Clean Label Meat Technology: Pre-Converted Nitrite as a Natural Curing

Mechanisms underlying the changes in the structural, physicochemical, and emulsification properties of porcine myofibrillar proteins induced by prolonged pulsed electric field treatment

This study aimed to explore how pulsed electric field (PEF) treatment affects the structural, physicochemical, and emulsification properties of porcine-derived myofibrillar proteins (MPs). Increasing PEF treatment induced partial polarization and protein unfolding, resulting in notable denaturation that affected both the secondary and tertiary structures. PEF treatment also improved the solubility and emulsification ability of MPs by reducing their pH and surface hydrophobicity. Confocal laser scanning microscopy confirmed the effective adsorption of MPs and PEF-treated MPs at the oil/water interface, resulting in well-fabricated Pickering emulsions. A weak particle network increased the apparent viscosity in short-term PEF-treated Pickering emulsions. Conversely, in emulsions with long-term PEF-treated MP, rheological variables decreased, and dispersion stability increased. These results endorse the potential application of PEF-treated porcine-derived MPs as efficient Pickering stabilizers, offering valuable insights into the creative use of PEF for enhancing high-quality meat products, meeting the increasing demand for clean-label choices.

Clean labelling sodium nitrite at pilot scale: In-situ reduction of nitrate from plant sources and its effects on the overall quality and safety of restructured cooked ham

Growing health and environmental concerns have increased demand for all-natural products, with a focus on clean labelling. Sodium nitrite is the most widely used additive in the meat industry because it imparts the typical cured flavour and colour to meat products and, most importantly, their microbiological safety. However, due to health concerns, the European Commission is proposing revised regulations to reduce nitrate and nitrite levels in meat products. As a result, the meat industry is actively seeking alternatives. This study explored the production of four cooked hams utilising nitrate-rich vegetable sources combined with two different nitrate-reducing commercial food cultures, alongside a control ham prepared with sodium nitrite (150 ppm). Microbiological, physico-chemical (pH, water activity, nitrate and nitrite concentration, lipid profile, lipid oxidation) and sensory (texture and colour profile) characterisation of the products was carried out. Challenge tests for Listeria monocytogenes, Clostridium sporogenes and Clostridium perfringens have been performed to assess the growth of pathogens, if present in the products. Results revealed comparable microbiological and physico-chemical profiles across ham formulations, with minor differences observed in colour parameters for sample C. The sensory analysis showed that for the pilot ham formulations A and D, there were no significant differences in consumer perception compared to the control ham. In the challenge tests, L. monocytogenes levels were similar in both control and tested hams. There were no significant differences in C. sporogenes and C. perfringens counts at any temperature or between test and control samples. These results indicate that this technology has a potential future in the cured meat sector, as regulators mandate the reduction of added synthetic chemicals and consumers seek healthier and more natural ingredients in their daily diets.

Reduction of N-nitrosamine in cured ham using atmospheric cold plasma-treated cauliflower powder

The effects of cauliflower treated with atmospheric cold plasma (ACP), as a natural nitrite source, on the curing of ground ham and nitrosamine formation were investigated. Ground ham was prepared using sodium nitrite and ACP-treated cauliflower powder (PTCP) to achieve initial nitrite concentrations of 60 and 100 mg/kg, respectively. ACP treatment generated nitrite in cauliflower but significantly reduced the antioxidant activity (P < 0.05). As a nitrite source, PTCP had similar effects as sodium nitrite in the development of cured color in ground ham, with a comparable residual nitrite content (P ≥ 0.05). Three nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and N-nitrosopyrrolidine (NPYR), were detected in ground ham. NPYR formation was significantly lower in ground ham treated with PTCP at an initial nitrite concentration of 100 mg/kg (P < 0.05). Therefore, the use of a natural nitrite source manufactured through ACP treatment can prospectively achieve suitable curing efficiency while simultaneously suppressing nitrosamine formation.

Evaluating the Potential of Vegetable Powders as Nitrite Replacements in Cured Pork Sausages: Effects of Different Processing Methods to Produce Chinese Cabbage and Radish Powders

This study investigated the potential of Chinese cabbage and radish powders as natural sources of nitrite in ground pork sausages. Four vegetable powders from Chinese cabbage and radish, depending on the processing method, were prepared for evaluation: filtered Chinese cabbage juice powder (FCJP), crushed Chinese cabbage powder (CCP), filtered radish juice powder (FRJP), and crushed radish powder (CRP). Both FCJP and FRJP from filtered juice of Chinese cabbages and radishes had higher total soluble solids and water soluble index compared to CCP and CRP from crushed Chinese cabbages and radishes. Additionally, FRJP and CRP showed a higher nitrate content than CCP and FCJP. The evaluation of vegetable powders against products containing sodium nitrite (control) or commercial vegetable powder in ground pork sausages showed that the use of FRJP and CRP resulted in similar levels of CIE a* compared to the control, whereas those cured with FCJP or CCP resulted in lower CIE a* values. However, regardless of the type and processing method of vegetables, all sausages treated with vegetable powders were similar in terms of cured pigment, total pigment, curing efficiency, and lipid oxidation compared with the control. Although lower hardness was observed in sausages treated with FRJP, no other treatments affected textural attributes. These results indicate that FRJP and CRP have great potential as natural curing agents for replacing nitrite in cured sausages. The use of powders obtained from filtered juices may provide extended utility as vegetable-based curing methods for other meat products.

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.

Emulsified and Nanoemulsified Essential Oils in the Control of Clostridium botulinum and Clostridium sporogenes in Mortadella

Clostridium botulinum is a foodborne pathogen responsible for severe neuroparalytic disease associated with the ingestion of pre-formed toxin in food, with processed meats and canned foods being the most affected. Control of this pathogen in meat products is carried out using the preservative sodium nitrite (NaNO2), which in food, under certain conditions, such as thermal processing and storage, can form carcinogenic compounds. Therefore, the objective was to use nanoemulsified essential oils (EOs) as natural antimicrobial agents, with the aim of reducing the dose of NaNO2 applied in mortadella. The antimicrobial activity of nanoemulsions prepared with mixtures of EOs of garlic, clove, pink pepper, and black pepper was evaluated on endospores and vegetative cells of C. botulinum and Clostridium sporogenes (surrogate model) inoculated in mortadella prepared with 50 parts per million NaNO2. The effects on the technological (pH, water activity, and color) and sensory characteristics of the product were also evaluated. The combinations of EOs and their nanoemulsions showed sporicidal effects on the endospores of both tested microorganisms, with no counts observed from the 10th day of analysis. Furthermore, bacteriostatic effects on the studied microorganisms were observed. Regarding the technological and sensorial characteristics of the product, the addition of the combined EOs had a negative impact on the color of the mortadella and on the flavor/aroma. Despite the strong commercial appeal of adding natural preservatives to foods, the effects on flavor and color must be considered. Given the importance of controlling C. botulinum in this type of product, as well as the reduction in the amount of NaNO2 used, this combination of EOs represents a promising antimicrobial alternative to this preservative, encouraging further research in this direction.

Effects of myofibril-palatinose conjugate as a phosphate substitute on meat emulsion quality

The objective of this study was to investigate a replacement for phosphate in meat products. Protein structural modification was employed in this study, and grafted myofibrillar protein (MP) with palatinose was added to meat emulsion without phosphate. Here, 0.15% of sodium polyphosphate (SPP) was replaced by the same (0.15%) concentration and double (0.3%) the concentration of grafted MP. Although the thermal stability was decreased, the addition of transglutaminase could increase stability. The rheological properties and pH also increased with the addition of grafted MP and transglutaminase. The addition of grafted protein could be perceived by the naked eye by observing a color difference before cooking, but it was not easy to detect after cooking. The cooking loss, emulsion stability, water holding capacity, lipid oxidation, and textural properties improved with the addition of grafted MP. However, the excessive addition of grafted MP and transglutaminase was not recommended to produce a high quality of phosphate replaced meat emulsion, and 0.15% was identified as a suitable addition ratio of grafted MP.

A Comprehensive Review of Cured Meat Products in the Irish Market: Opportunities for Reformulation and Processing

Cured meat products constitute one of the meat categories commonly consumed in Ireland and has been part of the Irish cuisine and diet for many years. Ham, gammon, and bacon are some of the products that involve curing as part of the traditional processing methods. Common among these products are high levels of salt and the addition of nitrites. These products undergo processing treatments to create variety, preserve shelf-life, and develop their unique quality and safety characteristics. However, consumers are becoming more conscious of the level of processing involved in these products, and the effects of some components and ingredients might be perceived as unhealthy. Meat product developers have been exploring ways to reduce the amount of ingredients such as salt, saturated fat, and chemical preservatives (e.g., nitrites), which are linked to health concerns. This is a challenging task as these ingredients play an important techno-functional role in the products' quality, safety, and identity. While innovative processing techniques are being introduced and progress has been made in reformulation and packaging technologies, much is still unknown, especially regarding the applicability of many of the proposed interventions to a wide range of meat products and their sustainability at the industrial scale.

Effects of Natural Extract Mixtures on the Quality Characteristics of Sausages during Refrigerated Storage

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.

Transcriptomic Responses to Nitrite Degradation by Limosilactobacillus fermentum RC4 and Effect of ndh Gene Overexpression on Nitrite Degradation

The excessive nitrite residue may increase cell damage and cancer risk. Limosilactobacillu fermentum RC4 exhibited excellent nitrite degradation ability. Herein, the molecular mechanism of nitrite degradation by L. fermentum RC4 was studied by integrating scanning electron microscopy analysis, transcriptomics, and gene overexpression. The results demonstrated that the gene profile of RC4 cultured in MRS broth with 0, 100, and 300 mg/L NaNO2 varied considerably; RC4 responded to nitrite degradation by regulating pyruvate metabolism, energy synthesis, nitrite metabolism, redox equilibrium, protein protection, and signaling. High nitrite concentrations affected the morphology of RC4 with a longer phenotype, rough and wrinkle cell and reduced cell surface hydrophobicity. Moreover, an up-regulated expression of gene ndh encoding NADH dehydrogenase, which provides electrons for nitrite reduction by catalyzing NADH, was identified when RC4 was exposed to nitrite. Overexpression of ndh in RC4 increased the nitrite degradation rate by 2-9.5% in MRS broth with 100 mg/L NaNO2. Thus, the findings of this study could be helpful for the application of L. fermentum to reduce nitrite residues and improve food safety in fermented food products.

Novel Approaches to Improve Meat Products' Healthy Characteristics: A Review on Lipids, Salts, and Nitrites

Meat products are a staple of many diets around the world, but they have been subject to criticism due to their potential negative impact on human health. In recent years, there has been a growing interest in developing novel approaches to improve the healthy characteristics of meat products, with a particular focus on reducing the levels of harmful salts, lipids, and nitrites. This review aims to provide an overview of the latest research on the various methods being developed to address these issues, including the use of alternative salts, lipid-reducing techniques, and natural nitrite alternatives. By exploring these innovative approaches, we can gain a better understanding of the potential for improving the nutritional value of meat products, while also meeting the demands of consumers who are increasingly concerned about their health and well-being.

Novel strategies for controlling nitrite content in prepared dishes: Current status, potential benefits, limitations and future challenges

Sodium nitrite is commonly used as a multifunctional curing ingredient in the processing of prepared dishes, especially meat products, to impart unique color, flavor and to prolong the shelf life of such products. However, the use of sodium nitrite in the meat industry has been controversial due to potential health risks. Finding suitable substitutes for sodium nitrite and controlling nitrite residue have been a major challenge faced by the meat processing industry. This paper summarizes possible factors affecting the variation of nitrite content in the processing of prepared dishes. New strategies for controlling nitrite residues in meat dishes, including natural pre-converted nitrite, plant extracts, irradiation, non-thermal plasma and high hydrostatic pressure (HHP), are discussed in detail. The advantages and limitations of these strategies are also summarized. Raw materials, cooking techniques, packaging methods, and storage conditions all affect the content of nitrite in the prepared dishes. The use of vegetable pre-conversion nitrite and the addition of plant extracts can help reduce nitrite residues in meat products and meet the consumer demand for clean labeled meat products. Atmospheric pressure plasma, as a non-thermal pasteurization and curing process, is a promising meat processing technology. HHP has good bactericidal effect and is suitable for hurdle technology to limit the amount of sodium nitrite added. This review is intended to provide insights for the control of nitrite in the modern production of prepared dishes.

Effects of grafted myofibrillar protein as a phosphate replacer in brined pork loin

For the development of healthier meat products, the grafted myofibrillar protein was evaluated as an ingredient that can substitute phosphate in brined loin. Individual brine solutions, consisting of salt (negative control, NP), salt + sodium tripolyphosphate (positive control, PC), salt + myofibrillar protein without grafting (MP), salt + myofibrillar protein grafted at high concentration (GMP-H), and salt + myofibrillar protein grafted at low concentration (GMP-L), were added to the pork loin by 40% of their weight. Differential scanning calorimetry demonstrated that MP and GMP-H lowered the thermal energy for the transition of myosin and actin, thereby improving the thermal stability of pork loin and increasing protein solubility. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that thicker protein bands appeared in MP and GMP-H samples while exhibiting increased pH values, moisture content, water holding capacity, and processing yield. Accordingly, the shear force of MP and GMP-H decreased. Lipid oxidation of pork loin was increased in MP, whereas it decreased in GMP-H. Thus, GMP-L is a potential substitute for phosphate since it improves physicochemical properties and prevents the lipid oxidation of pork loin.

The Influence of the Apple Vinegar Marination Process on the Technological, Microbiological and Sensory Quality of Organic Smoked Pork Hams

The effect of marinating pork hams in apple vinegar on the technological, microbiological, and sensory quality was verified. Three variants of pork hams were produced: S1-ham with curing salt, without apple vinegar; S2-ham with curing salt and 5% apple vinegar; S3-ham with salt and 5% apple vinegar. The tests were carried out immediately after production, after 7 and 14 days of storage. The products did not differ significantly in their chemical composition, salt content, fatty acid composition, and water activity (p > 0.05). During storage, a significant increase in the cholesterol content was observed (64.88-72.38 mg/100 g of the product). The lowest levels of nitrites and nitrates were recorded for treatment S3 (<0.10 and 4.73 mg/kg of product, respectively). The samples with the addition of apple vinegar (S2 and S3) were characterized by a lower pH value, higher oxidation-reduction potential, and TBARS (thiobarbituric acid reactive substances). Hams S3 were significantly brighter (L* 68.89) and less red (a* 12.98). All of the tested pork hams were characterized by very good microbiological quality (total number of microorganisms, number of lactic acid bacteria, number of acetic bacteria, number or presence of pathogenic bacteria). Significantly the lowest TVC (total viable counts) was found in the ham S3 (2.29 log CFU/g after 14 days). The S3 hams during storage were characterized by greater juiciness (6.94 c.u.) and overall quality (7.88 c.u.), but a lower intensity of smell and taste than the cured ham (S1). To sum up, it is possible to produce pork hams without the addition of curing salt, using natural apple vinegar as a marinade. Apple vinegar has a positive effect on the storage stability of the products, without losing their sensory properties.

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.

Effects of Nitrite and Phosphate Replacements for Clean-Label Ground Pork Products

We investigated the effects of different phosphate replacements on the quality of ground pork products cured with sodium nitrite or radish powder to determine their potential for achieving clean-label pork products. The experimental design was a 2×5 factorial design. For this purpose, the ground meat mixture was assigned into two groups, depending on nitrite source. Each group was mixed with 0.01% sodium nitrite or 0.4% radish powder together with 0.04% starter culture, and then processed depending on phosphate replacement [with or without 0.5% sodium tripolyphosphate; STPP (+), STPP (-), 0.5% oyster shell calcium (OSC), 0.5% citrus fiber (CF), or 0.5% dried plum powder (DPP)]. All samples were cooked, cooled, and stored until analysis within two days. The nitrite source had no effect on all dependent variables of ground pork products. However, in phosphate replacement treatments, the STPP (+) and OSC treatments had a higher cooking yield than the STPP (-), CF, or DPP treatments. OSC treatment was more effective for lowering total fluid separation compared to STPP (-), CF, or DPP treatments, but had a higher percentage than STPP (+). The STPP (+) treatment did not differ from the OSC or CF treatments for CIE L* and CIE a*. Moreover, no differences were observed in nitrosyl hemochrome content, lipid oxidation, hardness, gumminess, and chewiness between the OSC and STPP (+) treatments. In conclusion, among the phosphate replacements, OSC addition was the most suitable to provide clean-label pork products cured with radish powder as a synthetic nitrite replacer.

Improvement of structural, physicochemical, and rheological properties of porcine myofibrillar proteins by high-intensity ultrasound treatment for application as Pickering stabilizers

This study aimed to evaluate the potential of time-dependent (0, 15, 30, 60, 120 min) treatment of porcine-derived myofibrillar proteins (MPs) with high-intensity ultrasound (HIU) for utilizing them as a Pickering stabilizer and decipher the underlying mechanism by which HIU treatment increases the emulsification and dispersion stability of MPs. To accomplish this, we analyzed the structural, physicochemical, and rheological properties of the HIU-treated MPs. Myosin heavy chain and actin were observed to be denatured, and the particle size of MPs decreased from 3,342.7 nm for the control group to 153.9 nm for 120 min HIU-treated MPs. Fourier-transformed infrared spectroscopy and circular dichroism spectroscopy confirmed that as the HIU treatment time increased, α-helical content increased, and β-sheet decreased, indicating that the protein secondary/tertiary structure was modified. In addition, the turbidity, apparent viscosity, and viscoelastic properties of the HIU-treated MP solution were decreased compared to the control, while the surface hydrophobicity was significantly increased. Analyses of the emulsification properties of the Pickering emulsions prepared using time-dependent HIU-treated MPs revealed that the emulsion activity index and emulsion stability index of HIU-treated MP were improved. Confocal laser scanning microscopy images indicated that small spherical droplets adsorbed with MPs were formed by HIU treatment and that dispersion stabilities were improved because the Turbiscan stability index of the HIU-treated group was lower than that of the control group. These findings could be used as supporting data for the utilizing porcine-derived MPs, which have been treated with HIU for appropriate time periods, as Pickering stabilizers.

Effects of Fermented Garlic Extract Containing Nitric Oxide Metabolites on Blood Flow in Healthy Participants: A Randomized Controlled Trial

Aged or fermented garlic extract (FGE) is a natural remedy that improves vascular function through increasing vascular nitric oxide (NO) bioavailability. This is because nitrite (NO2-), a NO metabolite, can be produced through bioconversion with macrobacteria during the fermentation of foods like garlic. We aimed to evaluate the effects of NO2- in FGE on blood flow (BF), blood pressure (BP), velocity of the common carotid artery (CCA) and internal carotid artery (ICA), regional cerebral BF (rCBF), and peripheral BF (PBF). The study was divided into two parts: (1) Thirty healthy adults were divided into FGE and placebo groups to compare BP and velocity of the CCA and ICA; and (2) Twenty-eight healthy adults were divided into FGE and placebo groups to compare rCBF and PBF and determine changes before/after ingestion. Significant changes were noted in BP and the velocity of both CCA 30-60 min after FGE ingestion. FGE ingestion resulted in significant increases in rCBF and increases in body surface temperature through alterations in PBF. No detectable clinical side effects were noted. Overall, oral administration of NO2- containing FGE demonstrated acute positive effects in upregulating BF, including the CCA, BP, rCBF, and PBF. Follow-up studies with larger sample sizes and long-term ingestion may be needed.

Effects of Lemon Extract Powder and Vinegar Powder on the Quality Properties of Naturally Cured Sausages with White Kimchi Powder

This study investigated the effects of lemon extract powder and vinegar powder on the physicochemical and microbiological characteristics of pork sausages naturally cured using white kimchi powder during storage for 30 days. Six batches were included: control (0.01% sodium nitrite and 0.05% sodium ascorbate); treatment 1 (0.3% white kimchi powder and 0.5% lemon extract powder); treatment 2 (0.3% white kimchi powder and 1.0% lemon extract powder); treatment 3 (0.3% white kimchi powder and 0.5% vinegar powder); treatment 4 (0.3% white kimchi powder and 1.0% vinegar powder); and treatment 5 (0.3% white kimchi powder, 0.5% lemon extract powder, and 0.5% vinegar powder). Treatment 2 had significantly lower pH values and higher cooking loss than the other batches (p<0.05). Treatments 1, 2, and 5 had similar (p>0.05) CIE a* as the control, while treatments 3 and 4 showed significantly lower values (p<0.05). The residual nitrite content in naturally cured products was lower than the control (p<0.05), while treatments 1 and 2 showed significantly higher nitrosyl hemochrome content and curing efficiency (p<0.05). TBARS values were similar for all treatments and the control (p>0.05). Treatments 1 and 2 showed significantly reduced aerobic plate counts (APC; p<0.05) than the control and other treatments. However, across all batches, TBARS values and APC significantly increased during storage (p<0.05). Our results suggest that lemon extract powder, rather than vinegar powder, may offer a promising alternative for supplementing the functions of nitrite in naturally cured sausages.

Natural Extracts as Inhibitors of Microorganisms and Lipid Oxidation in Emulsion Sausage during Storage

Food additives are required to maintain the freshness and quality of foods, particularly meats. However, chemical additives may not be preferred by consumers, and natural materials with antimicrobial and antioxidant effects may be used as replacements for common chemical additives. Accordingly, in this study, we compared the antimicrobial and antioxidant activities of natural compounds extracted with ethanol and hot water, and emulsion sausage prepared with natural ethanol extracts was analyzed for pH, color, thiobarbituric acid reactive substances (TBARS), and Clostridium perfringens growth during storage. The antimicrobial activities of 49 natural extract candidates against Listeria monocytogenes, C. perfringens, Salmonella spp., and Escherichia coli were analyzed, and six natural materials with excellent antibacterial activities, i.e., Elaeagnus umbellata Thunb. f. nakaiana (Araki) H. Ohba, Punica granatum L., Ecklonia cava, Nelumbo nucifera Gaertner, and Schisandra chinensis (Turcz.) Baill., and Rubus coreanus Miq. were evaluated to determine their total polyphenol contents and DPPH radical scavenging activities. The total polyphenol contents of ethanol extracts were higher than those of hot water extracts, whereas DPPH radical scavenging activity was found to be higher in hot water extracts. The TBARS values of emulsion sausages were significantly increased as storage time increased, and the TBARS values of emulsion sausages prepared with natural extracts were lower than those of control sausages. Natural extract-treated emulsion sausages showed a 99% reduction in bacterial contents compared with untreated sausages on day 2, with greater than 99.9% reduction after day 3. Thus, these results demonstrated that natural extracts could have applications as natural preservatives in meat products.

Use of Green Tea Extract and Rosemary Extract in Naturally Cured Pork Sausages with White Kimchi Powder

The impact of green tea extract powder and rosemary extract powder, alone or in combination, on the quality characteristics of naturally cured pork sausages produced with white kimchi powder as a nitrate source was evaluated. Ground pork sausages were assigned to one of seven treatments: control (0.01% sodium nitrite and 0.05% sodium ascorbate), treatment 1 (0.3% white kimchi powder and 0.05% green tea extract powder), treatment 2 (0.3% white kimchi powder and 0.1% green tea extract powder), treatment 3 (0.3% white kimchi powder and 0.05% rosemary extract powder), treatment 4 (0.3% white kimchi powder and 0.1% rosemary extract powder), treatment 5 (0.3% white kimchi powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder), and treatment 6 (0.3% celery juice powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder). Naturally cured products had lower (p<0.05) cooking yield and residual nitrite content than control sausages. However, compared to the control, naturally cured products with white kimchi powder (treatments 1 to 5) showed similar the pH, oxidation-reduction potential, CIE L* values, CIE a* values, nitrosyl hemochrome content, total pigment content, and curing efficiency to the control. When the amount of green tea extract powder or rosemary extract powder was increased to 0.1% (treatments 2 and 4), lipid oxidation was reduced (p<0.05). These results indicate that green tea extract powder, rosemary extract powder, and white kimchi powder may provide an effective solution to replace synthetic nitrite and ascorbate used in traditionally cured products.

Application of Natural Preservatives for Meat and Meat Products against Food-Borne Pathogens and Spoilage Bacteria: A Review

Meat and meat products are excellent sources of nutrients for humans; however, they also provide a favorable environment for microbial growth. To prevent the microbiological contamination of livestock foods, synthetic preservatives, including nitrites, nitrates, and sorbates, have been widely used in the food industry due to their low cost and strong antibacterial activity. Use of synthetic chemical preservatives is recently being considered by customers due to concerns related to negative health issues. Therefore, the demand for natural substances as food preservatives has increased with the use of plant-derived and animal-derived products, and microbial metabolites. These natural preservatives inhibit the growth of spoilage microorganisms or food-borne pathogens by increasing the permeability of microbial cell membranes, interruption of protein synthesis, and cell metabolism. Natural preservatives can extend the shelf-life and inhibit the growth of microorganisms. However, they can also influence food sensory properties, including the flavor, taste, color, texture, and acceptability of food. To increase the applicability of natural preservatives, a number of strategies, including combinations of different preservatives or food preservation methods, such as active packaging systems and encapsulation, have been explored. This review summarizes the current applications of natural preservatives for meat and meat products.

Effect on health from consumption of meat and meat products

The aim of this study was to investigate the effects of dietary sodium nitrite and meat on human health. Sodium nitrite in processed meat is known to be one of the main precursors of carcinogens, such as N-nitroso compounds. However, we previously found that processed meat is not the primary source of sodium nitrite; nitrate or the conversion of nitrate in vegetables are contribute to generate more than 70% Sodium nitrite or nitrate containing compounds in body. Although the heavy consumption of meat is likely to cause various diseases, meat intake is not the only cause of colorectal cancer. Our review indicates that sodium nitrite derived from foods and endogenous nitric oxide may exhibit positive effects on human health, such as preventing cardiovascular disease or improving reproductive function. Therefore, further epidemiological studies considering various factors, such as cigarette consumption, alcohol consumption, stress index, salt intake, and genetic factors, are required to reliably elucidate the effects of dietary sodium nitrite and meat on the incidence of diseases, such as colorectal cancer.

Clean Label Alternatives in Meat Products

Food authorities have not yet provided a definition for the term "clean label". However, food producers and consumers frequently use this terminology for food products with few and recognisable ingredients. The meat industry faces important challenges in the development of clean-label meat products, as these contain an important number of functional additives. Nitrites are an essential additive that acts as an antimicrobial and antioxidant in several meat products, making it difficult to find a clean-label alternative with all functionalities. Another important additive not complying with the clean-label requirements are phosphates. Phosphates are essential for the correct development of texture and sensory properties in several meat products. In this review, we address the potential clean-label alternatives to the most common additives in meat products, including antimicrobials, antioxidants, texturisers and colours. Some novel technologies applied for the development of clean label meat products are also covered.