Recent advances in bio-preservatives impacts of lactic acid bacteria and their metabolites on aquatic food products

Edible Coatings for Fish Preservation: Literature Data on Storage Temperature, Product Requirements, Antioxidant Activity, and Coating Performance-A Review

Fresh fish is among the most nutritive foodstuffs, but it is also the most perishable one. Therefore, huge efforts have been made to find the most suitable tools to deliver fish of the highest quality to exigent consumers. Scientific studies help the industry to exploit the newest findings to scale up emerging industrial technologies. In this review article, the focus is on the latest scientific findings on edible films used for fish coatings and storage. Since today's packaging processing and economy are governed by sustainability, naturality underpins packaging science. The synthesis of edible coatings, their components, processing advantages, and disadvantages are outlined with respect to the preservation requirements for sensitive fish. The requirements of coating properties are underlined for specific scenarios distinguishing cold and freezing conditions. This review raises the importance of antioxidants and their role in fish storage and preservation. A summary of their impact on physical, chemical, microbiological, and sensory alterations upon application in real fish is given. Studies on their influence on product stability, including pro-oxidant activity and the prevention of the autolysis of fish muscle, are given. Examples of lipid oxidation and its inhibition by the antioxidants embedded in edible coatings are given together with the relationship to the development of off-odors and other unwanted impacts. This review selects the most significant and valuable work performed in the past decade in the field of edible coatings whose development is on the global rise and adheres to food waste and sustainable development goals 2 (zero hunger), 3 (good health and well-being), and 12 (responsible consumption and production).

Biopreservation of Fresh Sardines (Sardina pilchardus) Using Lactiplantibacillus plantarum OV50 Isolated from Traditional Algerian Green Olives Preparations

Lactiplantibacillus plantarum OV50 is a novel strain that was isolated from Algerian olives. Prior to its use as a natural biopreservative, OV50 underwent characterization for various functions. OV50 shows no proteolytic, lipolytic, or hemolytic activity. In addition, it is non-cytotoxic to eukaryotic cells and does not exhibit acquired antibiotic resistance. OV50 was tested with Pseudomonas aeruginosa ATCC 27835, Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Vibrio cholerae ATCC 14035 in a sardine based-medium at 37 °C and 7 °C. At 37 °C, OV50 completely inhibited the growth of these foodborne pathogens for a maximum of 6 h. At 7 °C, it suppressed their growth for a maximum of 8 days, except for S. aureus ATCC 6538, whose growth was reduced from 4 to 2 log CFU/mL. Microbiological counts, total volatile basic nitrogen (TVB-N), and peroxide values (PV) concentrations were determined in fresh sardines inoculated with OV50 and kept at 7 °C for 12 days. The inoculated sardines showed a significant reduction in TVB-N levels at D8 (34.9 mg/100 g) compared to the control (59.73 mg/100 g) and in PV concentrations at D4 (6.67 meq/kg) compared to the control (11.44 meq/kg), as well as a significant reduction in the numbers of Enterobacterales, Coliforms, Pseudomonas spp., Vibrio spp., and S. aureus At D8 and D12 compared to the control. Taken together, these results indicate that OV50 can improve the microbiological safety, freshness, and quality of sardines.

Natural Antimicrobials: A Reservoir to Contrast Listeria monocytogenes

Natural environments possess a reservoir of compounds exerting antimicrobial activity that are forms of defence for some organisms against others. Recently, they have become more and more attractive in the food sector due to the increasing demand for natural compounds that have the capacity to protect food from pathogenic microorganisms. Among foodborne pathogens, Listeria monocytogenes can contaminate food during production, distribution, or storage, and its presence is especially detected in fresh, raw food and ready-to-eat products. The interest in this microorganism is related to listeriosis, a severe disease with a high mortality rate that can occur after its ingestion. Starting from this premise, the present review aims to investigate plant extract and fermented plant matrices, as well as the compounds or mixtures of compounds produced during microbial fermentation processes that have anti-listeria activity.

Characterization and Mechanism of Tea Polyphenols Inhibiting Biogenic Amine Accumulation in Marinated Spanish Mackerel

Putrescine is a low-molecular-weight organic compound that is widely found in pickled foods. Although the intake of biogenic amines is beneficial to humans, an excessive intake can cause discomfort. In this study, the ornithine decarboxylase gene (ODC) was involved in putrescine biosynthesis. After cloning, expression and functional verification, it was induced and expressed in E. coli BL21 (DE3). The relative molecular mass of the recombinant soluble ODC protein was 14.87 kDa. The function of ornithine decarboxylase was analyzed by determining the amino acid and putrescine content. The results show that the ODC protein could catalyze the decarboxylation of ornithine to putrescine. Then, the three-dimensional structure of the enzyme was used as a receptor for the virtual screening of inhibitors. The binding energy of tea polyphenol ligands to the receptor was the highest at -7.2 kcal mol^-1. Therefore, tea polyphenols were added to marinated fish to monitor the changes in putrescine content and were found to significantly inhibit putrescine production (p < 0.05). This study lays the foundation for further research on the enzymatic properties of ODC and provides insight into an effective inhibitor for controlling the putrescine content in pickled fish.

Integrated Microbiota and Metabolome Analysis to Assess the Effects of the Solid-State Fermentation of Corn-Soybean Meal Feed Using Compound Strains

Solid-state fermentation is known to improve plant-based feed nutritional quality; however, the association between microbes and metabolite production in fermented feed remains unclear. We inoculated corn-soybean-wheat bran (CSW) meal feed with Bacillus licheniformis Y5-39, Bacillus subtilis B-1, and lactic acid bacteria RSG-1. Then, 16S rDNA sequencing and untargeted metabolomic profiling were applied to investigate changes in the microflora and metabolites, respectively, and their integrated correlations during fermentation were assessed. The results indicated that trichloroacetic acid soluble protein levels showed a sharp increase, while glycinin and β-conglycinin levels showed a sharp decrease in the fermented feed, as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Pediococcus, Enterococcus, and Lactobacillus were predominant in the fermented feed. Overall, 699 significantly different metabolites were identified before and after fermentation. Arginine and proline, cysteine and methionine, and phenylalanine and tryptophan metabolism were the key pathways, with arginine and proline metabolism being the most important pathway in the fermentation process. By analyzing the correlation between the microbiota and metabolite production, lysyl-valine and lysyl-proline levels were found to be positively correlated with Enterococcus and Lactobacillus abundance. However, Pediococcus was positively correlated with some metabolites contributing to nutritional status and immune function. According to our data, Pediococcus, Enterococcus, and Lactobacillus mainly participate in protein degradation, amino acid metabolism, and lactic acid production in fermented feed. Our results provide new insights into the dynamic changes in metabolism that occurred during the solid-state fermentation of corn-soybean meal feed using compound strains and should facilitate the optimization of fermentation production efficiency and feed quality.

Impacts of nano/micro-plastics on safety and quality of aquatic food products

The spread of nano/microplastics (N/MPs) pollution has gained importance due to the associated health concerns. Marine environment including fishes, mussels, seaweed and crustaceans are largely exposed to these potential threats. N/MPs are associated with plastic, additives, contaminants and microbial growth, which are transmitted to higher trophic levels. Foods from aquatic origin are known to promote health and have gained immense importance. Recently, aquatic foods are traced to transmit the nano/microplastic and the persistent organic pollutant poising hazard to humans. However, microplastic ingestion, translocation and bioaccumulation of the contaminant have impacts on animal health. The level of pollution depends upon the pollution in the zone of growth for aquatic organisms. Consumption of contaminated aquatic food affects the health by transferring the microplastic and chemicals. This chapter describes the sources and occurrence of N/MPs in marine environment, detailed classification of N/MPs based on the properties influencing associated hazard. Additionally, occurrence of N/MPs and their impact on quality and safety in aquatic food products are discussed. Lastly, existing regulations and requirements of a robust framework of N/MPs are reviewed.

Exploring the effect of Lactiplantibacillus plantarum Lac 9-3 with high adhesion on refrigerated shrimp: Adhesion modeling and biopreservation evaluation

Lactic acid bacteria (LAB) have recently become ideal candidates for developing food biopreservatives. Adhesion is critical for LAB to perform biocontrol functions in food processing and preservation. In this study, we innovatively proposed an effective adhesion evaluation model related to the surface properties of LAB to excavate a LAB strain with high adhesion on the surface of shrimp. Then, the biocontrol potential regarding the quality of refrigerated shrimp was explored, especially for protein quality. The screening of highly adherent LAB was performed using 54 LAB strains tolerant to the low temperature (4 °C) and present antimicrobial activity. Based on surface hydrophobicity, autoaggregation, and biofilm formation, a new method for predicting LAB adhesion was established by stepwise multiple linear regression. The most relevant relationship between adhesion and biofilm formation was derived from the model. Lactiplantibacillus plantarum Lac 9-3 stood out for the strongest adhesion on the shrimp surface and the highest antimicrobial activity. The preservation results showed that Lac 9-3 significantly (p < 0.05) retarded the accumulation of total volatile basic nitrogen (TVB-N) and the growth of spoilage bacteria. The damage to the texture properties of shrimp was inhibited. Meanwhile, the degradation of myofibrillar protein was alleviated, including a significant delay (p < 0.05) in sulfhydryl (SH) group reduction, surface hydrophobicity increases, and protein conformation changes. This research optimized the evaluation of the bacteria adhesion potential, providing a new idea for developing biocontrol strategies to extend the commercial life of aquatic products.

Effect of Thymus vulgaris L. essential oil and thymol on the microbiological properties of meat and meat products: A review

Since foodborne diseases are often considered as one of the biggest public health threats worldwide, effective preservation strategies are needed to inhibit the growth of undesirable microorganisms in food commodities. Up to now, several techniques have been adopted for the production of safe and high-quality products. Although the traditional methods can improve the reliability, safety, and shelf-life of food, some of them cannot be applied without rising health concerns. Thereby, the addition of various phytochemicals has gained much attention during the last decades, especially for meat products that may be contaminated with pathogenic and spoilage organisms. Thyme (Thymus vulgaris L.), as an important medicinal and culinary herb, is a promising source of bioactive compounds that have a great impact on the microbiological stability of meat by suppressing the undesirable microflora. However, the use of these antimicrobials is still facing difficulties due to their aromatic properties and variable efficacy against targeted species. In this paper, we provide an overview on the potential effects of thyme essential oil (EO) and thymol as bio-preservative agents in meat products. Furthermore, this paper provides insights into the limitations and current challenges of the addition of EOs and their constituents to meat commodities and suggests viable solutions that can improve the applicability of these phytochemicals.

Antimicrobial Impacts of Microbial Metabolites on the Preservation of Fish and Fishery Products: A Review with Current Knowledge

Microbial metabolites have proven effects to inhibit food spoilage microbiota, without any development of antimicrobial resistance. This review provides a recent literature update on the preservative action of metabolites derived from microorganisms on seafood. Fish and fishery products are regarded as a myriad of nutrition, while being highly prone to spoilage. Several proven controversies (antimicrobial resistance and health issues) related to the use of synthetic preservatives have caused an imminent problem. The demand for minimally processed and naturally preserved clean-label fish and fishery products is on rise. Metabolites derived from microorganisms have exhibited diverse preservation capacities on fish and fishery products' spoilage. Inclusions with other preservation techniques, such as hurdle technology, for the shelf-life extension of fish and fishery products are also summarized.

Dissecting of the AI-2/LuxS Mediated Growth Characteristics and Bacteriostatic Ability of Lactiplantibacillus plantarum SS-128 by Integration of Transcriptomics and Metabolomics

Lactiplantibacillus plantarum could regulate certain physiological functions through the AI-2/LuxS-mediated quorum sensing (QS) system. To explore the regulation mechanism on the growth characteristics and bacteriostatic ability of L. plantarum SS-128, a luxS mutant was constructed by a two-step homologous recombination. Compared with ΔluxS/SS-128, the metabolites of SS-128 had stronger bacteriostatic ability. The combined analysis of transcriptomics and metabolomics data showed that SS-128 exhibited higher pyruvate metabolic efficiency and energy input, followed by higher LDH level and metabolite overflow compared to ΔluxS/SS-128, resulting in stronger bacteriostatic ability. The absence of luxS induces a regulatory pathway that burdens the cysteine cycle by quantitatively drawing off central metabolic intermediaries. To accommodate this mutations, ΔluxS/SS-128 exhibited lower metabolite overflow and abnormal proliferation. These results demonstrate that the growth characteristic and metabolism of L. plantarum SS-128 are mediated by the AI-2/LuxS QS system, which is a positive regulator involved in food safety. It would be helpful to investigate more bio-preservation control potential of L. plantarum, especially when applied in food industrial biotechnology.