The relationship of added nitrate to pigment formation in native pork-sausage (longaniza)

The nitrosomyoglobin, residual nitrate and nitrite concentrations of the native pork-sausage (longaniza) were analysed within a ten-day storage period. Several levels of nitrate (50, 100, 300, 500 and 2000, 3500 and 5000 ppm) were employed. These were examined to determine the minimum amount of nitrate that could be added to the curing mixture for the making of longaniza whilst still obtaining acceptable organoleptic properties, especially colour.Pigment formation in longaniza due to the added nitrate occurs from the onset and reaches its maximum on the third or fourth day. The desirable pink to red colour in the cured meat was obtained even with amounts of nitrate as low as 50 ppm. All treated longaniza showed high and similar colour scores compared with the control. However, higher colour stability was obtained with the use of greater than 500 ppm nitrate. The amount of residual nitrate and nitrite is directly proportional to the initial quantity of nitrate added. The use of 50 to 500 ppm nitrate poses no danger to public health while the use of 2000 to 5000 ppm nitrate enhances the possibility of carcinogenic nitrosamine formation and incidence of methemoglobinemia.     

Effects of Particle Size, Casing Diameter, and Addition of Emulsions and Residual Nitrite on Quality Attributes of Cooked Salami

Cooked salami was manufactured from raw materials of two particle sizes (6.5 and 13.0 mm) with and without the addition of 25% meat batter, and stuffed into two sizes of casings (64 and 90 mm). A fourth variable, three levels of added nitrite (110, 220, and 440 ppm) was also included in the experimental design. Increasing the particle size and casing diameter resulted in less shrinkage and a firmer product. The use of 25% added meat batter reduced shrinkage but made a softer product upon heat processing than without meat batter added. Neither sensory nor textural properties were significantly influenced (p < 0.05) by the level of nitrite added. Levels of residual nitrite decreased upon storage of the product up to 14 days.     

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.     

Effects of curing sodium nitrite additive and natural meat fat on growth control of Listeria monocytogenes by the bacteriocin-producing Lactobacillus curvatus strain CWBI-B28

In realistic model meat systems, the separate and combined effects of fat content and sodium nitrite on the antilisterial activity of the bacteriocin of Lactobacillus curvatus CWBI-B28 were studied. In laboratory fermentations where Listeria monocytogenes was co-cultured at 4 °C with bacteriocin-producing CWBI-B28 in lean pork meat (fat content: 13%) without added nitrite, a strong antilisterial effect was observed after one week. The effect was maintained for an additional week, after which a slight and very gradual rebound was observed. Both added nitrite (20 ppm) and a high-fat content (43%) were found to antagonise this antilisterial effect, the Listeria cfu count reached after six weeks being 200 times as high in high-fat meat with added nitrite than in lean meat without nitrite. This antagonism could not be attributed to slower growth of the bacteriocin-producing strain, since CWBI-B28 grew optimally in fat-rich meat with 20 ppm sodium nitrite. Bacteriocin activity was also measured in the samples. The observed activity levels are discussed in relation to the degree of antilisterial protection conferred.     

Time-dependent depletion of nitrite in pork/beef and chicken meat products and its effect on nitrite intake estimation

The food additive nitrite (E249, E250) is commonly used in meat curing as a food preservation method. Because of potential negative health effects of nitrite, its use is strictly regulated. In an earlier study we have shown that the calculated intake of nitrite in children can exceed the acceptable daily intake (ADI) when conversion from dietary nitrate to nitrite is included. This study examined time-dependent changes in nitrite levels in four Swedish meat products frequently eaten by children: pork/beef sausage, liver paté and two types of chicken sausage, and how the production process, storage and also boiling (e.g., simmering in salted water) and frying affect the initial added nitrite level. The results showed a steep decrease in nitrite level between the point of addition to the product and the first sampling of the product 24 h later. After this time, residual nitrite levels continued to decrease, but much more slowly, until the recommended use-by date. Interestingly, this continuing decrease in nitrite was much smaller in the chicken products than in the pork/beef products. In a pilot study on pork/beef sausage, we found no effects of boiling on residual nitrite levels, but frying decreased nitrite levels by 50%. In scenarios of time-dependent depletion of nitrite using the data obtained for sausages to represent all cured meat products and including conversion from dietary nitrate, calculated nitrite intake in 4-year-old children generally exceeded the ADI. Moreover, the actual intake of nitrite from cured meat is dependent on the type of meat source, with a higher residual nitrite levels in chicken products compared with pork/beef products. This may result in increased nitrite exposure among consumers shifting their consumption pattern of processed meats from red to white meat products.     

The potential of vancomycin-resistant enterococci to persist in fermented and pasteurised meat products

Experiments with 148 isolates of vancomycin-resistant enterococci (VRE) were performed to assess their potential to persist and grow in fermented sausages and pasteurised meat products. All strains were meat isolates and Van-type A, except a single VanC1 strain. In total, 143 strains of Enterococcus faecium were involved. Eight selected strains were examined for their potential to grow at high salt and nitrite levels and at reduced pH. The same isolates were used in experiments with fermented sausages. All available strains were subjected to heating tests in meat suspensions with added curing ingredients. All but one of the eight tested isolates grew at pH 4.0 in tryptone soya broth (TSB). With the combination of 8% w/w NaCl, 400 ppm NaNO2 and 0.5% w/w glucose in the meat suspension, all isolates grew at 37 degrees C, whereas none grew at 7 degrees C even after 56 days. With the addition of 10% w/w NaCl, 200 ppm NaNO2 and 0.5% w/w glucose, still one E. faecium isolate grew at 37 degrees C, although very slowly. Overall, the strains tolerated high salt and nitrite concentrations and reduced pH very well, even beyond levels applied in the regular production of fermented and/or pasteurised meat products. The tested strains could be isolated after the fermentation and further ripening of "boerenmetworst" and "snijworst". Overall, their colony counts decreased on average about 1 log-unit over a period of 60 days after batter manufacture. All 148 isolates demonstrated a relatively weak thermal resistance compared to results for selected vancomycin-sensitive enterococci strains reported in the literature and to results collected under identical experimental conditions in this laboratory. None of the strains (log inoculation level about 5-6 ml(-1) for each isolate) could be cultured after heating at 70 degrees C for 10 min.     

Effect of Nitrite and Sorbate on Total Number of Aerobic Microorganisms in Chicken White and Dark Meat Patties

The effects of nitrite, sorbate and combinations of these two ingredients plus salt on the number of aerobic microorganisms in chicken white and dark meat patties were examined. All patties were stored at 4–5°C for 12 days. Nitrite concentrations of 400 and 2500 ppm were effective in preventing bacterial growth in chicken white meat patties while 2500 ppm was required to prevent growth in dark meat. A reduction in bacterial growth (4–10 days) was demonstrated with 100 and 150 ppm nitrite in chicken white meat patties. Four hundred ppm nitrite reduced bacterial growth in dark meat patties for 6 days. In white meat patties, the use of sorbate (0.26%) in combination with nitrite (40 ppm) was as effective in reducing bacterial growth as higher concentrations of nitrite, salt (2.5%) alone or in combination with sorbate (0.26%) or nitrite (40 ppm) inhibited bacterial growth in both white and dark meat patties during the first 4–6 days of storage.     

Antioxidant effect of turmeric powder,nitrite and ascorbic acid on stored chicken mince

This investigation was carried out to evaluate the antioxidant effect of turmeric (turmeric 1000 ppm, turmeric 5000 ppm), nitrite (nitrite 200 ppm) and ascorbic acid (ascorbic acid 500 ppm) on raw minced chicken stored at 4 ± 1 °C. Physicochemical properties [pH, water activity, cooking loss, thiobarbituric acid (TBA) value, peroxide value (PV), free fatty acid (FFA)] were evaluated on 0, 2, 4 and 6th day of storage. Highly significant differences (P < 0.01) in pH, TBA value, PV and FFA value were noticed between treatments and between storage periods. TBA values were observed to be lowest for nitrite 200 ppm and then turmeric 5000 ppm, and there was no significant difference between nitrite 200 ppm and turmeric 5000 ppm, and both were superior to ascorbic acid 500 ppm and turmeric 1000 ppm. Among different treatments, PV was found to be lowest in turmeric 5000 ppm and highest in nitrite 200 ppm. FFA value was found to be lowest in turmeric 5000 ppm and highest in ascorbic acid 500 ppm among all treated samples. It can be concluded that turmeric has potential to replace synthetic antioxidants presently used in meat processing with many added advantages.     

Influence of turkey meat on residual nitrite in cured meat products

A response surface experimental design was employed to estimate residual nitrite level at various initial nitrite concentrations, percent turkey meat in the formula, and heat quantity (F) values using a typical wiener as the test system. Pork and mechanically separated turkey were used as the meat ingredients. Residual nitrite and pH were measured at day 1, 7 days, 14 days, and 49 days after processing. Protein, fat, salt, moisture, and CIE (L*a*b*) color values were also determined. Results showed that the effect of turkey meat on residual nitrite level was significant (P < 0.01). An increased amount of turkey meat in the formula resulted in lower residual nitrite levels at a fixed pH. The residual nitrite level was initially proportional to initial nitrite concentration, but it became a nonsignificant factor during longer storage time. Differences in heat quantity had a significant effect (P < 0.05) on residual nitrite level initially. Greater heat quantity decreased residual nitrite level in finished cured meat products at a fixed pH. However, this effect became nonsignificant during longer storage. Reduction of residual nitrite in wieners because of turkey meat addition at a fixed pH was due to characteristics of the turkey tissue, but the mechanism of action remains unknown. It was also established that commercial wieners had a higher pH if poultry meat was included in the formulation.     

The influence of additives on the oxidation of pork back fat and its effect on water and fat binding in finely comminuted batters

We have found in previous experiments that slaughter-fresh processed pork back fat enhances batter stability in frankfurter-type sausages. In an attempt to clarify whether the decrease of batter stability with storage time of the fatty tissue is due to the fat oxidation a series of experiments was conducted using sodium nitrite and nitrate, 6- O -palmitoyl- l -ascorbic acid and dl-ga-tocopherol as additives to the fatty tissue. It was found that sodium nitrite and nitrate, although the first is regarded as an antioxidant in meat, had a pro-oxidant effect when added to the fatty tissue. The palmitoyl-l-ascorbic acid showed the best antioxidative activity, and the dl-α-tocopherol was less effective as an antioxidant. Contrary to its effect on the increase in fat oxidation, sodium nitrite addition gave a remarkable improvement in batter stability, expressed as jelly and fat separation, which was more pronounced on the second day of storage of the fatty tissue. The pro-oxidant effect of nitrite increased up to a concentration of 375 ppm added to the fatty tissue. Concentrations of nitrite in fatty tissue up to 125 ppm had no influence on jelly release but at higher concentrations the jelly separation decreased. All nitrite concentrations, from 62·5 to 2250 ppm, showed significantly lower fat separation than for the control treatment, especially on the eighth and 15th day of storage of the fatty tissue. The results show that fat oxidation has little effect on batter stability. Further experiments are needed to clarify the mode of action of nitrite in improving batter stability.     

Nitrite-induced injury of Listeria monocytogenes and the effect of selective versus nonselective recovery procedures on its isolation from frankfurters

Sodium nitrite (NaNO2) is used as a curing agent in frankfurters. Although previous studies have documented the bacteriostatic abilities of NaNO2 toward Listeria monocytogenes, few if any studies have been conducted that consider the possibility of sublethal injury to L. monocytogenes by exposure to NaNO2. The goals of this study were to determine whether NaNO2 has the ability to injure L. monocytogenes, to determine whether nitrite injury is reversible, and to compare the recovery of L. monocytogenes from frankfurters containing nitrite with Listeria repair broth (LRB) and University of Vermont modified Listeria enrichment broth (UVM). NaNO2, when used at concentrations of 100 and 200 ppm, was found to injure L. monocytogenes. The injury was completely reversible, or growth of uninjured Listeria occurred in LRB when injury was between 98.5 and 98.7%. However, total recovery was not observed in LRB when injury exceeded 99%. UVM was unable to reverse the effects of nitrite-injured L. monocytogenes. With respect to time, inoculum, and meat type, LRB was found to be consistently superior to UVM at recovering L. monocytogenes from frankfurters. Nitrite injury might be a factor influencing detection and recovery of L. monocytogenes from frankfurters.     

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.     

Effect of added water, sodium erythorbate and storage time on the functional properties of prerigor beef preblends in a model system

Singular and combined effects of added water, sodium erythorbate and storage time on salt soluble protein extractability, bacteriological and chemical characteristics of preblended hot-boned beef were evaluated. Waterholding and gel forming capacities of preblended hot-boned beef containing either 0, 10 or 20% added water were determined. Significant interactions between added water level and storage time on microbial counts and between sodium erythorbate level and storage time on thiobarbituric acid values and residual nitrite levels were noted. The presence of sodium erythorbate resulted in a more (P < 0·05) rapid rate of nitrite disappearance, but it did not affect (P > 0·05) microbial counts. Salt-soluble protein extractability was not affected (P > 0·05) by added water, but more protein could be extracted with increasing storage time. A trend existed to suggest that the presence of added water in the meat preblends slightly improved the gel formation and waterholding capacities.     

发酵牛肉调味基料在牛肉饼中的应用效果

冷冻牛骨肉末经热-压浸提、酶解、发酵和美拉德反应后制成发酵牛肉调味基料（fermented beef flavoring,FBF）,以新鲜牛前肩肉为原料,加入不同比例腌制剂制成牛肉饼,分别为阴性对照（negative control,NC）组（既不添加NaNO2又不添加FBF）、阳性对照（positive control,PC）组（添加不同比例的NaNO2）及实验组。对牛肉饼进行感官评价后于20 ℃条件下贮藏,测定贮藏期间牛肉饼的红度值（a*）、pH值、硫代巴比妥酸反应物（thiobarbituric acid reactive substance,TBARs）值及亚硝酸盐残留量。结果表明：与NC组相比,PC组和实验组牛肉饼色泽红润,口感香嫩,风味得到明显改善;只添加FBF的实验组牛肉饼a*较高,TBARs值和亚硝酸盐残留量较低;同时添加NaNO2和FBF的牛肉饼口感、色泽及风味等品质均有所提高,且20 g/kg FBF和0.05 g/kg NaNO2复配制成的牛肉饼品质最好。     

The influence of nitrite and nitrate on microbial, chemical and sensory parameters of slow dry fermented sausage

Nitrate and/or nitrite are used in the manufacture of dry-fermented sausages. However, research has mainly been focusing on nitrite and its effect on flavour development whereas little attention has been paid to nitrate. The aim of the present work was to study the effect of nitrate and nitrite as curing salts on the quality of a slow fermentation process. Two different batches containing nitrate or nitrite were manufactured. Microbial and chemical parameters were monitored during ripening and after vacuum packed storage, as well as their fatty acid composition and their profile of volatile compounds. The oxidation, measured as TBARS (Thiobarbituric acid reactive substances), was greater in the samples with added nitrite than in the samples with added nitrate. FFA (free fatty acids) release was higher in the samples containing nitrite throughout the process. Volatile compounds arising from amino acid degradation and carbohydrate fermentation were generated at higher levels in the samples with added nitrate, probably due to the higher population of microorganisms in these samples and the effect of nitrate on their metabolism.     

Sensory and Chemical Characteristics of Pork Chops as Affected by Precooking, Curing and Frozen Storage

Four processing procedures were compared as methods of reducing warmed-over flavor (WOF) of pork chops during frozen storage for 84 days, These procedures were (1) oven-broiled chops, (2) chops from loins precooked with no additives, (3) chops from loins cured with 0.5% salt and 40 ppm NaNO2 and precooked, and (4) chops from loins cured with 2% salt and 120 ppm NaNO2 and precooked. Samples were evaluated by the TBA test, Warner-Bratzler shear, hydroxyproline assay and by sensory analysis after frozen storage at -18°C. Chops from the three precooked treatments were more tender than oven-broiled chops. Nitrite inhibited WOF development of precooked chops during frozen storage and 40 ppm nitrite was nearly as effective as 120 ppm.     

Factors controlling the growth of Clostridium botulinum types A and B in pasteurized cured meats VI. Nitrite monitoring during storage of pasteurized pork slurries

Residual nitrite levels were monitored during storage for up to 6 months, in a model pork slurry system used to study the relative effects of curing ingredients and additives used in pasteurized cured meats to control the growth of Clostridium botulinum.
In 'low' pH slurries the rate of loss of nitrite fell with reducing storage temperature. Less residual nitrite remained after HIGH heat treatment but the rate of loss of that residual nitrite was slower during storage than nitrite remainly after LOW heat treatment. Inclusion of nitrate resulted in higher residual nitrite levels, particularly after HIGH heat and if stored below 20°C. If isoascorbate was added nitrite became undetectable within circa 30 days, even when nitrate had been added. The rate of loss of nitrite was slower in 'high' pH slurries (pH 6.3–6.8).
Monitoring levels of nitrite in the product soon after production would detect its accidental overuse but monitoring nitrite in the product during distribution or at retail, without knowledge of the composition and prior history of the product, gives little indication of the amount used at manufacture. The level of residual nitrite was not directly related to the ability of the curing mixture to control the growth of CI. botulinum types A and B. Some slurries in which C1. botulinum grew least during 6 months' storage contained no residual nitrite because isoascorbate was also present.     

Effect of frozen and dried leek on processing and quality characteristics of Greek traditional sausages

Blanching of leek at boiling temperature for 1min reduced (p<0.05) the nitrate content. Freezing of leek at -18°C and storage for 5 months, with or without vacuum, also reduced (p<0.05) the nitrate content, while drying at 85°C for 2h and storage for 5 months, with or without vacuum, had no effect (p>0.05) on nitrate content. Frozen leek as a whole plant was unsuitable for the production of traditional sausages. The most appropriate level of dried leek for sausage production was 20g/kg of meat mixture. The nitrate content of sausages with frozen and dried leek ranged on the 7th day from 24.5±14 to 36.3±13ppm and the nitrite content from 1.4±0.4 to 2.6±1ppm. Sausages with dried leek had better (p<0.05) colour, higher (p<0.05) pH and lower (p<0.05) TBA values. Sausages with frozen and dried leek had the same (p>0.05) sensory attributes as those produced with fresh leek. Vacuum packaging affected (p<0.05) the odour of fresh sausages with frozen and dried leek and the overall acceptability of fresh sausages with frozen leek. Sausages with frozen and dried leek stored under vacuum had higher scores for sensory attributes, which were not always significant.     

Microbial formation of nitrite-cured pigment,nitrosylmyoglobin, from metmyoglobin in model systems and smoked fermented sausages by<Emphasis Type="Italic"> Lactobacillus fermentum</Emphasis> strains and a commercial starter culture

Two Lactobacillus fermentum strains (JCM1173 and IFO3956) were evaluated for their ability to generate nitrosylated derivatives of myoglobin either in broth media or fermented sausages. For comparison, a commercial starter culture was also included. All bacteria species investigated converted brown metmyoglobin into red myoglobin derivatives when incubated separately in broth, but only the two lactobacilli showed a signal for nitrosylmyoglobin as measured by electron spin resonance spectroscopy. In smoked sausages with added bacteria culture the highest amount of nitrosylmyoglobin was observed in the centre of sausage with added L. fermentum, but colour formation in sausages with 60 ppm of nitrite added was more pronounced. An outer peripheral zone of all fermented sausages contained levels of nitrosylmyoglobin comparable to nitrite-cured sausages. Nitrogenous gasses from smoke may, however, cause this zone to be formed. Depending on a further optimisation of the processing parameters, the bacteria's ability to generate NO could form the basis for production of cured meat products without the use of nitrite/nitrate.     

The effects of nitrite on the survival of Clostridium sporogenes and the autoxidation properties of the Kavurma

Kavurma is a traditional cooked (fried) meat product manufactured to preserve meat. Some bacterial genera, e.g., clostridia are important in kavurma. The objective of this study was to determine the influence of nitrite and the traditional cooking process on the survival and proliferation of Clostridium botulinum and the autoxidation properties of the kavurma. For this purpose, Clostridium sporogenes having similar characteristics to C. botulinum was used, and the samples were inoculated with 10(6) CFU/g C. sporogenes cells before the traditional cooking. The final products were packaged and stored under refrigeration for 6 months, and then the oxidation parameters (TBA, peroxide and free fatty acid values) and C. sporogenes counts of samples were determined. It was observed that C. sporogenes could survive during the traditional cooking process and storage. However, counts decreased during storage; for example, nitrite containing samples initially had 3.21logCFU/g C. sporogenes and 2.73logCFU/g at the end of storage. While nitrite had a slight antimicrobial effect on clostridia, it significantly reduced the TBA, peroxide and FFA values of the samples. In conclusion, it is suggested that addition of 100ppm of nitrite might be useful in kavurma processing because of its role in limiting oxidation as well as its antimicrobial effect.