the addition of 1%, 2%, 3% and 4% w/w of sodium chloride did not have any additional inhibitory effect on Salmonella. In the case of P. aeruginosa, a concentration of 0.3 ml of the extract/100 g of meat showed a bacteriostatic effect, while a concentration of 3 ml/100 g of meat showed a bactericidal effect. When 1% w/w of sodium chloride was added to the meat together with the extract, the concentration needed to kill P. aeruginosa was reduced.     

Headspace concentration of selected dry-cured aroma compounds in model systems as affected by curing agents

The effect of curing agents (sodium chloride, nitrate, nitrite, glucose, and ascorbic acid) on the headspace concentration of six volatile compounds (2-methyl-butanal, 3-methyl-butanal, 2-pentanone, hexanal, methional, and octanal) has been studied. These volatile compounds were selected based on their presence and contribution to the flavour of typical Spanish dry-cured meat products. The release of volatile compounds to the headspace has been studied by using solid-phase microextraction (SPME) and gas chromatography analysis. The main effect was produced by sodium chloride, because it produced a salting-out effect on all the volatile compounds studied. Furthermore, the presence of nitrite, nitrate, and ascorbic acid in the solution also produced an increase in the headspace concentration of the volatile compounds while glucose decreased the headspace concentration of octanal and hexanal. The changes in the relative proportions of volatile compounds due to the effect of curing agents should be taken into account as they may change the flavour perception of dry-cured meat products.     

Inactivation of Yersinia enterocolitica by nitrite and nitrate in food.

The antimicrobial effects of sodium nitrite and sodium and potassium nitrate against Yersinia enterocolitica were investigated in solution and in treated pork meat. Potassium nitrate and sodium nitrate showed only feeble antimicrobial activity in cultures; no antimicrobial activity was detected with sodium nitrite. Conversely, all three salts displayed apparent antimicrobial activity in pork meat, possibly due to selective effects on competitive flora.     

Minimum sodium nitrite levels for pinking of various cooked meats as related to use of direct or indirect-dried soy isolates in poultry rolls

The relationship between sodium nitrite level and pinking was investigated in cooked meats, as measured by panel color score, acetone extraction of NO-hemochrome, and instrumental redness values. Beef was less susceptible than poultry breast meat to nitrite-induced pinking. Minimum sodium nitrite level for pinking was 14, 4, 2, and 1 ppm for beef round, pork shoulder, turkey breast, and chicken breast, respectively. By regression analysis, minimum ppm nitrite for pinking=0.092 (ppm total pigment)+0.53 (R(2)=0.99). High levels of nitrate (>250 ppm as sodium nitrate) and nitrite (>45 ppm as sodium nitrite) were found in direct-dried (DD) soy isolates. Chicken breast rolls formulated with >2% DD soy were pink, but control rolls with 156 ppm sodium nitrate were not pink. Thus, it was concluded that nitrite was the primary pinking agent in DD soy. Indirect-dried (ID) soy isolates contained <11 ppm sodium nitrite, which was insufficient for pinking in poultry rolls.     

The effect of chloride salts onYersinia enterocoliticain meat

The populations ofYersinia enterocolitica(serotypes 0:3 and 0:8) exposed to NaCl, KCl and CaCl₂in meat, decreased as the concentration of each salt increased. Calcium chloride was significantly (α=0.05) more effective against serotype 0:8. Sodium nitrite was synergistic to the anti-yersinial effect of NaCl. Mathematical equations were developed for the prediction of the population ofY.enterocoliticain meat, exposed to the chloride salts. In addition, these equations can also be used to determine the concentration of a chloride salt required for attaining a predetermined level of the pathogen. The Anti-yersinial Index (AI) demonstrated that CaCl₂was most efficient against serotype 0:3 while the higher concentrations of KCl (1.8 and 2.2% w/w Cl) were most efficient against serotype 0:8.     

The oxidative stability of lard at −20°C: Evidence for a synergistic prooxidant effect of copper and curing salts

In connection with an interest in the problem of rancidity development in cold-stored cured meat products (particularly bacon), the effect of certain trace components and permitted food additives on the oxidative stability of model systems containing lard was examined. Lard, to which additions of various single additives or combination of additives had been made, was stored for periods of up to 16 weeks at ?20°C. Samples were removed during this time to assess the extent of their oxidation by chemical analysis (peroxide value determination) and sensory evaluation (odour). The additives studied included water, sodium chloride, sodium nitrate, sodium nitrite and copper (as palmitate, acetate and sulphate). It was observed that there was progressive oxidative deterioration of the lard with noticeable rancidity developing after 8 to 16 weeks' storage at ?20°C when water, sodium chloride, sodium nitrate, sodium nitrite and copper were present in combination.     

肉糜加工中亚硝酸盐的变化及预测模型建立?

以肉糜为材料,研究腌制、常压蒸煮、高压蒸煮单元加工条件及NaNO2 添加量对肉糜中NaNO2 残留量的影响。考察建立NaNO2 添加量、腌制时间、煮制时间、蒸煮温度对NaNO2 残留量影响的预测模型,并对模型进行验证。结果表明：腌制阶段NaNO2 残留量与NaNO2 添加量呈显著正相关,与腌制时间呈显著负相关;蒸煮阶段NaNO2 残留量与NaNO2 添加量呈显著正相关,与蒸煮温度与时间呈负相关;动力学模型分析表明,高压蒸煮对NaNO2 残留量下降速率的影响比常压蒸煮大,不同温度对NaNO2 残留量的影响极其显著(P ＜ 0.01);80℃与121℃条件下建立的预测模型R2 分别为0.939、0.888。预测模型试验值与回归值符合得比较好,相对误差小于10%。     

Effect of reducing nitrate and nitrite added to dry fermented sausages on the survival of Salmonella Typhimurium

Salmonella is one of the pathogens that most frequently contaminate pork processing lines. Several hurdles can control this organism in dry fermented sausages, among them is nitrite. However, the traditional use of nitrate/nitrite in the meat industry is being questioned due to their involvement in nitrosamine formation. In this study, minced pork and sausages inoculated with Salmonella Typhimurium were prepared with 150 ppm NaNO₃ and 150 ppm NaNO₂ (maximum amounts allowed by EU), and with a reduction of 25% and 50%. The absence of nitrate/nitrite favored Salmonella growth, with 2–2.5 log cfu/g higher counts at the end of ripening, compared to nitrate/nitrite added batches. The 50% reduction showed the same inhibitory effect as the maximum amounts. Nitrate/nitrite represented an essential hurdle to control Salmonella even when pH and a_w were below the values considered as minimum for its growth. The effect of this reduction on other pathogens should be considered.     

Exposure estimates of nitrite and nitrate from consumption of cured meat products by the U.S. population

The dietary exposures of nitrite and nitrate from consumption of cured meat products were estimated for the U.S. population aged 2 years and older, and children aged 2 to 5 years, using both 2-day food consumption data from the publicly available combined 2009–2012 National Health and Nutrition Examination Survey (NHANES) and 10–14-day food consumption data from the 2009 and 2012 NPD Group, Inc. National Eating Trends-Nutrient Intake database (NPD NET-NID), and residual nitrite and nitrate levels in cured meat products available from the recent American Meat Institute Foundation/National Pork Board (AMIF/NPB) national market survey of the nitrite and nitrate levels in cured meat products in the U.S.A. The dietary exposure for consumers of cured meat products (eaters-only) was estimated at the mean and 90th percentile for three exposure scenarios: low exposure, average exposure, and high exposure, to account for the range in the amount of nitrite and nitrate in a given cured meat product category. In addition, a cumulative exposure that takes into account all cured meat product categories containing nitrite and nitrate was determined, and the relative percent contribution of each cured meat product category to the cumulative exposure was estimated. Cured, cooked sausages and whole-muscle brine-cured products were the two major contributing categories to dietary exposure of nitrite and nitrate for both U.S. population aged 2 years and older and children aged 2–5 years.     

Determination of nitrate,nitrite and perchlorate anions in meat,milk and their products consumed in Hatay region in Turkey

Nitrates and nitrites added to food can cause formation of cancerous N-nitroso compounds, whereas exposure to perchlorate is especially emphasised as an important risk factor for newborns’ health. In this study, nitrate, nitrite and perchlorate concentrations in meat and milk products consumed in the Hatay region of Turkey were determined. Nitrate and nitrite were analysed with a spectrophotometric method, and perchlorate analysed via ion chromatography. The detected sodium nitrate and nitrite amounts in meat consumed in the Hatay region are less than the maximum levels as declared in the Turkish Food Codex. The amount of perchlorate was considered not to pose a threat as well. However, in 50% of the cheese samples, sodium nitrate amounts were found to be more than the maximum acceptable level in the Turkish Food Codex.     

Survey of naturally and conventionally cured commercial frankfurters, ham, and bacon for physio-chemical characteristics that affect bacterial growth

Natural and organic food regulations preclude the use of sodium nitrite/nitrate and other antimicrobials for processed meat products. Consequently, processors have begun to use natural nitrate/nitrite sources, such as celery juice/powder, sea salt, and turbinado sugar, to manufacture natural and organic products with cured meat characteristics but without sodium nitrite. The objective of this study was to compare physio-chemical characteristics that affect Clostridium perfringens and Listeria monocytogenes growth in naturally cured and traditionally cured commercial frankfurters, hams, and bacon. Correlations of specific product characteristics to pathogen growth varied between products and pathogens, though water activity, salt concentration, and product composition (moisture, protein and fat) were common intrinsic factors correlated to pathogen growth across products. Other frequently correlated traits were related to curing reactions such as % cured pigment. Residual nitrite and nitrate were significantly correlated to C. perfringens growth but only for the ham products.     

Effects of curing additives on the control ofListeria monocytogenesby lactocin 705 in meat slurry

Meat slurry inoculated withListeria monocytogenes(4.00 cfu g⁻¹) was mixed with different levels of curing additives and their influence on the inhibitory effect of lactocin 705 (17,000 AU ml⁻¹) was evaluated at 20°C. Inhibition ofL. monocytogeneswas 1.90 and 1.00 log less in meat slurry with 5 and 7% NaCl than in meat slurry without added sodium chloride. When nitrite and bacteriocin were added together, less nitrite (200 μg g⁻¹) was required to obtain the sameListeriapopulation (3.00 log cfu g⁻¹) as when 800 μg g⁻¹NaNO₂was used. However, when compared with lactocin 705 alone, lessListeriainhibition was observed showing also a protective effect of NaNO₂. When ascorbic acid and alginate meat binder were assayed in the presence of the bacteriocin, the inhibition ofL. monocytogeneswas less effective, but when sodium lactate (2%) was added to the meat slurry, almost no protective effect was observed. These results indicated that the use of lactocin 705 to controlL. monocytogeneswas less effective in the presence of curing ingredients.     

Direct infusion of nitrite into meat batter by atmospheric pressure plasma treatment

This study investigated the influence of direct atmospheric pressure plasma (APP) treatment on nitrite levels and physiochemical quality of meat batter during the mixing process. A compact APP system was developed for installation on top of a food mixer. Meat batter composed of pork, water and sodium chloride (80:20:1, w/w/w) was treated with APP during mixing. Plasma treatment gradually increased the temperature of meat batter over 60 min from 0.2 °C to 20 °C. Total aerobic bacterial count of meat batter was not influenced by plasma treatment for 30 min (p > 0.05). The nitrite level in meat batter increased steadily with increasing plasma treatment duration (p < 0.05), reaching 65.96 ppm at 30 min. Consequently, the CIE a*- and b*-values of cooked meat batter gradually increased and decreased, respectively, as the time of plasma treatment increased. According to the results, direct APP treatment can replace nitrite addition in cured meat processing.     

Studies of levels of biogenic amines in meat samples in relation to the content of additives

The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.     

Effect of adding smoke-flavouring to frankfurters on nitrite and nitrate levels

Different concentrations of sodium nitrite, potassium nitrate or both together were used to prepare four standard solutions and four frankfurter formulations. These were elaborated with and without the addition of 2 g/kg of a commercial solid smoke-flavouring preparation. Monitoring of nitrite and nitrate residual levels in standard solutions stored at 3 °C showed that smoke-flavouring addition results in a depletion of nitrite levels and/or reduction of nitrate to nitrite. In a much more complex system such as meat products, nitrite and nitrate, incorporated in the formulation separately or combined, were also rapidly depleted when smoke-flavouring was added.