Residual Nitrite Content Research Articles

Sensory profile and color and oxidative stabilities of sliced restructured cooked hams with added S-nitroso-N-acetylcysteine as a nitrite replacement

The objective of this study was to evaluate the effects of replacing sodium nitrite by S-nitroso-N-acetylcysteine (NAC-SNO) at different addition levels (50, 150, and 300mg of equivalent nitrite–Neq/kg) on the sensory profile and on the quality characteristics of restructured cooked hams during sliced storage (up to 60 days at 4°C). The addition of NAC-SNO did not affect (P > 0.05) the pH of the products and resulted in lower (P < 0.05) residual nitrite content (1.79 ± 0.61mg/kg) and higher (P < 0.05) TBARS values (0.86 ± 0.44mg MAD/kg) than nitrite added samples (8.43 ± 2.37mg/kg and 0.66 ± 0.25mg MAD/kg, respectively). During storage, an increasing trend in lipid oxidation was observed regardless of the curing agent used. The addition of 50mg NEq/kg of NAC-SNO resulted in products with a more yellowish color tone (higher h values) and less intensity (lower C* values) than all the other products. The equimolar addition of 150mg NEq/kg of NAC-SNO resulted in a similar pink color acceptance to nitrite; however, they were characterized by a higher (P < 0.05) characteristic flavor and aroma intensity and obtained greater (P < 0.05) sensory acceptance than nitrite. The addition of 150mg NEq/kg of NAC-SNO was suggested as a substitute for nitrite to achieve the desired stability and sensory characteristics of cooked cured products.

Hyperspectral Imaging Combined with Machine Learning Can Be Used for Rapid and Non-Destructive Monitoring of Residual Nitrite in Emulsified Pork Sausages

The non-destructive and rapid monitoring system for residual nitrite content in processed meat products is critical for ensuring food safety and regulatory compliance. This study was performed to investigate the application of hyperspectral imaging in combination with machine learning algorithms to predict and monitor residual nitrite concentrations in emulsified pork sausages. The emulsified pork sausage was formulated with 1.5% (w/w) sodium chloride, 0.3% (w/w) sodium tripolyphosphate, 0.5% (w/w) ascorbic acid, and sodium nitrite at concentrations of 0, 30, 60, 90, 120, and 150 mg/kg, based on total sample weight. Hyperspectral imaging measurements were conducted by capturing images of the cross-sections and lateral sides of sausage samples in a linescan mode, covering the spectral range of 1000–2500 nm. The analysis revealed that higher nitrite concentrations could influence the protein matrix and hydrogen-bonding capacities, which might cause increased reflectance at approximately 1080 nm and 1280 nm. Machine learning models, including XGBoost, CATboost, and LightGBM, were employed to analyze the hyperspectral data. XGBoost demonstrated the best performance, achieving an R2 of 0.999 and a root mean squared error of 0.095, highlighting its high predictive accuracy. This integration of hyperspectral imaging with advanced machine learning algorithms offers a non-destructive and real-time method for monitoring residual nitrite content in processed meat products, noticeably improving quality control processes in the meat industry. Additionally, real-time implementation in industrial settings could further streamline quality control and enhance operational efficiency. Further research should focus on validating these findings with larger sample sizes and more diverse datasets to ensure robustness.

Investigating the Effects of Pink-Generating Ligands on Enhancing Color Stability and Pigment Properties in Pork Sausage Model Systems Cured with Sodium Nitrite or White Kimchi Powder.

In this study, we investigated the effects of different nitrite sources (sodium nitrite or white kimchi powder) and pink-generating ligands (cysteine, histidine, or nicotinamide) on the development and stability of cured meat color in pork sausage model systems over 30 d of refrigerated storage. The samples were prepared in a 2 × 3 factorial design with two nitrite sources and three ligands, and their physicochemical properties were evaluated on days 0, 15, and 30. Although white kimchi powder induced cured color development similar to that of synthetic sodium nitrite, it resulted in higher cooking loss and lower residual nitrite content in cured pork sausages (p < 0.05). The addition of cysteine resulted in significantly higher CIE a* values, cured meat pigment, and curing efficiency than histidine and nicotinamide (p < 0.05), while yielding lower pH values, residual nitrite content, and total pigment content (p < 0.05). The storage duration significantly reduced the residual nitrite and total pigment contents of the products. These findings suggest that white kimchi powder can serve as a natural alternative to sodium nitrite in pork sausage models and that the incorporation of cysteine has a favorable impact on the development and enhancement of cured meat color.

Effects of l‐arginine/l‐lysine on physicochemical properties of sodium‐reduced Cantonese sausage without exogenous phosphate addition

SummaryThe study inquired the influences of l‐arginine and l‐lysine on the physicochemical properties (including weight loss rate, water activity, texture, colour, lipid and protein oxidation, residual nitrite content and total volatile basic nitrogen (TVB‐N) content) of low‐sodium and low‐phosphate Cantonese sausage during the 1‐ and 7‐day storage. The results showed that the addition of l‐arginine or l‐lysine reduced the weight loss rate, TBARS content, carbonyl group content and residual nitrite level, slightly decreased water activity, and enhanced L*, a* and b* values. Compared to the control, 0.3% l‐arginine or l‐lysine declined hardness and chewiness, while 0.6% l‐arginine or l‐lysine elevated these two parameters. However, the addition of l‐arginine or l‐lysine also led to an increase in TVB‐N content. Overall, l‐arginine and l‐lysine improved the qualities of low‐sodium and low‐phosphate Cantonese sausage, which might be attractive to meat product manufacturers.

Enhancing quality control in emulsion-type sausage production: Predicting chemical composition of intact samples with near infrared spectroscopy

This research actively explores the potential of near infrared spectroscopy (NIR) for analyzing the chemical composition of emulsion-type sausages, focusing on critical factors like residual nitrite, moisture, protein, and fat content. To establish robust and generalizable models, we utilized a dataset of 100 experimentally prepared sausages encompassing a wide range of pork back fat replacement levels (5%, 15%, 30%, 45%, and 60%) and added sodium nitrite amounts (0, 80, 125, 250, and 375 ppm). An external validation set of 20 commercially sourced sausages further assessed the model’s real-world applicability. Partial least squares (PLS) regression calibration models with multiplicative scatter correction (MSC) pre-treatment demonstrated impressive accuracy for moisture (RMSECV = 0.57%, RPD = 9.8), fat (RMSECV = 1.17%, RPD = 9.5), and protein (RMSECV = 0.30%, RPD = 7.6). While residual nitrite prediction presented challenges due to its inherent complexity, the external validation yielded a competitive root mean square error of prediction (RMSEP) of 12.02 ppm, surpassing the average performance reported in similar studies (RMSEP ∼15 ppm) by 3 ppm. Importantly, sample homogenization did not significantly affect parameter prediction, highlighting the robustness of the NIR-based approach. These findings suggest that NIR spectroscopy, with its non-destructive, rapid, and cost-effective nature, could provide valuable tools for quality control and monitoring in the emulsion-type sausage industry. More importantly, improved nitrite prediction could pave the way for enhanced precision and control in sausage production, ultimately contributing to improved food safety and sustainability.

The Potential Substitution of Oyster Shell Powder for Phosphate in Pork Patties Cured with Chinese Cabbage and Radish Powder.

The use of natural ingredients in meat processing has recently gained considerable interest, as consumers are increasingly attracted to clean-label meat products. However, limited research has been conducted on the use of natural substitutes for synthetic phosphates in the production of clean-label meat products. Therefore, this study aimed to explore the potential of oyster shell powder as a substitute for synthetic phosphates in pork patties cured with Chinese cabbage or radish powders. Four different groups of patties were prepared using a combination of 0.3% or 0.6% oyster shell powder and 0.4% Chinese cabbage or radish powder, respectively. These were compared with a positive control group that contained added nitrite, phosphate, and ascorbate and a negative control group without these synthetic ingredients. The results showed that patties treated with oyster shell powder had lower (p<0.05) cooking loss, thickness and diameter shrinkage, and lipid oxidation than the negative control but had lower (p<0.05) residual nitrite content and curing efficiency than the positive control. However, the use of 0.6% oyster shell powder adversely affected the curing process, resulting in a decreased curing efficiency. The impact of the vegetable powder types tested in this study on the quality attributes of the cured pork patties was negligible. Consequently, this study suggests that 0.3% oyster shell powder could serve as a suitable replacement for synthetic phosphate in pork patties cured with Chinese cabbage or radish powders. Further research on the microbiological safety and sensory evaluation of clean-label patties during storage is required for practical applications.

Comprehensive metagenomic and enzyme activity analysis reveals the inhibitory effects and potential toxic mechanism of tetracycline on denitrification in groundwater

The widespread use of tetracycline (TC) inevitably leads to its increasing emission into groundwater. However, the potential risks of TC to denitrification in groundwater remain unclear. In this study, the effects of TC on denitrification in groundwater were systematically investigated at both the protein and gene levels from the electron behavior aspect for the first time. The results showed that increasing TC from 0 to 10 µg·L−1 decreased the nitrate removal rate from 0.41 to 0.26 mg·L−1·h−1 while enhancing the residual nitrite concentration from 0.52 mg·L−1 to 50.60 mg·L−1 at the end of the experiment. From a macroscopic view, 10 µg·L−1 TC significantly inhibited microbial growth and altered microbial community structure and function in groundwater, which induced the degeneration of denitrification. From the electron behavior aspect (the electron production, electron transport and electron consumption processes), 10 µg·L−1 TC decreased the concentration of electron donors (nicotinamide adenine dinucleotide, NADH), electron transport system activity, and denitrifying enzyme activities at the protein level. At the gene level, 10 µg·L−1 TC restricted the replication of genes related to carbon metabolism, the electron transport system and denitrification. Moreover, discrepant inhibitory effects of TC on individual denitrification steps, which led to the accumulation of nitrite, were observed in this study. These results provide the information that is necessary for evaluating the potential environmental risk of antibiotics on groundwater denitrification and bring more attention to their effects on geochemical nitrogen cycles.

Production of restructured beef jerky using blood plasma solutions activated by non-thermal atmospheric plasma

Abstract The effect of blood plasma powder (2.5, 5, and 7.5% w/w in water) activated using non-thermal atmospheric plasma (T1, T2, and T3, respectively) was investigated as a nitrite source in the production of restructured beef jerky. A group without a nitrite source (NC) and a group cured with 100 ppm of sodium nitrite (PC) were used as negative control and positive control groups, respectively. The nitrite content of the plasma-activated solutions was adjusted to match that of the positive control by calculating the required plasma treatment time, based on previous studies. The obtained results showed that addition of treated solutions with nonthermal plasma for a 70 min, at a level of 20% in relation to the meat, can have beneficial effects on nitrosylhemochrome content, redness, and TBARS values of restructured jerky. These effects were statistically comparable (p≥0.05) to sodium nitrite-cured samples. Furthermore, compared to the PC group, the T1, T2, and T3 treatments exhibited significantly lower water activity and higher protein content (p&lt;0.05). The T2 and T3 treatments also showed increased lightness and shear force values (p&lt;0.05) compared to the control groups (NC and PC). It should be noted that the T3 group had the highest (p&lt;0.05) residual nitrite content among all the samples. However, a sensory analysis is necessary to assess consumer acceptance with regard to differences in the odor profile of the treatments, according to the Principal Components Analysis (PCA).

Effects of Coprinus comatus (chicken drumstick mushroom) on the quality characteristics of low nitrite-backfat Cantonese sausages

This study investigated the chemical composition, physicochemical properties, antioxidant activity and volatile compounds of low nitrite-backfat Cantonese sausages, and the antimicrobial effects, protein decomposition, lipid peroxidation and sensory properties were assessed during 7 d of refrigeration. Four independent replications of sausages were produced to compare groups: the Control and four groups with various levels of Coprinus comatus (CC) and backfat (BF) contents added (Sample 1: 50 g/kg CC and 150 g/kg BF; Sample 2: 100 g/kg CC and 100 g/kg BF; Sample 3: 150 g/kg CC and 50 g/kg BF and Sample 4: 200 g/kg CC). The results showed that the inclusion of CC improved (P < 0.05) the protein content (28.88–32.14%), ash content (2.51–3.56%), dietary fiber (0.87–1.65%), b* values (18.65–19.04), antioxidant activity (75–85% in DPPH and 20–25% in ABTS), and volatile compounds (up to 48 types), but reduced (P < 0.05) the cohesiveness (0.41–0.48), chewiness (86.8–47), hardness (5884-1558), and residual nitrite content (<6 mg/kg) of the sausage. There were no significant differences (P > 0.05) between the treatments in terms of moisture, water activity, pH, and springiness of the sausages. Sausages incorporated with C. comatus showed a decrease in microbiological counts, total volatile nitrogen, and thiobarbituric acid reactive substances during 7 d of refrigeration compared to the Control. Sausage formulation with 50% C. comatus and 50% back fat earned the best overall acceptability by considering the sensorial properties.

The Effect of a Combination of Nitrite with Lactate, and Sorbate on Physical, Chemical, Antioxidant and Sensory Properties of Beef Mortadella during Storage

This study aimed to evaluate the effect of a combination of nitrite with lactate and/or sorbate on the physical, chemical antioxidant, and sensory properties of beef mortadella during storage. Five treatments (Tr1, Tr2, Tr3, Tr4, and Tr5) of beef mortadella were prepared and stored at 4°C. Tr1 and Tr2 with 120ppm and 60ppm of nitrite (NaNO2) respectively, were controls. Tr3 was prepared with the addition of Na-nitrite and Na-lactate, Tr4 with Na-nitrite and K-sorbate, and Tr5 with a combination of all of them. Samples were tested for chemical composition, pH, hunter color, thiobarbituric acid values (TBA), residual nitrite concentration, and sensory characteristics during storage. Additionally, the residual nitrite content of 12 different meat products was estimated. Nitrite had a slight effect on the chemical composition. At the end of storage, TBA values did not exceed 2mg/Kg malondialdehyde in all treatments. However, Tr2 and Tr5 had lower TBA values. The highest pH value recorded was for Tr5 (6.33). A sharp decrease in nitrite level was found in all treatments. During storage, Tr3, Tr4, and Tr5 were more stable in terms of color than the control samples. Treatments with 60ppm nitrite only, or combined with an organic acid, were well-accepted from a sensorial aspect. Flavor and aroma scores were statistically similar with ratings between 5.89-6.47/9. Nitrite reduction in meat products is considered a markedly healthier practice.

Combined Effects of Parsnip Fermented Juice and Hawthorn Extract Regarding Pork Mince Stability: Physico-Chemical and Microbiological Aspects

Parsnip fermented juice (PFJ) and hawthorn extract (HE) were identified as natural nitrite and antioxidant sources for pork mince. This study aimed to determine the effects of varying levels of HE added to a constant concentration of PFJ on lipids stability, heme pigment conversion degree, residual nitrite content, and spoilage bacteria growth, during refrigeration, compared with the combined effect of synthetic nitrite and sodium ascorbate (SA). Pork mince was formulated in six different ways with sterile distilled water (NC), 100 ppm synthetic nitrite and 50 ppm SA (PC), PFJ in the concentration of 100 ppm NO2− (T1), constant level of PFJ (100 ppm NO2−), and increased level of HE, 50, 25 and 10 ppm GAE (T2, T3 and T4). During the experiment, pH increased for all the treatments, but the addition of PFJ alone or in combination with HE, it was maintained below the NC pH value. The lowest TBARS values and the highest PUFA concentrations were found in the T3, T4, and PC treatments. Of all the samples, the lowest residual nitrite values were found for T2. The highest NO-heme values were found for T2 and PC. After 9 days of storage, TVC results were higher than 5.69 logs CFU/g for all treatments. Overall, the obtained results showed that the combination of HE and PFJ could be a promising natural preservative for minced meat that could replace synthetic preservatives.

Effects of natural nitrite sources from arugula and barberry extract on quality characteristic of heat-treated fermented sausages

This study was designed to compare the effects of natural nitrite sources from the arugula leaves (arugula extract and pre-converted arugula extract) and the use of barberry extract (BE) in heat-treated fermented sausage formulations. Eight different sausages were manufactured as follows: pre-converted arugula extract (PA), arugula extract (A), pre-converted arugula extract + BE (PAB), arugula extract + BE (AB), nitrite +BE (POB), no nitrite+ BE (NEB), also positive and negative control groups were prepared with (POC) or without nitrite (NEC). The addition of arugula and barberry extracts reduced the residual nitrite content, in fact PAB had the lowest value with a reduction ratio of 47%. The addition of BE lowered the lipid oxidation compared to other counterparts. The use of arugula extract or pre-converted arugula extract resulted in a lower carbonylation than nitrite free samples. The use of natural extracts lowered the a* and b* values compared to control. At the end of the storage, no differences were observed on the overall acceptability of all samples. Combined use of barberry extract with arugula and pre-converted arugula extracts could be used as alternative novel curing agent in heat-treated fermented sausages.

Investigation of the Possibility of Listeria monocytogenes Growth in Alternatively Cured Cooked Sausages—A Case Study

The aim of this study was to investigate the possibility of Listeria monocytogenes growth in cooked sausages produced in the same meat processing plant without or with a direct nitrite addition (alternatively cured, AC, and nitrite cured, control). The AC and control sausages were inoculated with a mix of three L. monocytogenes strains. Products (n = 24 sausages for each product type) were vacuum-packed and stored for 10 days at 6 °C. Residual nitrite and salt contents, water activity and the number of L. monocytogenes were determined in products. A higher nitrite content was found in the control (44.9 mg/kg) compared with AC (12.1 mg/kg). Significantly higher L. monocytogenes counts at the 6th and the 8th day were noted in AC sausages, however at the 10th day they did not differ significantly between the treatments (2.96 and 3.27 log10 CFU/g in the control and AC, respectively). AC sausages showed a growth potential value of 0.64, which indicates the possibility of L. monocytogenes growth on the surface of alternatively cured products. In contrast, a growth potential value of 0.21 was found in control sausages, which indicates that nitrite cured sausages did not support the pathogen growth at 6 °C.

Evaluation of the residual nitrite concentrations of locally produced and imported meat products in Kosovo

The use of food additive nitrite as curing agents is common in meat products, but their concentration in these products has raised the interest of researchers, because of the possible toxicity to humans. The aim of this study is to assess the nitrite concentration in meat products, which are highly used by all population groups in Kosovo. A total of 44 different meat products samples available on sale to the population, were assessed for residual nitrite using the spectrophotometric method that uses absorption in visible part of spectra. The amount of residual nitrites was detected in 19 (43%) of the samples, which included beef and chicken sausages, chicken &amp; beef salami as well as beef prosciutto samples. The nitrite residue ranged between 0.1 and 11.5 mg/kg and was below the limits on the concentration of nitrites in meat products established by EU regulation 601/2014. Although these findings show that, the nitrite residue in the analyzed meat products is within the permitted limits, the highest presence of residual nitrite in industrial and low-cost meat products indicates a need for further assessments of nitrite exposure among consumers.

Green Technology for Pork Loin Wet Curing-Unconventional Use of Cow and Soy Milk Treated with Non-Thermal Atmospheric Plasma.

This study was conducted to evaluate the possibility of using plasma-activated cow and soy milk powders as a substitute for sodium nitrite for wet curing of pork meat (m. longissimus thoracis et lumborum). Pork loin slices were cured for 4 d at refrigerate conditions in four brines: water + salt (NC group), water + salt + sodium nitrite (PC group), water + salt + plasma-activated cow milk powder (B1 group), and water + salt + plasma-activated soy milk powder (B2 group). Importantly, brines from groups PC, B1, and B2 were characterized by the same concentration of NO2− ions (200 ppm). Results show that samples from B1 and B2 groups had significantly (p < 0.05) higher values of redness, nitrosylhemochrome content, and lower values of thiobarbituric acid reactive substances (TBARS) compared to samples from the NC group. At the same time, the groups cured with alternative curing agents were characterized by lower residual nitrite content with regard to groups cured with NaNO2. No significant differences (p ≥ 0.05) were found in pH and shear force values among the treatments. Finally, the aroma profile of the samples from groups B1 and B2 was similar to the aroma profile of the samples from the PC group (the aroma differed by a maximum of 1.73% in the case of brine containing plasma-activated cow milk powder) but differed significantly from the NC group (the aroma differed in 97.21%). Due to the higher nitrite depletion in the final product, while maintaining the quality parameters similar to traditionally cured pork loins, both alternative curing agents can be recommended, with a predominance of plasma-treated soy milk.

Easy Nitrite Analysis of Processed Meat with Colorimetric Polymer Sensors and a Smartphone App.

We have developed an in situ methodology for determining nitrite concentration in processed meats that can also be used by unskilled personnel. It is based on a colorimetric film-shaped sensory polymer that changes its color upon contacting the meat and a mobile app that automatically calculates the manufacturing and residual nitrite concentration by only taking digital photographs of sensory films and analyzing digital color parameters. The film-shaped polymer sensor detects nitrite anions by an azo-coupling reaction, since they activate this reaction between two of the four monomers that the copolymer is based on. The sensory polymer is complemented with an app, which analyzes the color in two different digital color spaces (RGB and HSV) and performs a set of 32 data fittings representing the concentration of nitrite versus eight different variables, finally providing the nitrite concentration of the test samples using the best fitting curve. The calculated concentration of nitrite correlates with a validated method (ISO 2918: 1975) usually used to determine nitrite, and no statistically significant difference between these methods and our proposed one has been found in our study (26 meat samples, 8 prepared, and 18 commercial). Our method represents a great advance in terms of analysis time, simplicity, and orientation to use by average citizens.

Production of nitrite-free frankfurter-type sausages by combining ε-polylysine with beetroot extracts: An assessment of microbial, physicochemical , and sensory properties

The current study investigated the utilization of ε-polylysine (ε-PL) and beetroot extract (BE) as suitable nitrite substitutes in frankfurter-type sausages packaged in vacuum polyethylene bags. The sample's technological, safety, antimicrobial, and organoleptic attributes were analyzed during 30 days of storage at 4 °C. Compared with controls, the sausages containing ϵ-PL with BE had no significant differences in the water activity and proximate composition. The results showed that the T5 and T4 samples had the highest residual nitrite and total phenolic contents at day 45. Incorporating ε-PL and BE into frankfurter-type sausages prevented the increase of pH and maintained samples' pink color and texture consistency during storage. T3 and T4 samples could effectively delay the growth of total viable count, coliform, Clostridium perfringens, mold, and yeasts within acceptable limitations during refrigerated storage.

Investigation of textural and physicochemical changes during the manufacturing process of pastırma, a dry-cured meat product.

The changes in textural and physicochemical properties and stability of meat proteins during the production of pastırma were studied. Samples taken at different production stages (raw material, curing, first drying, second drying and final product) were analyzed. The pH decreased at the end of the curing but increased after the first and second drying. While moisture content and water activity decreased throughout the pastırma production, salt content and Thiobarbituric acid-reactive substances (TBARS) increased. Production stages affected the free fatty acids, residual nitrite content and color parameters (P < 0.01). These results showed that considerable physicochemical changes occurred in the production stages of pastırma. The denaturation temperatures for myosin and actin decreased at the end of the curing, however, no denaturation peak for myosin was observed in the later stages. Hardness, cohesiveness and chewiness increased throughout the pastırma production. Warner-Bratzler (WB) shear force increased at the end of the first drying and in the final product. These results are important in terms of obtaining the desired textural properties in the final product. Also, remarkable correlations were detected among the determined properties during the manufacturing process. The study provided considerable findings for the development of industrial pastırma production.

Assessment of Japanese radish derivatives as nitrite substitute on the physicochemical properties, sensorial profile, and consumer acceptability of restructured cooked hams

This study aimed to evaluate the technological and sensory properties of restructured cooked hams prepared with natural curing agents (0.5% radish powder, HRP; 3% radish juice, HRJ; and 0.5% radish pulp powder, HRPP) and with 40 and 150 mg/kg sodium nitrite (HN40 and HN150, respectively). No difference was observed for pH, proximate composition, or cooking loss. Higher residual nitrite contents were observed in the HN150, followed by the radish derivatives hams and HN40. All radish derivatives hams had a similar hue (h) color to HN40, but the h values of HRJ also did not differ from the HN150 ones. The stability of the cured color was not affected. Consumers perceived a non-characteristic aroma and flavor in the radish derivatives hams, but the HRJ had the best acceptance scores. The HRJ appearance was similar to the HN150, and the other sensory attributes were like the HN40. The potential use of radish derivatives, especially radish juice, as natural curing agents was confirmed.

Effect of plant polyphenols on the physicochemical properties, residual nitrites, and N-nitrosamine formation in dry-fried bacon

Tea polyphenol (TP), apple polyphenol (AP), and cinnamon polyphenol (CP) are all enriched with antioxidant components, present enormous potential as natural antioxidants in meat products. The objective of this study was to evaluate the physicochemical properties, residual nitrites, and formation of N-nitrosamine (NA) in dry-fried bacons with three aforementioned plant polyphenols and ascorbic acid (AA). The results show that both plant polyphenols and AA significantly reduced pH, lipid oxidation and residual nitrite content when compared to the control (P < 0.05). Only AP exhibited a protective effect against protein oxidation-induced damage in bacon, and N-nitroso-methyl phenylamine (NMPhA) contents were significantly affected by plant polyphenols (P < 0.05). Bacon containing 300 mg/kg AP produced less thiobarbituric acid reactive substance (TBARS) (0.59 MDA/kg), carbonyl contents (2.30 nmol/mg protein) and NMPhA formation (1.211 ng/kg). In conclusion, plant polyphenols, particularly AP, have the potential to be used as natural antioxidants for reducing oxidation and nitrite application level while also improving the safety of bacon.