Meat Spoilage: A Critical Review of a Neglected Alteration Due to Ropy Slime Producing Bacteria

Fortification of cassava starch edible films with Litsea cubeba essential oil for chicken meat preservation

Chicken meat is highly perishable and mainly preserved by plastic packaging materials, whereas their widely used have increased environmental burden and threatened human health. Bioactive packaging materials fabricated by biopolymers are promising alternatives for meat preservation. Herein, cassava starch (CS)/sodium carboxymethyl cellulose (CMC) edible films fortified with Litsea cubeba essential oil (LC-EO) were fabricated and characterized. Results showed the textural, mechanical and barrier properties of the CS/CMC edible films were significantly improved after incorporating with LC-EO. Moreover, the composite edible films exhibited potent antibacterial properties, biodegradability, hydrophobicity, and thermal stability. Whereas the water solubility and moisture content was reduced up to 29.68 % and 24.37 %, respectively. The release behavior of LC-EO suggested the suitability of the composite edible films for acidic foods. Comparing with the control group, the pH values of the meat samples packaged with CS/CMC/LCEO-4 mg/mL edible films maintained at around 6.7, and weight loss rate was 15 %. The color and texture changes, and the lipid oxidation of the meat samples with CS/CMC/LCEO-4 mg/mL packaging were also markedly delayed. The microbial growth was retarded at 6.35 log CFU/g after storage for 10 days. These findings suggested the CS/CMC/LCEO-4 mg/mL edible films had great potential for chicken meat preservation.

Pomegranate Peel and Olive Leaf Extracts to Optimize the Preservation of Fresh Meat: Natural Food Additives to Extend Shelf-Life

Quality and safety are one of the main concerns of the European Union in food preservation. Using chemical additives extends the shelf-life of fresh foods but raises consumer's concerns about the potential long-term carcinogenic effects. Using natural substances derived from agro-industrial by-products, which have significant antimicrobial and antioxidant activities, could extend the shelf-life of fresh foods such as meat. Furthermore, they can provide nutritional improvements without modifying organoleptic properties. This study analyzes the antimicrobial activity of pomegranate peel extract (PPE) and the antioxidant activity of olive leaf extract (OLE), added at concentrations of 10 mg g-1 and 0.25 mg g-1, respectively, to minced poultry and rabbit meat. PPE exhibited in vitro antimicrobial activity against foodborne pathogens starting at 10 mg/well. PPE and OLE determined a reduction in colony count over a storage period of 6 days at 4 °C. Additionally, the combination of PPE and OLE showed antioxidant effects, preserving lipid oxidation and maintaining pH levels. The obtained results demonstrate that PPE and OLE can be recommended as food additives to preserve the quality and extend the shelf-life of meat products.

Novel Iminocoumarin-substituted Tetraphenylethylene-based Near-infrared Fluorescent Probe for Ratiometric Detection of F- and H2S

An iminocoumarin and tetraphenylethylene compound that exhibits aggregation-induced emission (AIE) and a significant Stokes shift (Δλ = 135 nm) in THF was created via the Knoevenagel condensation method. TPICBT could also be used as a ratiometric near-infrared fluorescent probe for the naked color identification of F- and H2S. It showed a large red shift (˃ 90 nm), good selectivity, and anti-interference. Test strip detection and cell imaging had both been accomplished using the probe. In addition, the probe could conveniently detect H2S produced during food spoilage without laboratory instruments.

Leuconostoc gelidum Is the Major Species Responsible for the Spoilage of Cooked Sausage Packaged in a Modified Atmosphere, and Hop Extract Is the Best Inhibitor Tested

Cooked sausages packaged in a modified atmosphere (MAP: 20% CO2, 70% N2, <0.2% O2) with evident yellow stains were analyzed. The aims of this work were to study the microbial cause of the spoilage and to evaluate different antimicrobial compounds to prevent it. Leuconostoc gelidum was identified as the primary cause of the yellow coating in spoiled cooked sausage, as confirmed by its intentional inoculation on slices of unspoiled sausage. Leuconostoc gelidum was the main bacteria responsible for the yellow coating in spoiled cooked sausage, as confirmed by its intentional inoculation on slices of unspoiled sausage. The yellow color was also evident during growth in the model system containing cooked sausage extract, but the colonies on MRS agar appeared white, demonstrating that the food substrate stimulated the production of the yellow pigment. The spoilage was also characterized by different volatile compounds, including ketones, ethanol, acetic acid, and ethyl acetate, found in the spoiled cooked sausage packages. These compounds explained the activity of Leuc. gelidum because they are typical of heterofermentative LAB, cultivated either on food substrates or in artificial broths. Leuc. gelidum also produced slight swelling in the spoiled packages. The efficacy of different antimicrobials was assessed in model systems composed of cooked sausage extract with the antimicrobials added at food product concentrations. The data showed that sodium lactate, sodium acetate, and a combination of sodium lactate and sodium diacetate could only slow the growth of the spoiler-they could not stop it from occurring. Conversely, hop extract inhibited Leuc. gelidum, showing a minimal inhibitory concentration (MIC) of approximately 0.008 mg CAE/mL in synthetic broth and 4 mg CAE/kg in cooked sausage slices. Adding hop extract at the MIC did not allow Leuc. gelidum growth and did not change the sensorial characteristics of the cooked sausages. To our knowledge, this is the first report of the antimicrobial activities of hop extracts against Leuc. gelidum either in vitro or in vivo.

Beyond Conventional Meat Preservation: Saddling the Control of Bacteriocin and Lactic Acid Bacteria for Clean Label and Functional Meat Products

Advancements in food science and technology have paved the way for the development of natural antimicrobial compounds to ensure the safety and quality of meat and meat products. Among these compounds, bacteriocin produced by lactic acid bacteria has gained considerable scientific attention for its ability to preserve the healthy properties of meat while preventing spoilage. This natural preservative is seen as a pioneering tool and a potent alternative to chemical preservatives and heat treatment, which can have harmful effects on the nutritional and sensory qualities of meat. Bacteriocin produced by lactic acid bacteria can be used in various forms, including as starter/protective cultures for fermented meats, purified or partially purified forms, loaded in active films/coatings, or established in encapsulate systems. This review delves into the downstream purification schemes of LAB bacteriocin, the elucidation of their characteristics, and their modes of action. Additionally, the application of LAB bacteriocins in meat and meat products is examined in detail. Overall, the use of LAB bacteriocins holds immense potential to inspire innovation in the meat industry, reducing the dependence on harmful chemical additives and minimizing the adverse effects of heat treatment on nutritional and sensory qualities. This review provides a comprehensive understanding of the potential of bacteriocin produced by lactic acid bacteria as a natural and effective meat preservative.

Relationships of quality indices with wooden breast myopathy severity in chicken breast meat under refrigerated storage

1. This study investigated the relationships of quality indices with the severity of wooden breast (WB) myopathy in chicken breast meat under refrigerated storage. The physicochemical properties, water-holding capacity (WHC), microbial quality and fatty acid profiles of normal chicken breast meat samples (NOR samples, n = 63), moderate WB (MWB, n = 63) myopathy and severe WB (SWB, n = 63) myopathy (MWB and SWB samples, respectively) were evaluated immediately after sampling and after 4 and 8 d of refrigerated storage at 4°C.2. Total collagen, fat, saturated and monounsaturated fatty acid contents, redness and pH of the SWB and MWB samples were higher than the NOR samples. The SWB samples that were stored for 8 d had poor WHC, total viable counts (TVC) of higher than 7.0log colony-forming units, total volatile basic nitrogen (TVB-N) content of greater than 15 mg/100 g and a thiobarbituric acid - reactive substance level of higher than 1 mg/kg malondialdehyde.3. No significant difference was observed in the TVB-N content and TVC of the MWB and NOR samples during storage. Polyunsaturated fatty acid content was lower in the SWB and MWB samples than in the NOR samples. The SWB samples were tougher than the MWB and NOR samples after 8 d of refrigeration.4. In conclusion, the quality of chicken breast meat with SWB myopathy degraded considerably over time; thus, such meat should not be subjected to extended refrigeration for storage.

Carnobacterium maltaromaticum as bioprotective culture against spoilage bacteria in ground meat and cooked ham

This study assessed the bioprotective effect of Carnobacterium maltaromaticum (CM) against Pseudomonas fluorescens (PF) and Brochothrix thermosphacta (BT) in ground beef and sliced cooked ham stored in high- and low-oxygen-modified atmospheres (66/4/30% O2/N2/CO2 and 70/30% N2/CO2, respectively). Both meat products were inoculated with CM, PF, and BT individually or in combination and stored for 7 days (3 days at 4 °C + 4 days at 8 °C) for ground beef and 28 days (10 days at 4 °C + 18 days at 8 °C) for sliced cooked ham. Each food matrix was assigned to 6 treatments: NC (no bacterial inoculation, representing the indigenous bacteria of meat), CM, BT, PF, CM + BT, and CM + PF. Bacterial growth, pH, instrumental color, and headspace gas composition were assessed during storage. CM counts remained stable from inoculation and throughout the shelf-life. CM reduced the population of inoculated and indigenous spoilage bacteria, including BT, PF, and enterobacteria, and showed a negligible impact on the physicochemical quality parameters of the products. Furthermore, upon simulating the shelf-life of ground beef and cooked ham, a remarkable extension could be observed with CM. Therefore, CM could be exploited as a biopreservative in meat products to enhance quality and shelf-life.

Volatile Compound Markers in Beef Irradiated with Accelerated Electrons

This study focuses on the behavior of volatile organic compounds in beef after irradiation with 1 MeV accelerated electrons with doses ranging from 0.25 kGy to 5 kGy to find reliable dose-dependent markers that could be used for establishing an effective dose range for beef irradiation. GC/MS analysis revealed that immediately after irradiation, the chemical yield and accumulation rate of lipid oxidation-derived aldehydes was higher than that of protein oxidation-derived aldehydes. The nonlinear dose-dependent relationship of the concentration of volatile organic compounds was explained using a mathematical model based on the simultaneous occurrence of two competing processes: decomposition of volatile compounds due to direct and indirect action of accelerated electrons, and accumulation of volatile compounds due to decomposition of other compounds and biomacromolecules. A four-day monitoring of the beef samples stored at 4 °C showed that lipid oxidation-derived aldehydes, protein oxidation-derived aldehydes and alkanes as well as alcohol ethanol as an indicator of bacterial activity were dose-dependent markers of biochemical processes occurring in the irradiated beef samples during storage: oxidative processes during direct and indirect action of irradiation, oxidation due to the action of reactive oxygen species, which are always present in the product during storage, and microbial-enzymatic processes. According to the mathematical model of the change in the concentrations of lipid oxidation-derived aldehydes over time in the beef samples irradiated with different doses, it was found that doses ranging from 0.25 kGy to 1 kGy proved to be most effective for beef irradiation with accelerated electrons, since this dose range decreases the bacterial content without considerable irreversible changes in chemical composition of chilled beef during storage.

Street Pork Vendors' Hygiene and Safety Practices and Their Determinants in the Cape Metropole District, South Africa

South Africa's rapid urbanization and high unemployment rates pushed people into street food vending as an alternative source of livelihood. Hygiene and food safety have become a concern under these circumstances owing to foodborne illnesses and associated deaths. A survey tool with 38 structured questions was administered to 172 to assess pork vendors' hygiene and safety practices and identify their determinants in five low-income high-density suburbs of the Cape Metropole District, South Africa. Overall, vendors washed their hands before and after handling meat (66% of respondents) and cleaned the working area daily (51%), pork storage area daily (60%), and utensils and equipment before and after use (36%) with most of them using detergents as the main cleaning agent (70%). A quarter of the interviewed vendors experienced meat spoilage during storage, and 80% had no training in hygiene and safe food handling. The marginal effects of logistic regression findings showed that vending income increased the vendor's probability to wash hands, and clean vending stalls, storage areas, utensils, and equipment. The likelihood of vendors cleaning pork storage areas, utensils, and equipment increased with the increase in female participants. The likelihood of hand washing and vending stall cleaning increased by 1% for each extra year of schooling. Strategies aimed at improving meat hygiene and safety practices of vendors in the surveyed areas should target vulnerable groups, especially less educated females depending solely on vending income.

Effect of dietary fat on proximal composition, sensorial analysis and shelf life of a traditional Spanish cooked pork product "Lomo de Sajonia" from Iberian pork

This study aims to evaluate the effect of different dietary fat sources on the quality of a Spanish-cooked meat product Lomo de Sajonia (LSA) and its shelf-life. Forty loins were selected from Iberian pigs fed four dietary treatments containing pork fat (G-1), Greedy-Grass Olive® (GGO) (enriched oleic-acid oil) (G-2), G-2 and high oleic sunflower (G-3), and G-3 plus a mixture of commercial organic acids (Bioll®) (G-4). Loins were manufactured to obtain LSA, and the quality and sensorial attributes were assessed. The shelf life was established according to microbial count and sensorial analysis, which was packed in a modified atmosphere and stored under retail conditions. All meat quality parameters of LSA remained stable in all groups, except fat content and overall liking, which showed the highest values for G-2 LSA. Regarding the shelf life, sensorial attributes remained acceptable in all groups during storage time, while a delay in microbial growth was recorded for the LSA of G-3. According to the results, including GGO in Iberian pig diets could enhance LSA traits, possibly linked to increased assimilation compared with conventional fat sources. However, adding organic acids to the diet did not have the expected effect on improving the shelf life of the LSA.

Nisin and Organic Acid Salts Improved the Microbial Quality, Extended the Shelf Life, and Maintained the Sensory Attributes of Semidry Beef Luncheon Marketed at Adverse (35-40 °C) Ambient Summer Temperatures

Semidry beef luncheon may undergo deteriorative changes during storage at ambient temperatures in tropical and subtropical regions including Egypt. This study was conducted in a meat plant in Egypt with the aim of overcoming the economic losses from the returns of spoiled unsold beef luncheon displayed in grocery stores at adverse summer temperatures of 37 °C or more. Ten approaches were applied using different preservatives, comprising sodium nitrite, nisin, potassium sorbate, and organic acid salts (a combination of sodium lactate, sodium acetate, and sodium diacetate). In addition, the product was cooked at different temperatures and was stored for 21 days at 37 °C, during which time the shelf life, microbial quality, pH, and sensory attributes were investigated. By Day 21 of storage, the luncheon contained 50 mg/kg sodium nitrite, 25 mg/kg nisin, and 1000 mg/kg organic acid salts and, when cooked at a final core temperature of 92 °C, exhibited reductions in aerobic plate count, anaerobic plate count, lactic acid bacterial count, and mold and yeast counts by 4.32, 3.54, 3.47, and 1.89 log10 CFU/g, respectively, when compared with the control. The sensory attributes and pH were also maintained in the final products of such treatment, with no product return and the avoidance of economic loss. This study presents a novel approach for solving the major problem of the deteriorative changes that occur in semidry luncheon sausage and similar meat products which require rejection with a huge economic loss, especially in tropical and semitropical areas of the world that have similar problems of high climatic temperatures and a low availability of energy or technological resources.

Influence of Hempseed Meal on Fresh Goat Meat Characteristics Stored in Vacuum Packaging

The objective of this study was to determine the influence of hempseed meal (HSM) on goat meat characteristics. Goats (N = 10/treatment) were allocated to a diet concentration (0, 10, 20, or 30%) of HSM, fed for 60 days, and harvested. Carcass measurements were collected after chilling, and subsequently fabricated into wholesale subprimals. From the subprimals of the shoulder and leg, steaks were cut 2.54 cm thick, vacuum packaged, and assigned to laboratory methods: cook yield, instrumental color, lipid oxidation, microbial spoilage, and instrumental tenderness. HSM did not alter (p > 0.05) carcass characteristics, microbial spoilage, cook loss, or the thiobarbituric acid reactive substance (TBARS). However, a decrease in objective tenderness measurements (p < 0.05) was observed with greater concentrations of HSM supplementation in the diet. Instrumental surface color values for lightness (L*) indicated that steaks became lighter and less red (a*) as storage time increased (p < 0.05). Results suggest that HSM and storage time do not alter some goat meat traits, but HSM or storage time separately may influence goat meat quality. HSM may be an effective feed ingredient that does not alter carcass quality or meat yield.

A novel chromophore reaction-based pyrrolopyrrole aza-BODIPY fluorescent probe for H2S detection and its application in food spoilage

In this work, we developed an aggregation-induced emission enhancement (AIEE) active and NIR emissive pyrrolopyrrole aza-BODIPY (PPAB) polymer (P1) for H₂S detection for the first time. P1 showed obvious colorimetric change from green to yellow-green and ratiometric fluorescence "turn on" phenomenon with 167 nm blue-shift (from dark red to bright green). The sensing mechanism revealed a novel chromophore reaction between imine in PPAB core and H₂S was involved, leading to less conjugated product. It exhibited distinct advantages of good selectivity, high sensitivity, and low detection limit of 0.66 μM. The potential applicability of P1 for H₂S detection in the real samples (tap water, lake water and milk) was demonstrated. In addition, the solid sensor prepared by loading P1 on the PMMA film was successfully realized the visual detection of gaseous H₂S gas produced from egg spoilage. Therefore, this work provides a promising approach based on novel sensing mechanism for monitoring H₂S in complicated biological systems and practical food samples.

Effect of high pressure processing and water activity on pressure resistant spoilage lactic acid bacteria (Latilactobacillus sakei) in a ready-to-eat meat emulsion model

The main use of High Pressure Processing (HPP) in food processing is microorganism inactivation, and studies demonstrated that the characteristics of matrix and microorganisms can interfere on it. As the behavior of lactic acid bacteria exposed to different water activity (a_w) levels in a meat product is still unclear, this study aimed to determine the effect of pressure, time, and a_w to inactivate Latilactobacillus sakei, a pressure resistant lactic acid bacteria (LAB) in a meat emulsion model through a response surface methodology. The meat emulsion model was designed with adjusted a_w (from 0.940 to 0.960) and was inoculated with a pressure resistant LAB and processed varying pressure (400-600 MPa) and time (180-480 s), following the Central Composite Rotational Design (CCRD). The inactivation of the microorganism ranged from 0.99 to 4.12 UFC/g depending on the applied condition. At studied conditions, according to the best fitting and most significant polynomial equation (R² of 89.73 %), in a meat emulsion model, a_w had no influenced on HPP inactivation on LAB (p > 0.05) and only pressure and holding time had significative impact on it. The results of experimental validation of the mathematical model were satisfactory, confirming the suitability of the model. The information obtained in the present study stands out the matrix, microorganism and process effects at HPP efficiency. The answers obtained support food processors in product development, process optimization and food waste reduction.

Antimicrobial and Antioxidant Edible Films and Coatings in the Shelf-Life Improvement of Chicken Meat

Meat deterioration during processing, distribution, and display can compromise the quality and safety of products, causing several undesirable changes and decreasing products' shelf-life, which has a negative impact on the industry and consumers. In recent years, studies have been carried out using decontamination techniques and new packaging methodologies to overcome deterioration problems, increase sustainability, and reduce waste. Edible films and coatings obtained from biopolymers such as polysaccharides, proteins, and lipids, combined with active compounds, can be an alternative approach. This article focused on recent studies that used alternative biodegradable polymeric matrices in conjunction with natural compounds with antioxidant/antimicrobial activity on chicken meat. Its impact on physicochemical, microbiological, and sensory characteristics was evident, as well as the effect on its shelf-life. In general, different combinations of active edible films or coatings had a positive effect on the chicken meat. Different studies reported that the main results were a decrease in microbial growth and pathogen survival, a slowdown in lipid oxidation evolution, and an improvement in sensory quality and shelf-life (an increase from 4 to 12 days).

Meat Irradiation: A Comprehensive Review of Its Impact on Food Quality and Safety

Food irradiation is a proven method commonly used for enhancing the safety and quality of meat. This technology effectively reduces the growth of microorganisms such as viruses, bacteria, and parasites. It also increases the lifespan and quality of products by delaying spoilage and reducing the growth of microorganisms. Irradiation does not affect the sensory characteristics of meats, including color, taste, and texture, as long as the appropriate dose is used. However, its influence on the chemical and nutritional aspects of meat is complex as it can alter amino acids, fatty acids, and vitamins as well as generate free radicals that cause lipid oxidation. Various factors, including irradiation dose, meat type, and storage conditions, influence the impact of these changes. Irradiation can also affect the physical properties of meat, such as tenderness, texture, and water-holding capacity, which is dose-dependent. While low irradiation doses potentially improve tenderness and texture, high doses negatively affect these properties by causing protein denaturation. This research also explores the regulatory and public perception aspects of food irradiation. Although irradiation is authorized and controlled in many countries, its application is controversial and raises concerns among consumers. Food irradiation is reliable for improving meat quality and safety but its implication on the chemical, physical, and nutritional properties of products must be considered when determining the appropriate dosage and usage. Therefore, more research is needed to better comprehend the long-term implications of irradiation on meat and address consumer concerns.

Preparation of lemon essential oil nanoemulsion and its effect on the microbial community of pork patties

The purpose of this study was to prepare an essential oil nanoemulsion and apply it to meat products to achieve antimicrobial effect. The nanoemulsion of lemon essential oil was produced by high power ultrasonication. The influences of ultrasonic power, ultrasonic time, and mass ratio of sodium caseinate to essential oil on the particle size were examined. The optimal conditions for preparing nanoemulsion were ultrasonic power 327 W, ultrasonic time 18 min, and sodium caseinate to essential oil mass ratio 4.23:1. Lower temperature was more conducive to the preservation of nanoemulsion. Compared to control and essential oil group, the nanoemulsion could decrease the total volatile basic nitrogen content and total bacterial colony in pork patties. When applied to pork patties, the nanoemulsion decreased the microbial diversity and inhibited the growth of a variety of microorganisms such as Bacillus, extending the storage time of pork patties. This study developed a novel and workable nanoemulsion for inhibiting bacteria of meat products.

A Review of Modern Methods for the Detection of Foodborne Pathogens

Despite the recent advances in food preservation techniques and food safety, significant disease outbreaks linked to foodborne pathogens such as bacteria, fungi, and viruses still occur worldwide indicating that these pathogens still constitute significant risks to public health. Although extensive reviews of methods for foodborne pathogens detection exist, most are skewed towards bacteria despite the increasing relevance of other pathogens such as viruses. Therefore, this review of foodborne pathogen detection methods is holistic, focusing on pathogenic bacteria, fungi, and viruses. This review has shown that culture-based methods allied with new approaches are beneficial for the detection of foodborne pathogens. The current application of immunoassay methods, especially for bacterial and fungal toxins detection in foods, are reviewed. The use and benefits of nucleic acid-based PCR methods and next-generation sequencing-based methods for bacterial, fungal, and viral pathogens' detection and their toxins in foods are also reviewed. This review has, therefore, shown that different modern methods exist for the detection of current and emerging foodborne bacterial, fungal, and viral pathogens. It provides further evidence that the full utilization of these tools can lead to early detection and control of foodborne diseases, enhancing public health and reducing the frequency of disease outbreaks.

Correlation between natural microbial load and formation of ropy slime affecting the superficial color of vacuum-packaged cooked sausage

The present study outlines a comprehensive correlation between the natural microbial load, which is predominantly composed of heat-resistant sporous-forming Bacillus, and the changes in the original properties related to the superficial color of vacuum-packaged cooked sausages. For this purpose, microbial growth curves were plotted by stimulating the growth of the natural microbiota in sausage packages at different temperatures. The correlations were investigated during sample incubation by the instrumental evaluation of color and the ropy slime detection on the sausage surface. The entrance of the natural microbiota into the stationary phase (ca. 9.3 log cfu/g) resulted in changes in the superficial color, which was demonstrated by the discoloration of vacuum-packaged cooked sausages. Therefore, it seems to be a suitable borderline for predictive models applied in durability studies that aim to estimate the period in which vacuum-packaged cooked sausages keep their typical superficial color, anticipating product refusal in markets.

Application of Electrochemical Biosensors for Determination of Food Spoilage

Food security is significantly affected by the mass production of agricultural produce and goods, the growing number of imported foods, and new eating and consumption habits. These changed circumstances bring food safety issues arising from food spoilage to the fore, making food safety control essential. Simple and fast screening methods have been developed to detect pathogens and biomarkers indicating the freshness of food for safety. In addition to the traditional, sequential, chemical analytical and microbiological methods, fast, highly sensitive, automated methods suitable for serial tests have appeared. At the same time, biosensor research is also developing dynamically worldwide, both in terms of the analytes to be determined and the technical toolkit. Consequently, the rapid development of biosensors, including electrochemical-based biosensors, has led to significant advantages in the quantitative detection and screening of food contaminants. These techniques show great specificity for the biomarkers tested and provide adequate analytical accuracy even in complex food matrices. In our review article, we summarize, in separate chapters, the electrochemical biosensors developed for the most important food groups and the food safety issues they can ensure, with particular respect to meat and fish products, milk and dairy products, as well as alcoholic and non-alcoholic beverages.

High-pressure processing and modified atmosphere packaging combinations for the improvement of dark, firm, and dry beef quality and shelf-life

This study investigated the effects of high-pressure processing (HPP) and modified atmosphere packaging (MAP) on 'dark, firm, and dry' (DFD) beef. To optimize the HPP, beef steaks (n = 180) were first processed at different pressures (0.1, 200, 300, 400, 500 MPa). It was found that 400 MPa enhanced DFD beef color and shelf-life. This optimized HPP (400 MPa) was combined with 3 MAP formulations, in a second study (40, 60, or 80% O₂-MAP), to determine their effect on DFD beef steaks. HPP (400 MPa) combined with MAP improved DFD beef L* and a*, color scores, and delayed discoloration (P < 0.01). Total plate counts for DFD beef held under 60% O₂-MAP was ≤6 log₁₀ CFU/g, even after 14 d of chilled storage. These same samples had shear force and TBARS values significantly lower than observed for DFD beef held under 80% O₂-MAP. HPP (400 MPa) combined with 60% O₂-MAP is recommended to improve DFD beef quality and shelf-life.

Optimization of a natural antimicrobial formulation against potential meat spoilage bacteria and food-borne pathogens: Mixture design methodology and predictive modeling

This study is about the combined antimicrobial effect of essential oils (EOs), namely Mediterranean (MN) EO, German thyme (GT) EO, Cinnamon (CN) EO, Indian (IN) EO, Asian (AN) EO, and citrus extract (CE) against spoilage bacteria (Lactobacillus sakei, Lactobacillus curvatus, Leuconostoc mesenteroides, Carnobacterium divergens, Brochothrix thermosphacta, and Pseudomonas aeruginosa) and selected pathogenic bacteria (E. coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes). Firstly, each EO and CE were screened for antibacterial activity by microdilution assay, and the most efficient antimicrobial extracts were selected based on the lowest MIC values to perform the combination assays. Afterward, a simplex-centroid mixture design was used to develop optimal antimicrobial mixtures capable of protecting meat from spoilage and pathogenic bacteria. The optimization tool allowed us to postulate models and validate them statistically as well as to create a prediction profile of the experiment. Thus, the optimal mixtures named active formulation 1 (AF1) containing MN EO/GT EO/VC EO/CE with a ratio of 1:2:2:1 and active formulation 2 (AF2) containing IN EO/AN EO/CE/VC EO with a ratio of 2:2:1:2, were developed based on the demonstration of their synergistic effect against tested bacteria. The obtained formulations at organoleptically acceptable concentrations could be applied in the preservation of meat and meat products.

Nanoemulsion-based approach to preserve muscle food: A review with current knowledge

Muscle foods are regarded as nutritionally dense foods while they are prone to spoilage by action of microorganism and oxidation. Recently, the consumer's preference is mostly toward minimally processed foods as well as preserved with natural preservatives. However, natural extract directly to the food matrix has several drawbacks. Hence development and applications of nanoemulsion has gained importance for the preservation of muscle foods to meet consumer requirements with enhanced food safety. Nanoemulsion utilizes natural extracts at much lower concentration with higher preservative abilities over original components. Nanoemulsions offer protection to the active component from degradation and ensure longer bioavailability. Novel techniques used for formulation of nanoemulsion provide stability to the emulsion with desirable qualities to improve their impacts. The application of nanoemulsion is known to enhance the preservative action of nanoemulsions by improving the microbial safety and oxidative stability in nanoform. This review provides recent updates on different methods used for formulation of nanoemulsions from different sources. Besides, successful application of nanoemulsion derived using natural agents for muscle food preservation and shelf life extension are reviewed. Thus, the application of nanoemulsion to extend shelf life and maintain quality is suggested for muscle foods.

Effects of UV-C Irradiation and Vacuum Sealing on the Shelf-Life of Beef, Chicken and Salmon Fillets

One-third of the world's food supply is lost, with meat being a major contributor to this loss. Globally, around 23% of all meat and 35% of all seafood products are lost or wasted. Meats and seafood products are susceptible to microbial spoilage during processing, storage, and distribution, where microbial contamination causes significant losses throughout the supply chain. This study examined the efficacy of UV-C irradiation and vacuum-sealing in preventing microbiological deterioration in beef, chicken, and salmon fillets. The samples were sterilized using a constant UV-C irradiation dose of 360 J/m² and stored under a reduced pressure of 40 kPa. A microbiological analysis was conducted daily to examine the microbial contamination, which included counting the colonies of Pseudomonas spp., aerobic bacteria, lactic acid bacteria (LAB), Salmonella, and Escherichia coli, as well as monitoring the increase in pH levels. The results demonstrated a statistically significant difference (p > 0.05) in the aerobic bacteria counts between the storage conditions and storage days in all samples, which is a primary indicator of microbial spoilage. In contrast, the differences varied in the Pseudomonas spp. and LAB counts between the storage conditions and storage days, and there was no significant difference (p < 0.05) in the pH levels between the storage conditions. The results indicate that the combination of UV-C irradiation and vacuum sealing effectively inhibits microbial growth and extends the shelf-life of beef, chicken, and salmon fillets by 66.6%.

Influence of surface properties on the adhesion of bacteria onto different casings

Bacteria adhere to the surfaces of sausage casing and form biofilms, which causes food spoilage and quality deterioration. However, bacterial adhesion to the casing surfaces has not received enough attention and has not been extensively studied. In this study, the effect of the physicochemical properties of casing surfaces on bacterial initial adhesion were investigated with Leuconostoc mesenteroides as model bacteria. The adhesion of Leuconostoc mesenteroides onto 5 types of casings were systematically investigated, including animal casings, collagen casings, cellulose casings, fiber casings, and nylon casings, which are the most frequently encountered casings in sausage processing. It was found that the number of viable cells on the casings following the trend as: animal casings > collagen casings > fiber casings > cellulose casings > nylon casings after 4 h of incubation time. This phenomenon might be due to the different physicochemical properties of the different casings. Therefore, physicochemical factors, including zeta potential, hydrophobicity and roughness of casings, zeta potential and hydrophobicity of Leuconostoc mesenteroides, were further characterized. In terms of hydrophobic interactions, the results showed that the number of bacteria attached to the casings did not conform to the trend of hydrophobic interaction. In terms of electrostatic interactions, the results showed that the number of bacteria attached to the casings did not conform to the trend of hydrophobic interaction. The casings with different surface roughnesses in a range of 1.67-20.83 μm, the variation of bacterial adhesion quantity was in good agreement with the variation trend of casing roughness, the result showed that the surface roughness was the key factor dominating the bacterial adhesion rate compared with the surface hydrophobicity and zeta potential. The results give new insights to explore the mechanism of bacterial adhesion on casings and prevent sausage spoilage.

Growth and survival of common spoilage and pathogenic bacteria in ground beef and plant-based meat analogues

To better understand the microbial quality and safety of plant-based meat analogues, this study investigated the changes of native microflora present in soy- and pea-based meat analogues (SBM and PBM) and compared them with ground beef (GB). SBM, PBM, and GB were also artificially inoculated with meat spoilage microorganisms, Pseudomonas fluorescens and Brochothrix thermosphacta, and pathogenic microorganisms, Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes; the fitness of these bacteria was evaluated during storage at refrigerated and/or abused temperatures. Results showed that the initial total aerobic plate count (APC), coliform, lactic acid bacteria (LAB), and mold/yeast (M/Y) counts for GB could be as high as 5.44, 2.90, 4.61, and 3.45 log CFU/g, while the highest initial APC, coliform, LAB, and M/Y counts found in SBM were 3.10, 2.00, 2.04, and 1.95 log CFU/g, and were 3.82, 2.51, 3.61, and 1.44 log CFU/g for PBM. The batch-to-batch differences in microbial counts were more significant in GB than in SBM and PBM. Despite the different initial concentrations, there was no difference among APC and LAB counts between the three meat types by the end of the 10-day 4 °C storage period, all approaching ca. 7.00 log CFU/g. Artificially-inoculated B. thermosphacta increased by 0.76, 1.58, and 0.96 log CFU/g in GB, PBM, and SBM respectively by the end of the refrigeration storage; P. fluorescens increased by 4.92, 3.00, and 0.40 log CFU/g in GB, PBM, and SBM respectively. Under refrigerated storage conditions, pathogenic bacteria did not change in GB and SBM. L. monocytogenes increased by 0.74 log in PBM during the 7-day storage at 4 °C. All three pathogens grew at abused storage temperatures, regardless of the meat type. Results indicated that plant-based meat could support the survival and even growth of spoilage and pathogenic microorganisms. Preventive controls are needed for ensuring the microbial quality and safety of plant-based meat analogues.

Thériault W, Longpré J, Thibodeau A, Hocine MN, Fravalo P. Distinct Microbiotas Are Associated with Different Production Lines in the Cutting Room of a Swine Slaughterhouse

The microorganisms found on fresh, raw meat cuts at a slaughterhouse can influence the meat's safety and spoilage patterns along further stages of processing. However, little is known about the general microbial ecology of the production environment of slaughterhouses. We used 16s rRNA sequencing and diversity analysis to characterize the microbiota heterogeneity on conveyor belt surfaces in the cutting room of a swine slaughterhouse from different production lines (each associated with a particular piece/cut of meat). Variation of the microbiota over a period of time (six visits) was also evaluated. Significant differences of alpha and beta diversity were found between the different visits and between the different production lines. Bacterial genera indicative of each visit and production line were also identified. We then created random forest models that, based on the microbiota of each sample, allowed us to predict with 94% accuracy to which visit a sample belonged and to predict with 88% accuracy from which production line it was taken. Our results suggest a possible influence of meat cut on processing surface microbiotas, which could lead to better prevention, surveillance, and control of microbial contamination of meat during processing.

Gelatin-Based Film as a Color Indicator in Food-Spoilage Observation: A Review

The color indicator can monitor the quality and safety of food products due to its sensitive nature toward various pH levels. A color indicator helps consumers monitor the freshness of food products since it is difficult for them to depend solely on their appearance. Thus, this review could provide alternative suggestions to solve the food-spoilage determination, especially for perishable food. Usually, food spoilage happens due to protein and lipid oxidation, enzymatic reaction, and microbial activity that will cause an alteration of the pH level. Due to their broad-spectrum properties, natural sources such as anthocyanin, curcumin, and betacyanin are commonly used in developing color indicators. They can also improve the gelatin-based film's morphology and significant drawbacks. Incorporating natural colorants into the gelatin-based film can improve the film's strength, gas-barrier properties, and water-vapor permeability and provide antioxidant and antimicrobial properties. Hence, the color indicator can be utilized as an effective tool to monitor and control the shelf life of packaged foods. Nevertheless, future studies should consider the determination of food-spoilage observation using natural colorants from betacyanin, chlorophyll, and carotenoids, as well as the determination of gas levels in food spoilage, especially carbon dioxide gas.

Shelf-Life Evaluation of Pork Loins as Influenced by the Application of Different Antimicrobial Interventions

The objective of the study was to determine the impact of antimicrobial interventions and refrigerated dark storage on the shelf-life of pork chops. Boneless pork loins (n = 36) were split and stored for 1, 14, 28, and 42 days at 2–4 °C after being treated with the following antimicrobials: water (WAT), Bovibrom 225 ppm (BB225), Bovibrom 500 ppm (BB500), Fit Fresh 3 ppm (FF3), or washing solution 750 ppm (WS750). After the end of dark storage, pork loins were further processed and sliced into chops, overwrapped in trays, and displayed for up to an additional 96 h in a retail case. Instrumental and visual color measurements as well as mesophilic and psychrotrophic aerobic bacteria, and lactic acid bacteria were measured. BB500 and FF3 performed better in inhibiting the growth of indicator bacteria under 6 logs; however, FF3 presented the best stability for color during storage. Principal component analysis clustered initial dark storage days with a* and chroma while % discoloration, hue, b* and microorganisms where clustered with longer dark storage times. In general, treatment FF3 presented the best performance, both in inhibiting microbial growth and maintaining the stability of color, thus increasing the shelf-life of pork loins.

Lactic Acid Bacteria and Bacteriocins: Novel Biotechnological Approach for Biopreservation of Meat and Meat Products

Meat and meat products are perishable in nature, and easily susceptible to microbial contamination and chemical deterioration. This not only results in an increased risk to health of consumers, but also causes economic loss to the meat industry. Some microorganisms of the lactic acid bacteria (LAB) group and their ribosomal-synthesized antimicrobial peptides-especially bacteriocins-can be used as a natural preservative, and an alternative to chemical preservatives in meat industry. Purified or partially purified bacteriocins can be used as a food additive or incorporated in active packaging, while bacteriocin-producing cells could be added as starter or protective cultures for fermented meats. Large-scale applications of bacteriocins are limited, however, mainly due to the narrow antimicrobial spectrum and varying stability in different food matrixes. To overcome these limitations, bioengineering and biotechnological techniques are being employed to combine two or more classes of bacteriocins and develop novel bacteriocins with high efficacy. These approaches, in combination with hurdle concepts (active packaging), provide adequate safety by reducing the pathogenicity of spoilage microorganisms, improving sensory characteristics (e.g., desirable flavor, texture, aroma) and enhancing the shelf life of meat-based products. In this review, the biosynthesis of different classes of LAB bacteriocins, their mechanism of action and their role in the preservation of meats and meat products are reviewed.

M I. Warmed-over flavour profiles, microbial changes, shelf-life and check-all-that-apply sensory analysis of cooked minced pork treated with varying levels of Moringa oleifera leaf and root powder

This study investigated warmed-over flavour profiles, microbial changes, shelf-life and sensory characteristics of minced cooked pork treated with Moringa oleifera (M. oleifera) root and leaf powder during refrigerated storage at 4 °C. A total of 8 treatments (control = no antioxidant; 0.5ML = 0.5% M. oleifera leaf; 1ML = 1% M. oleifera leaf; 0.5MR = 0.5 % M. oleifera root; 1MR = 1% M. oleifera root; 0.5MLR = 0.5% M. oleifera leaf and root mixed; 1MLR = 1% M. oleifera leaf and root mixed; BHT = 0.02% butylated hydroxytoluene) were evaluated. The minimum inhibitory concentration (MIC) of the plant extracts against the test bacteria was determined using the serial dilution in 96 well microtiter plates technique. Warmed-over flavour profiles were determined using the test for carbonyls assay where hexanal was used as a marker for warmed-over flavour. The check-all-that-apply sensory tool was used to characterise minced cooked pork treated with different antioxidants according to warmed-over flavour taste and odour intensities. The results showed that the antibacterial assay of the extracts exhibited a broad-spectrum of activity against the tested bacteria. The leaf extracts demonstrated better activity against both gram-negative and gram-positive bacteria, with most of the MICs at less than 1 mg/mL, while the root performed better against gram-negative bacteria compared to gram-positive bacteria. There was a significant rapid increase in the warmed-over flavour profiles of the control compared to the M. oleifera and BHT treated pork. The pork samples which had M. oleifera leaf, root, and their combination at inclusion levels of 1% and 0.5% displayed lower warmed-over flavour profiles that fell in the range (1.0–1.46 mg hexanal/100g fat) throughout the storage period. Consumer sensory evaluation revealed that pork samples treated with the highest inclusion level (1%) of the M. oleifera leaf powder received the lowest consumer rating scores for appearance. Based on these results, adding M. oleifera leaf and root powder can decrease warmed-over flavour development and improve the shelf-life of processed pork. Furthermore, the incorporation of M. oleifera root powder can potentially be more acceptable to consumers because of its colour compared to the leaf, which gives the product a green colour that may not be pleasant for some consumers. This suggests that the inclusion of the root powder at 1% may be well accepted for consumption by consumers.

Reversible AIE-active fluorescent probe with a large emission peak shift for ratiometric detection of food freshness indicator H2S

It is crucial to on-site monitor H₂S for addressing the concerns associated with food safety. We rationally prepared an AIE-active fluorescent probe (CLBZ) with the aggregated state conversion for sensing H₂S in a ratiometric response manner. CLBZ displayed ratiometric response, fast response time (5 s), well-resolved emission peak shift (147 nm) and high selectivity towards H₂S, and it can be used as a reversible and reusable probe. The probe-based test strip was also developed to conveniently detect H₂S generated during food spoilage in the absence of laboratory instruments. It achieved the consistent results and sensitivity with that determined by the colony forming unit (CFU) assay. These results paved a successful way to develop an effective analytical method for food quality and safety.

Dynamics of microbiota in the imported beef primal cuts during storage at different chilled temperatures

Primal cuts of Australian beef transported by sea were stored under different chilled temperatures (0, 2, and 4 °C) for six weeks in different packaging conditions (aerobic or anaerobic packaging). The number of microorganisms and the transition of the microbiota were investigated using culture methods and amplicon sequencing. After six weeks of storage, the beef tended to show a high total viable count under aerobic packaging conditions and a high lactic acid bacteria count under anaerobic packaging conditions. The result of amplicon sequencing analysis showed that different beef samples had different predominant bacterial groups. Moreover, at high storage temperatures, Serratia sp. having high putrefactive activity showed increased abundance, while at low storage temperatures, Lactobacillus sp. showed increased abundance. Thus, differences in the packaging conditions and distribution temperatures after import affect the number of bacteria and the type of microorganisms in the Australian beef primal cuts, which may affect their quality.

Involvement of AprD in regulating biofilm structure, matrix secretion, and cell metabolism of meat-borne Pseudomonas fragi during chilled storage

Pseudomonas fragi is by far one of the most threatening species in the spoilage of chilled meat that is stored under aerobic conditions. The membrane protein AprD is a well-established regulator controlling protease secretion in Pseudomonas spp. However, its exact roles in modulating metabolic pathways and spoilage potential of P. fragi at the molecular level remain undefined. Here, an in-frame deletion mutation of aprD was used to explore the impacts on their biofilm structure, matrix secretion, and cell metabolism. The results showed that ΔaprD formed relatively disorganized loose aggregation in biofilm, resulting in a thinner structure and more dead cells. Meanwhile, marked changes in the content of extracellular carbohydrates and proteins were observed. Furthermore, intracellular metabolomic profiling revealed the involvement of aprD in several cellular metabolic pathways, mostly including the carbohydrate pathway, amino acid pathway, and nucleotide pathway, while the characterization of extracellular metabolism clarified the variations in the spoilage-related metabolites (e.g., creatine, IMP, spermine, fatty acids, amino acids, and oligopeptides) could be highly correlated with aprD deletion. In this finding, we indicated that aprD could be responsible for cell reproduction and in situ spoilage potential of P. fragi NMC25 during chilled storage by controlling related metabolism and nutrients utilization. Thus, our results will contribute to an improved understanding of the regulatory mechanism of aprD gene in meat spoilage contaminated with P. fragi, which can be valuable to ensure the quality and safety of meat.

Microbial Contamination and Public Health: An Overview

Food contamination with microbial agents can take place at any stage of the food chain, from farm to fork. For this reason, good hygienic and manufacturing practices must be followed along the entire food chain to prevent microbiological food contamination due to microbes which can cause high incidence of morbidity and mortality among consumers. Recent research have been focused on the implementation of innovative technologies for enhancing the quality and safety of food without compromising its organoleptic and nutritional characteristics. Studies should be addressed to the development of simple, less expensive, and fast tests for monitoring and controlling microbial food contamination, as well as to the development of new food manufacturing processes.

Chemiresistive NH3 detection at sub-zero temperatures by polypyrrole- loaded Sn1-xSbxO2 nanocubes

Chemiresistive gas sensors operate mainly at high temperatures, primarily due to the need of energy for surface adsorption-desorption of analytes. As a result, the operating temperature of the chemiresistive sensors could be reduced only to room temperature. Hence, a plethora of sensing requirements at temperatures below ambient have remained outside the scope of chemiresistive materials. In this work, we have developed an antimony-doped SnO₂ nanocube-supported expanded polypyrrole network that could detect low ppm ammonia gas (≤20 ppm) at sub-zero temperatures with high response (∼4), selectivity, and short response and recovery times. The low temperature chemiresistive sensing has been explained in terms of the interplay of an extended conducting network of an in situ deposited polymer, effective transport properties of majority charge carriers and a loosely bound exciton-like electron-hole pair formation and breakage mechanism.

Critical review and recent advances of 2D materials-Based gas sensors for food spoilage detection

Many people around the world are concerned about meat safety and quality, which has resulted in the ongoing advancement of packaged food technology. Since the emergence of graphene in 2004, the number of studies on layered two-dimensional materials (2DMs) for applications ranging from food packaging to meat quality monitoring has been expanding quickly. Recently, scientists have been working hard to develop a novel class of 2DMs that keep the good things about graphene but don't have zero bandgaps at room temperature. Much work has been done on layered transition metal dichalcogenides (TMDCs) like different metal sulfides and selenides for meat spoilage gas sensors. This review looks at (i) the main indicators of meat spoilage and (ii) the detection methods that can be used to find out if meat has been spoiled, such as chemiresistive, electrochemical, and optical methods. (iii) the role of 2DMs in meat spoilage detection and (iv) the emergence of advanced methods for selective classification of target analytes in meat/food spoilage detection in recent years. Thus, this review demonstrates the potential scope of 2DMs for developing intelligent sensor systems for food and meat spoilage detection with high viability, simplicity, cost-effectiveness, and other multipurpose tools.

Similar Carcass Surface Microbiota Observed Following Primary Processing of Different Pig Batches

Bacterial contamination during meat processing is a concern for both food safety and for the shelf life of pork meat products. The gut microbiota of meat-producing animals is one of the most important sources of surface contamination of processed carcasses. This microbiota is recognized to vary between pigs from different farms and could thus be reflected on the bacterial contamination of carcasses at time of processing. In this study, the microbiota of 26 carcasses of pigs originating from different farms (i.e., batches) were compared to determine if an association could be observed between carcass surface microbiota (top and bottom) and the origin of slaughtered animals. The microbiota of the top and bottom carcass surface areas was analyzed by culturing classical indicator microorganisms (mesophilic aerobic bacteria, Enterobacteria, Escherichia coli, Pseudomonas, and lactic bacteria), by the detection of Salmonella, and by 16S rRNA gene sequencing. Culture results showed higher Enterobacteria, E. coli, and lactic bacteria counts for the bottom areas of the carcasses (neck/chest/shoulder) when compared to the top areas. Salmonella was not detected in any samples. Globally, 16S rRNA gene sequencing showed a similar composition and diversity between the top and bottom carcass areas. Despite the presence of some genera associated with fecal contamination such as Terrisporobacter, Escherichia-Shigella, Turicibacter, Clostridium sensustricto1, and Streptococcus on the carcass surface, sequencing analysis suggested that there was no difference between the different batches of samples from the top and bottom areas of the carcasses. The primary processing therefore appears to cause a uniformization of the carcass global surface microbiota, with some specific bacteria being different depending on the carcass area sampled.