Diversity of the bacterial community in Myanmar traditional salted fish yegyo ngapi

Phylogenetically diverse bacterial species produce histamine

Histamine is an important biogenic amine known to impact a variety of patho-physiological processes ranging from allergic reactions, gut-mediated anti-inflammatory responses, and neurotransmitter activity. Histamine is found both endogenously within specialized host cells and exogenously in microbes. Exogenous histamine is produced through the decarboxylation of the amino acid L-histidine by bacterial-derived histidine decarboxylase enzymes. To investigate how widespread histamine production is across bacterial species, we examined 102,018 annotated genomes in the Integrated Microbial Genomes Database and identified 3,679 bacterial genomes (3.6 %) which possess the enzymatic machinery to generate histamine. These bacteria belonged to 10 phyla: Bacillota, Bacteroidota, Actinomycetota, Pseudomonadota, Lentisphaerota, Fusobacteriota, Armatimonadota, Cyanobacteriota, Thermodesulfobacteriota, and Verrucomicrobiota. The majority of the identified bacteria were terrestrial or aquatic in origin, although several bacteria originated in the human gut microbiota. We used liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based targeted metabolomics to confirm our genome discoveries correlated with L-histidine-to-histamine conversion in a chemically defined bacterial growth medium by a cohort of select environmental and human gut bacteria. We found that environmental microbes Vibrio harveyi, Pseudomonas fluorescens and Streptomyces griseus generated considerable levels of histamine (788 - 8,730 ng/mL). Interestingly, we found higher concentrations of histamine produced by gut-associated Fusobacterium varium, Clostridium perfringens, Limosilactobacillus reuteri and Morganella morganii (8,510--82,400 ng/mL). This work expands our knowledge of histamine production by diverse microbes.

Effects of curing concentration and drying time on flavor and microorganisms in dry salted Spanish mackerel

This study investigated the quality changes of dry salted mackerel during curing and drying process and the relationship between flavor substances and microorganisms. The results showed that the thiobarbituric acid reactive substances (TBARS) values increased gradually with the increase of salt concentration and treatment time. The total volatile base nitrogen (TVB-N) values and total viable counts (TVC) values showed the same trend. Under 3% condition, the TVB-N values exceeded the standard and was not suitable for consumption. A total of 61 volatile flavor substances were identified by Gas chromatography-ion mobility spectrometry (GC-IMS), among which aldehydes contributed the most. Staphylococcus and Cobetia were the most abundant by High-throughput sequencing (HTS). There was significant correlation between TOP15 microorganisms and TOP20 flavor substances. Staphylococcus and Cobetia were positively correlated with 13 volatile flavor substances, which contributed to the formation of flavor in naturally fermented Spanish mackerel.

Fermented fish and fermented fish-based products, an ever-growing source of microbial diversity: A literature review

Fermented fish and fermented fish-based products are part of the diet of many countries all over the world. Their popularity is not only due to the unique flavor, the distinct texture, and the good nutritional quality, but also to the easiness of the production process, that is commonly based on empirical traditional methods. Fish fermentation techniques ususally rely on the combination of some key steps, including salting, addition of spices or additives, and maintenance of anaerobic conditions, thus selecting for the multiplication of some pro-technological microorganisms. The objective of the present review was to provide an overview of the current knowledge of the microbial communities occurring in fermented fish and fish-based products. Specific information was collected from scientific publications published from 2000 to 2022 with the aim of generating a comprehensive database. The production of fermented fish and fish-based foods was mostly localized in West African countries, Northern European countries, and Southeast Asian countries. Based on the available literature, the microbial composition of fermented fish and fish-based products was delineated by using viable counting combined with identification of isolates, and culture-independent techniques. The data obtained from viable counting highlighted the occurrence of microbial groups usually associated with food fermentation, namely lactic acid bacteria, staphylococci, Bacillus spp., and yeasts. The identification of isolates combined with culture-independent methods showed that the fermentative process of fish-based products was generally guided by lactobacilli (Lactiplantibacillus plantarum, Latilactobacillus sakei, and Latilactobacillus curvatus) or Tetragenococcus spp. depending on the salt concentration. Among lactic acid bacteria populations, Lactococcus spp., Pediococcus spp., Leuconostoc spp., Weissella spp., Enterococcus spp., Streptococcus spp., and Vagococcus spp. were frequently identified. Staphylococcus spp. and Bacillus spp. confirmed a great adaptation to fermented fish-based products. Other noteworthy bacterial taxa included Micrococcus spp., Pseudomonas spp., Psychrobacter spp., Halanaerobium spp., and Halomonas spp. Among human pathogenic bacteria, the occurrence of Clostridium spp. and Vibrio spp. was documented. As for yeast populations, the predominance of Candida spp., Debaryomyces spp., and Saccharomyces spp. was evidenced. The present literature review could serve as comprehensive database for the scientific community, and as a reference for the food industry in order to formulate tailored starter or adjunctive cultures for product improvement.

The Potential of Fermented Food from Southeast Asia as Biofertiliser

The intensive amount of chemical usage in agricultural practices could contribute to a significant impact on food safety issues and environmental health. Over-usage of chemical fertilisers may alter soil characteristics and contaminate water sources, leading to several human and animal health issues. Recently, there have been efforts to use microbial biofertilisers as a more sustainable and environmentally friendly agricultural practice in the common household of Southeast Asia. Traditionally, this method tends to utilise leftover food materials and readily available bacterial cultures, such as yoghurt drinks, and ferment them under a specific period in either solid or liquid form. So far, most of the testimonial-based feedbacks from local communities have been positive, but only limited information is available in the literature regarding the usage of biofertiliser fermented food (BFF). Previously, raw food waste has been used in the agriculture system to promote plant growth, however, the functional role of fermented food in enhancing plant growth have yet to be discovered. An understanding of the symbiotic relationship between fermented food and plants could be exploited to improve agricultural plant production more sustainably. Fermented food is known to be rich in good microbial flora (especially lactic acid bacteria (LAB)). LAB exist in different sources of fermented food and can act as a plant growth-promoting agent, improving the nutrient availability of food waste and other organic materials. Therefore, in this review, the potential use of seafood-based, plant-based, and animal-based fermented food as biofertiliser, especially from Southeast Asia, will be discussed based on their types and microbial and nutritional contents. The different types of fermented food provide a wide range of microbial flora for the enrichment of proteins, amino acids, vitamins, and minerals content in enhancing plant growth and overall development of the plant. The current advances of biofertiliser and practices of BFF will also be discussed in this review.

Traditional fermented foods as vehicle of non-dairy probiotics: Perspectives in South East Asia countries

Food fermentation is a food processing technology that utilizes the growth and metabolic activity of microorganisms for the stabilization and transformation of food materials. Notwithstanding, the technology has evolved beyond food preservation into a tool for creating desirable organoleptic, nutritional, and functional attributes in food products. This narrative review outlines a compilation of traditional fermented foods which available in the South East Asia (SEA) regions as a source vehicle for non-dairy probiotics. The nutritional values of traditional fermented foods are well-appreciated, especially in the resource-poor regions. The sensory and organoleptic preferences of traditional fermented foods as means of dietary routine variations were demonstrated. Furthermore, the evidence underlying its potent impacts on public health promotion and disease prevention is outlined. Lastly, the challenges and future prospects for the integration of traditional fermented foods practice are elucidated.

Fermented fish products in South and Southeast Asian cuisine: indigenous technology processes, nutrient composition, and cultural significance

The cleaner production of biomass into value-added products via microbial processes adds uniqueness in terms of food quality. The microbe-mediated traditional process for transforming biomass into food is a sustainable practice in Asian food industries. The 18 fermented fish products derived through this process as well as the associated micro-flora and nutritional composition have been focused. This review aims to update the process of green conversion biomass into value-added food products for a more sustainable future. Fish products are classified based on the substrate and source of the enzymes used in fermentation, which includes the three types of technology processing discussed. According to the findings, these fermented fish contain a plethora of beneficial microbiota, making them a valuable source of probiotics that may confer nutritional and health benefits.Bacillus(12 products),Lactobacillus(12 products),Micrococcus(9 products), andStaphylococcus(9 products) were the most common bacterial genera found in 18 fermented fish products. Consuming fermented fish products is beneficial to human health due to their high levels of carbohydrate, protein, fat, and lactic acid. However, biogenic amines, which are produced by certain bacteria as a by-product of their catabolic activity, are a significant potential hazard in traditionally fermented fish.

Fermented fish products in South and Southeast Asian cuisine: indigenous technology processes, nutrient composition, and cultural significance

The cleaner production of biomass into value-added products via microbial processes adds uniqueness in terms of food quality. The microbe-mediated traditional process for transforming biomass into food is a sustainable practice in Asian food industries. The 18 fermented fish products derived through this process as well as the associated micro-flora and nutritional composition have been focused. This review aims to update the process of green conversion biomass into value-added food products for a more sustainable future. Fish products are classified based on the substrate and source of the enzymes used in fermentation, which includes the three types of technology processing discussed. According to the findings, these fermented fish contain a plethora of beneficial microbiota, making them a valuable source of probiotics that may confer nutritional and health benefits. Bacillus (12 products), Lactobacillus (12 products), Micrococcus (9 products), and Staphylococcus (9 products) were the most common bacterial genera found in 18 fermented fish products. Consuming fermented fish products is beneficial to human health due to their high levels of carbohydrate, protein, fat, and lactic acid. However, biogenic amines, which are produced by certain bacteria as a by-product of their catabolic activity, are a significant potential hazard in traditionally fermented fish.

High-throughput sequence analysis of bacterial communities and their predictive functionalities in traditionally preserved fish products of Sikkim, India

Traditionally preserved fish products viz. suka ko maccha, a smoked fish product, sidra and sukuti, sun-dried fish products are commonly consumed in Sikkim state in India. Bacterial communities in these fish products were analysed by high-throughput sequence (HTS) method supported by bioinformatics tool. Metataxonomic of the overall bacterial communities in samples revealed the abundance of phylum Firmicutes followed by Proteobacteria. Psychrobacter was abundant genus in all traditionally preserved fish products of Sikkim, followed by Bacillus, Staphylococcus, Serratia, Clostridium, Enterobacter, Pseudomonas, Rummeliibacillus, Enterococcus, Photobacterium, Myroides, Peptostreptococcus, Plesiomonas and Achromobacter. Product-wise distribution showed that Bacillus was abundant in suka ko maacha and sidra samples, whereas Psychrobacter was abundant in sukuti samples. Unique genus to each product was observed on the basis of analysis of shared operational-taxonomic-unit (OTU) contents, Alpha diversity indices showed significantly differences among the samples, and also showed maximum coverage as per Good's coverage (0.99). Beta diversity showed clustering of bacterial compositions between suka ko maacha and sidra, whereas sukuti showed scattering pattern among the other samples, indicating a diverse population in suka ko maacha and sidra samples. Non-parametric analysis of abundant genera and predictive functionalities showed the complex bacterial inter-dependencies with predictive functionalities mostly in metabolism (79.88%).

Biogenic Amine Contents and Microbial Characteristics of Cambodian Fermented Foods

Naturally fermented foods are an important part of the typical diet in Cambodia. However, the food safety status of these products has not been widely studied. The aim of this study was, therefore, to provide an overview of the quality of these foods in relation to microbiology and biogenic amines. Additionally, the obtained results were compared to the habits and practices of Cambodians in handling this type of food. A total of 57 fermented foods (42 fishery and 15 vegetable products) were collected from different retail markets in the capital of Cambodia. Pathogenic Salmonella spp., Listeria spp., and Listeria monocytogenes were not detected in 25 g samples. Generally, less than 102 cfu/g of Staphylococcus aureus, Escherichia coli, Pseudomonas spp., Enterobacteriaceae, and molds were present in the fermented foods. Bacillus cereus group members (<102 to 2.3 × 104 cfu/g), lactic acid bacteria (<102 to 1.1 × 107 cfu/g), halophilic and halotolerant bacteria (<102 to 8.9 × 106 cfu/g), sulfite-reducing Clostridium spp. (<102 to 3.5 × 106 cfu/g), and yeasts (<102 to 1.1 × 106 cfu/g) were detected in this study. Still, the presence of pathogenic and spoilage microorganisms in these fermented foods was within the acceptable ranges. Putrescine, cadaverine, tyramine, and histamine were detected in 100%, 89%, 81%, and 75% of the tested products, respectively. The concentrations of histamine (>500 ppm) and tyramine (>600 ppm) were higher than the recommended maximum levels in respectively four and one of 57 fermented foods, which represents a potential health risk. The results suggest that the production process, distribution, and domestic handling of fermented foods should be re-evaluated. Further research is needed for the establishment of applicable preservation techniques in Cambodia.