-
Frontiers in Microbiology 2022Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine...
Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O, 30% CO, red and white meats) and oxygen-free MAP (70% N, 30% CO, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of and was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for . Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for . Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose ( or glycogen ( appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit , heavily reduce growth , and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.
PubMed: 35722325
DOI: 10.3389/fmicb.2022.866629 -
Heliyon Nov 2023is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes...
is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes occurring during the process. In this small-scale industrial study, fresh and frozen shark meat was fermented for eight and seven weeks, respectively, and then dried for five weeks. During the fermentation, trimethylamine -oxide levels decreased to below the limit of detection within five weeks and pH increased from about 6 to 9. Simultaneously, trimethylamine and dimethylamine levels increased significantly. Total viable plate counts, and specific spoilage organisms increased during the first weeks of the fermentation period but decreased during drying. Culture-independent analyses (16S rRNA) revealed gradual shifts in the bacterial community structure as fermentation progressed, dividing the fermentation process into three distinct phases but stayed rather similar throughout the drying process. During the first three weeks of fermentation, was dominant in the fresh group, compared to in the frozen group. However, as the fermentation progressed, the groups became more alike with , and being dominant. The PCA analysis done on the chemical variables and 16S rRNA analysis variables confirmed the correlation between high concentrations of TMAO and and at the initial fermentation phase. During the final fermentation phase, correlation was detected between high concentrations of TMA/DMA and , and . The results indicate the possibility to shortening the fermentation period and it is suggested that the microbial community can potentially be standardized with starter cultures to gain an optimal fermentation procedure.
PubMed: 38074871
DOI: 10.1016/j.heliyon.2023.e22127 -
Foods (Basel, Switzerland) Jul 2023The aim of this study was to investigate the microbial and physico-chemical characteristics of cold smoked sea bass (CSSB), a novel italian fish product. The...
The aim of this study was to investigate the microbial and physico-chemical characteristics of cold smoked sea bass (CSSB), a novel italian fish product. The microbiological analyses showed the presence of bacterial contamination from the raw material, the environment, and the production process. The microbial spoilage population was dominated by lactic acid bacteria (LAB) associated with Gram-negative fermenting bacteria, including and psychrotrophic Enterobacteriaceae. and spp. were also present; in contrast, mould and yeast were not detected (<2 CFU/g). High levels (6-7 log CFU/g) of LAB and total bacteria count (TBC) were observed from day 45 of storage; however, their presence does not seem to have influenced the total volatile basic nitrogen (TVB-N), which always remained below 35 mg N/100 g. Consequently, the product is acceptable until day 60 of storage, considering that the malonaldehyde index (TBARS) was lower than 6.5 nmol/g. Pathogenic bacteria such as spp. and were not detected. Currently, there is a growing demand for seafood due to its high quality and nutritional value. Cold smoked sea bass offers a source of macro- and micronutrients essential for the proper functioning of the human body. It is also rich in protein and omega-3 fatty acids. The WHO and FAO evaluated the benefits and risks and concluded that there is convincing evidence of health benefits from fish consumption, such as a reduction in the risk of heart failure and improved neurodevelopment in infants and young children when fish is consumed by the mother before and during pregnancy. The CSSB analysed in this study demonstrated to have health benefits due to long-chain omega-3 PUFAs and other nutrients, such as proteins, minerals, and vitamin D, which are sometimes difficult to obtain from other sources. The results show that CSSB has a high nutritional value and excellent microbial quality.
PubMed: 37509776
DOI: 10.3390/foods12142685 -
Biology Dec 2023Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and...
Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and anti-pathogen capabilities under salinity stress. In this study, 16s amplicon and transcriptome sequencing were used to analyze the intestine of under low-salinity stress (15 ppt). This study aimed to investigate the response mechanisms of the intestinal microbiota and gene expression to acute low-salinity stress. The intestinal tissues of were analyzed using 16S microbiota and transcriptome sequencing. The microbiota analysis demonstrated that the relative abundances of and decreased significantly, whereas , , , , , , , and became the predominant communities. Transcriptome sequencing identified numerous differentially expressed genes (DEGs). The DEGs were clustered into many Gene Ontology terms and further enriched in some immunity- or metabolism-related Kyoto Encyclopedia of Genes and Genomes pathways, including various types of N-glycan biosynthesis, amino acid sugar and nucleotide sugar metabolism, and lysosome and fatty acid metabolism. Correlation analysis between microbiota and DEGs showed that changes in , , , and were positively correlated with immune-related genes such as peritrophin-1-like and mucin-2-like, and negatively correlated with caspase-1-like genes. Low-salinity stress caused changes in intestinal microorganisms and their gene expression, with a close correlation between them.
PubMed: 38132328
DOI: 10.3390/biology12121502 -
Foods (Basel, Switzerland) Dec 2023Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause...
Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause fatal listeriosis infections. Another challenge and potential risk associated with CS salmon is their high levels of sodium salt. Excess dietary intake is associated with serious health complications. In the present study, anti-listerial bacteriocin (nisin), P100 bacteriophages (Phageguard L, PGL) and fermentates (Verdad N6, P-NDV) were evaluated as commercial bio-preservation strategies for increased control of in standard (with NaCl) and sodium-reduced (NaCl partially replaced with KCl) CS salmon. Treatments of CS salmon with nisin (1 ppm) and PGL (5 × 10 pfu/cm) separately yielded significant initial reductions in (up to 0.7 log) compared to untreated samples. Enhanced additive reductions were achieved through the combined treatments of nisin and PGL. Fermentates in the CS salmon inhibited the growth of Listeria but did not lead to its eradication. The lowest levels of during storage were observed in nisin- and PGL-treated CS salmon containing preservative fermentates and stored at 4 °C, while enhanced growth was observed during storage at an abusive temperature of 8 °C. Evaluation of industry-processed standard and sodium-replaced CS salmon confirmed significant effects with up to 1.7 log reductions in levels after 34 days of storage of PGL- and nisin-treated CS salmon-containing fermentates. No differences in total aerobic plate counts were observed between treated (PGL and nisin) or non-treated standard and sodium-reduced CS salmon at the end of storage. The microbiota was dominated by but with a shift showing dominance of spp. and spp. in fermentate-containing samples. Similar and robust reductions in can be achieved in both standard and sodium-replaced CS salmon using the bio-preservation strategies of nisin, PGL and fermentates under various and relevant processing and storage conditions.
PubMed: 38137194
DOI: 10.3390/foods12244391 -
Marine Environmental Research Apr 2024The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel...
Interactive effects of elevated temperature and Photobacterium swingsii infection on the survival and immune response of marine mussels (Perna canaliculus): A summer mortality scenario.
The New Zealand Greenshell™ mussel (Perna canaliculus) is an economically important aquaculture species. Prolonged increases in seawater temperature above mussel thermotolerance ranges pose a significant threat to mussel survival and health, potentially increasing susceptibility to bacterial infections. Using challenge experiments, this study examined the combined effects of increased seawater temperature and bacterial (Photobacterium swingsii) infection on animal survival, haemocyte and biochemical responses of adult mussels. Mussels maintained at three temperatures (16, 20 and 24 °C) for seven days were either not injected (control), injected with sterile marine broth (injection control) or P. swingsii (challenged with medium and high doses) and monitored daily for five days. Haemolymph and tissue samples were collected at 24, 48, 72, 96, 120 h post-challenge and analysed to quantify bacterial colonies, haemocyte responses and biochemical responses. Mussels infected with P. swingsii exhibited mortalities at 20 and 24 °C, likely due to a compromised immune system, but no mortalities were observed when temperature was the only stressor. Bacterial colony counts in haemolymph decreased over time, suggesting bacterial clearance followed by the activation of immune signalling pathways. Total haemocyte counts and viability data supports haemocyte defence functions being stimulated in the presence of high pathogen loads at 24 °C. In the gill tissue, oxidative stress responses, measured as total antioxidant capacity and malondialdehyde (MDA) levels, were higher in infected mussels (compared to the controls) after 24h and 120h post-challenge at the lowest (16 °C) and highest temperatures (24 °C), indicating the presence of oxidative stress due to temperature and pathogen stressors. Overall, this work confirms that Photobacterium swingsii is pathogenic to P. canaliculus and indicates that mussels may be more vulnerable to bacterial pathogens under conditions of elevated temperature, such as those predicted under future climate change scenarios.
Topics: Animals; Temperature; Perna; Photobacterium; Immunity
PubMed: 38364448
DOI: 10.1016/j.marenvres.2024.106392 -
Animal Nutrition (Zhongguo Xu Mu Shou... Jun 2022The utilization efficiency of soy protein is affected by its 2 anti-nutritional substances-the antigens β-conglycinin and glycinin. This study investigated their...
The utilization efficiency of soy protein is affected by its 2 anti-nutritional substances-the antigens β-conglycinin and glycinin. This study investigated their effects on the growth performance, intestinal immune defense, and microbiome in juvenile pearl gentian groupers (♀ × ♂). Three isonitrogenous and isolipidic diets were formulated containing fishmeal supplemented with 70 g/kg β-conglycinin or 100 g/kg glycinin, or no supplementation (control). Each experimental diet was fed to quadruplicate groups with 30 fish in each tank for 8 weeks. Dietary inclusion of either β-conglycinin or glycinin significantly reduced weight gain and specific growth rates, and cell proliferation of the distal intestine. Histological evaluation of the intestine tract revealed the inflammation signs, characterized by reducing of plica height and width as well as the number of the goblet cells, and widening of the lamina propria. The group fed the β-conglycinin diet had reduced lysozyme activity, contents of immunoglobulin M and complements 3 and 4. Increased activities of caspase-3 and -9 were observed in the group fed the β-conglycinin diet compared to the other 2 groups. In the intestinal microbiota, the relative abundances of the potentially pathogenic genera and were significantly higher in the glycinin group than those in others. Therefore, the existence of soybean antigens (β-conglycinin or glycinin) could damage the structural integrity of the intestine, reduce immune defense, reshape the intestinal microbiome and, ultimately, impair growth in fish.
PubMed: 35600546
DOI: 10.1016/j.aninu.2021.11.001 -
PeerJ 2020Fish skin and gut microbiomes contribute to host health and growth and are often significantly different in aquaculture-reared fish compared to wild fish. Determining...
Fish skin and gut microbiomes contribute to host health and growth and are often significantly different in aquaculture-reared fish compared to wild fish. Determining how factors associated with aquaculture, including altered diet and abiotic conditions, affect the microbiome will assist with optimizing farming practices and non-invasively assessing fish health. Here, juvenile yellowtail kingfish () housed at optimal (22 °C) and non-optimal (26 °C) water temperature were fed a fishmeal control diet or the same diet substituted with 30% soy-protein concentrate (SPC) in order to investigate impacts on host health and the microbial community composition of the skin mucosa, gut mucosa and digesta. Each of these sites was observed to have a distinct microbiome composition. The combination of SPC and housing at 26 °C significantly reduced weight gain in yellowtail kingfish and affected immune parameters. The overall microbial composition and relative abundance of specific operational taxonomic units (OTUs) was also significantly altered by inclusion of SPC at 26 °C, with a notable increase in an OTU identified as Photobacterium in the skin mucosa and digesta. Increased relative abundance of sp. was significantly correlated with reduced levels of digesta myeloperoxidase in yellowtail kingfish; a recognized innate immunity defense mechanism. The changes in the microbial communities of yellowtail kingfish fed a diet containing 30% SPC at 26 °C highlights the importance of considering the interactive effects of diet and environmental factors on microbiome health in farmed yellowtail kingfish.
PubMed: 32219022
DOI: 10.7717/peerj.8705 -
Microorganisms Jun 2022Histamine is a toxic biogenic amine commonly found in seafood products or their derivatives. This metabolite is produced by histamine-producing bacteria (HPB) such as ,... (Review)
Review
Histamine is a toxic biogenic amine commonly found in seafood products or their derivatives. This metabolite is produced by histamine-producing bacteria (HPB) such as , , , , , , , , spp., , , , , , , , , , spp., , , , , , and In this review, the role of these bacteria in histamine production in fish and seafood products with consequences for human food poisoning following consumption are discussed. In addition, methods to control their activity in countering histamine production are proposed.
PubMed: 35744715
DOI: 10.3390/microorganisms10061197 -
Ecotoxicology and Environmental Safety Dec 2021Hundreds of tons of antibiotics are widely used in aquaculture to prevent microbial infections and promote fish growth. However, the overuse of antibiotics and chemical...
Hundreds of tons of antibiotics are widely used in aquaculture to prevent microbial infections and promote fish growth. However, the overuse of antibiotics and chemical products can lead to the selection and spreading of antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), which are of great concern considering the threat to public health worldwide. Here, in-depth metagenome sequencing was performed to explore the environmental resistome and ARB distribution across farming stages in shrimp farms and examine anthropogenic effects in nearby coastal waters. A genome-centric analysis using a metagenome binning approach allowed us to accurately investigate the distribution of pathogens and ARG hosts in shrimp farms. The diversity of resistomes was higher in shrimp farms than in coastal waters, and the distribution of resistomes was dependent on the farming stage. In particular, the tetracycline resistance gene was found mainly at the early post-larval stage regardless of the farm. The metagenome-assembled genomes of Vibrio spp. were dominant at this stage and harbored tet34, which is known to confer resistance to oxytetracycline. In addition, opportunistic pathogens such as Francisella, Mycoplasma, Photobacterium, and Vibrio were found in abundance in shrimp farms, which had multiple virulence factors. This study highlights the increased resistance diversity and environmental selection of pathogens in shrimp farms. The use of environmental pollutants on farms may cause an increase in resistome diversity/abundance and the transmission of pathogens to the surrounding environment, which may pose future risks to public health and aquatic organisms.
Topics: Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors; Animals; Anti-Bacterial Agents; Aquaculture; Farms; Genes, Bacterial; Republic of Korea
PubMed: 34653940
DOI: 10.1016/j.ecoenv.2021.112858