Fermented Fish Products: Balancing Tradition and Innovation for Improved Quality.

The flavor profile of fermented fish products is influenced by the complex interplay of microbial and enzymatic actions on the raw materials. This review summarizes the various factors contributing to the unique taste and aroma of these traditional foods. Key ingredients include locally sourced fish species and a variety of spices and seasonings that enhance flavor while serving as cultural markers. Starter cultures also play a critical role in standardizing quality and accelerating fermentation. Flavor compounds in fermented fish are primarily derived from the metabolism of carbohydrates, lipids, and proteins, producing a diverse array of free amino acids, peptides, and volatile compounds such as aldehydes, ketones, alcohols, and esters. The fermentation process can be shortened by certain methods to reduce production time and costs, allowing for faster product turnover and increased profitability in the fermented fish market. Fermented fish products also show potent beneficial effects. This review highlights the importance of integrating traditional practices with modern scientific approaches. Future research directions to enhance the quality of fermented fish products are suggested.

Removal of Histamine from Fish Sauce by Staphylococcus debuckii sp. Isolated from Fermented Fish.

Research background: One of the issues in the production of fish sauce is the legal constraints on the concentration of histamine produced by bacteria during fermentation because it causes allergic reactions in humans. The goal of this study is therefore to eliminate histamine from the final product after fermentation to enhance the quality of fish sauce for consumer safety, manufacturer exportability and domestic sales. Experimental approach: The bacteria that grow in the histamine medium were isolated from the salted fish. Their ability to degrade histamine in the media with high NaCl content was tested. The bacterium with the highest histamine-degrading ability was identified and the histamine-degrading conditions were optimized, including the incubation temperature and the amount of NaCl in the medium. The regression equation was generated and tested using the local fish sauce in which different concentrations of histamine were added. Results and conclusions: Among the five bacteria isolated from the salted fish, the isolate with the greatest ability to degrade histamine was identified as Staphylococcus debuckii sp. The study of the capacity of the isolated bacteria to degrade histamine using the synthetic histamine broth (pH=7.0, t=25 °C and NaCl 25 % (m/V)) indicated that they were able to degrade up to 56 % of histamine. The optimization analysis showed that increasing the pH of the medium to 7.5 and lowering the incubation temperature to 20 °C could improve the histamine removal from 56 to 73 %. The generated regression model, validated by the experimental results of histamine removal from fish sauce, showed an acceptable error (not more than 10 %). S. debuckii, the isolated histamine-degrading bacteria, could be used as an inoculum to reduce histamine accumulated in fish products. Novelty and scientific contribution: The microbiological technique developed here can decrease the histamine concentration in the final product, fish sauce, to improve its quality in terms of food safety and satisfy the histamine regulation requirement. The findings of this study can also be used to treat other liquid foods that contain high concentrations of histamine.

Flavor Formation in Dry-Cured Fish: Regulation by Microbial Communities and Endogenous Enzymes.

Dried salted fish is a traditional dry-cured fish that is sprinkled with salt before the curing process. With a unique flavor as well as diverse varieties, dry-cured fish is popular among consumers worldwide. The presence of various microbial communities during the curing process leads to numerous metabolic reactions, especially lipid oxidation and protein degradation, which influence the formation of flavor substances. However, during industrial curing, the quality of dry-cured fish is difficult to control, leading to the formation of products with diverse flavors. This review describes the curing process of dried salted fish, the key microorganisms involved in the curing process of typical dried salted fish products at home and abroad, and the correlation between biological metabolism and flavor formation and the underlying mechanism. This review also investigates the prospects of dried salted fish products, proposing methods for the analysis of improved curing processes and the mechanisms of dried salted fish. Through a comprehensive understanding of this review, modern production challenges can be addressed to achieve greater control of microbial growth in the system and improved product safety. In addition to advancing our understanding of the processes by which volatile flavor compounds are formed in conventional dry-cured fish products, we expect that this work will also offer a theoretical framework for enhancing their flavor in food processing.

Risk Factors Associated with Nasopharyngeal Cancer Incidences in Indonesia: A Systematic Review and Meta-Analysis.

OBJECTIVE: To determine the risk factors associated the incidence of NPC, particularly in Indonesia. METHODS: This systematic review and meta-analysis was conducted according to PRISMA statement. Database including PubMed, Scopus, Science Direct, Web of Science, and GARUDA were retrieved. Newcastle-Ottawa scale was used to assess the quality of published study and analyse the risk of bias of included study. Random-effect model and reported pooled Odds Ratio (OR) with 95%CI was carried out in our meta-analysis. RESULTS: A pooled of 7 studies were included in our study which included 764 participants. We found that female gender was not associated with the incidences of NPC (OR 1.45, 95% CI: 0.61-3.45, p=0.40), and smoking was highly increased the incidence of NPC (OR 4.39 95% CI (0.79-24.40), but not statistically significant (p=0.09). Furthermore, salted fish consumption and some HLA alleles were associated with increased risk. CONCLUSION: The incidence of NPC is not associated with female gender nor smoking habits. However, the risk of NPC is higher for those who consume salted fish and have some susceptible HLA alleles. Further investigations in larger studies are needed to confirm these findings.

Factors affecting bacterial community dynamics and volatile metabolite profiles of Thai traditional salt fermented fish.

Bacterial diversity of the Thai traditional salt fermented fish with roasted rice bran (Pla-ra) was investigated using classical and molecular approaches. Bacterial population of Pla-ra ranged from 102-106 in solid-state (SSF) and 106-109 CFU/g in submerged (SMF) fermentation types. Halanaerobium spp. and Lentibacillus spp. were the main genera particularly detected when rRNA analysis was applied. Tetragenococcus halophillus were dominant during the final stage in sea salt-recipe samples while Bacillus spp. were found in those rock salt recipes. In contrast, cultural plating demonstrated that Bacillus spp., generally B. amyloliquefaciens, were the dominant genera. In addition, B. pumilus, B. autrophaeus, B.subtilis and B. velezensis shown some relations with rock salt-recipe samples. The main volatile metabolites in all samples were butanoic acid and its derivatives. Key factors affected bacterial profiles and volatile compounds of salt fermented fish were type of salt, addition of roasted rice bran, and fermenting conditions.

Heavy metal contents in salted fish retailed in Egypt: Dietary intakes and health risk assessment.

Background: In Egypt, salted fish is considered a typically processed fish, including salted sardine, salted mullet (feseikh), keeled mullet (sahlia), and herrings. High-quality protein, polyunsaturated fatty acids, vital amino acids, and trace minerals such as magnesium and calcium are all abundant in fish. However, eating salted fish can expose people to toxins found in the environment, such as heavy metals. Aim: In Zagazig, Egypt, four types of locally produced salted fish-salted sardine, feseikh, sahlia, and herrings-were tested for heavy metals, specifically lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). Second, the assessed heavy metals linked to the Egyptian population's consumption of salted fish were used to calculate estimated daily intakes (EDIs) and potential health hazards, such as hazard quotient (HQ) and hazard index (HI). Methods: Samples of salted herrings, feseikh, sahlia, and sardines were gathered from the markets in Zagazig. Samples of salted fish were subjected to acid digestion and then heavy metal extraction. Atomic absorption spectrometers (AAS) were used to measure heavy metals. HI, HQ, and EDI were computed computationally. Results: With the exception of mercury, which was not found in the salted herrings, the recorded results showed that all of the tested metals were present in the samples that were evaluated. The herrings contained residual Pb and Cd contents that were highest, followed by sardine, feseikh, and sahlia, in that order. After sardine, herrings, and sahlia, feseikh has the greatest concentration. Sardine, feseikh, and sahlia had the highest quantities of mercury, in that order. A number of samples were found to be above the maximum allowable levels. There were no apparent hazards associated with consuming such conventional fish products, according to the computed HQ and HI values for the heavy metals under investigation based on the daily intakes. Conclusion: Samples of salted fish sold in Zagazig, Egypt, had high quantities of the hazardous elements Pb, Cd, As, and Hg. Due to the bioaccumulation and biomagnification characteristics of these studied metals, such data should be taken carefully even though the computed health hazards revealed no potential problems.

Prevalence of Histamine-Forming Bacteria in Two Kinds of Salted Fish at Town Markets of Guangdong Province of South China.

ABSTRACT: Histamine-forming bacteria (HFB) were isolated from the 70 salted fish samples bought from town markets of Guangdong Province of south China. In addition, the histamine-forming ability of HFB was analyzed. There were 31 strains of HFB isolated from 36 salted fish pickled overnight. They were identified as six bacteria species: Vibrio alginolyticus, Vibrio rumoiensis, Staphylococcus saprophyticus, Staphylococcus xylosus, Lactococcus lactis, and Morganella morganii. The rate of confirmation of V. alginolyticus was highest (23 of 31), exceeding 200 mg/kg histamine. In particular, M. morganii produced a histamine amount that exceeded 2,000 mg/kg, although it was only one isolate in this study. In addition, five bacteria species of HFB were isolated from 34 dried salted fish. Among them, S. saprophyticus was dominant in the dried salted fish but produced histamines below 200 mg/kg. However, Enterobacter aerogenes from dried salted fish formed a histamine amount exceeding 200 mg/kg. The study showed that the dominant strain of HFB was different in two kinds of salted fish. Both kinds of salted fish contained HFB whose histamine-forming capacity exceeded 200 mg/kg. As a result, the safety of salted fish should be of concern, especially salted fish pickled overnight.

Salted fish and processed foods intake and nasopharyngeal carcinoma risk: a dose-response meta-analysis of observational studies.

PURPOSE: This study aims to analyze whether the consumption of salted fish and processed foods increases the risk of nasopharyngeal carcinoma by analyzing the relevant case-control or cohort design. METHODS: Major databases such as PubMed, ScienceDirect, Embase and Cochrane Library were searched to conduct related studies. In addition, Newcastle-Ottawa scale was employed for assessing the quality of articles. Random-effect model was utilized for meta-analysis. Total relative risk (RR) and 95% confidence interval (95% CI) were calculated. RESULTS: Dose response showed a consistent linear relationship between the intake of salted fish and processed foods and the risk of nasopharyngeal carcinoma. In salted fish, the summary RR was 1.23 (1.04-1.47) for low intake and 1.45 (1.19-1.76) for high intake. For processed meat, low intake was 1.33 (1.09-1.62) and high intake was 1.65 (1.35-2.02). Low intake of processed vegetables was 1.28 (1.05-1.55) and high intake was 1.45 (1.17 -1.79) for high intake. Significant heterogeneity existed in all data but decreased in some subgroups after subgroup analysis. CONCLUSION: Salted fish and processed foods are risk factors for increasing nasopharyngeal carcinoma, but they have different risk characteristics due to different intakes, different stages, and different types.

An Outbreak of Botulinum Types A, B, and E Associated With Vacuum-Packaged Salted Fish and Ham.

BACKGROUND: Botulinum toxin is a neurotoxin generated during the growth of Clostridium botulinum and can lead to a rare but life-threatening disease with neurologic symptoms. Relatively little is known about the many types of botulinum toxins in China. The clinical symptoms of the different types of botulism toxin-induced illnesses appear after an incubation period and vary greatly by the serotype and degree of exposure to the toxin. CASE REPORT: We describe 4 patients who consumed vacuum-packaged salted fish and ham and then presented with severe gastrointestinal symptoms, resulting in vomiting and one death. Blood serum and urine samples tested by the botulinum neurotoxin Endopep-MS assay were positive for botulinum toxin types A, B, and E. The patient who consumed the largest amount of fish and ham died after 36 h, and the other patients were treated with botulism antitoxin after being diagnosed with a botulinum toxin-induced illness and recovered after 1 month. These cases illustrate the importance of early diagnosis and early treatment of botulism type E, in particular, because of the risk of respiratory failure and treatment delays, which can result in increased mortality and poorer overall outcomes. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Our cases illustrate the importance of early diagnosis and especially the treatment of illnesses related to botulism type E because of the risk of respiratory failure and because treatment delays can result in increased mortality and worsened overall outcomes.

Pickled Vegetable and Salted Fish Intake and the Risk of Gastric Cancer: Two Prospective Cohort Studies and a Meta-Analysis.

An increased risk of gastric cancer for pickled vegetable and salted fish intake has been suggested, yet the lack of a dose-response association warrants a quantitative analysis. We conducted a meta-analysis, combining results from our analysis of two large Korean cohort studies and those from previous prospective cohort studies. We investigated the association of pickled vegetable and salted fish intake with gastric cancer in the Korean Genome Epidemiology Study and the Korean Multi-center Cancer Cohort Study using Cox proportional hazard models. We then searched for observational studies published until November 2019 and conducted both dose-response and categorical meta-analyses. The pooled relative risk (RR) of gastric cancer incidence was 1.15 (95% Confidence Interval (CI), 1.07-1.23) for 40 g/day increment in pickled vegetable intake in a dose-response manner (P for nonlinearity = 0.11). As for salted fish intake, the pooled risk of gastric cancer incidence was 1.17 (95% CI, 0.99-1.38) times higher, comparing the highest to the lowest intake. Our findings supported the evidence that high intake of pickled vegetable and salted fish is associated with elevated risk of gastric cancer incidence.

Nasopharyngeal Carcinoma (NPC) Risk Factors: A Systematic Review and Meta-Analysis of the Association with Lifestyle, Diets, Socioeconomic and Sociodemographic in Asian Region.

OBJECTIVE: Risk factors of nasopharyngeal carcinoma (NPC) have been linked with diets, life style and viral
infections. NPC is more rampant in Asian populations than non-Asian countries. Our study aims to assess the validity
of the suggestions provided by multiple case control studies demonstrating that salted fish consumption, smoking and
alcohol consumption are associated with the risk of NPC in Asia. METHODS: Search for related literature on salted fish,
smoking and alcohol consumption were performed via Science Direct, PubMed databases and Google Scholar. Articles
included in this study were from 2009 to 2017, with specific focus on salted fish, smoking and alcohol consumption
as risk factors of NPC. This study excluded all articles published prior to 2009 and articles involving other cancers.
Data were extracted independently by two different researchers and harmonized. Meta-analysis was conducted on the
obtained data, by using R package Meta to create funnel and forest plots. RESULTS: The meta-analysis revealed that
salted fish, smoking and alcohol consumption were significantly associated to NPC risk with random effect model score
showing OR of 1.41 at 95% confidence interval (CI) of 1.13-1.75 (P<0.01), OR of 1.89 at 95 % CI of 1.49 - 2.38, and
OR: 1.42 at 95 % CI of 1.23 - 1.65 respectively. Our results also revealed significant association of salted meat, salted
vegetables, house type, wood dust exposure associated with NPC risk with p values less than 0.05. CONCLUSION: This
study proposes that salted fish intake, smoking and alcohol consumption might be linked to NPC risk in Asians. Further
studies are necessary to ascertain the molecular mechanisms and clarify if the associated path that could function as
therapeutic target.

Past and Recent Salted Fish and Preserved Food Intakes Are Weakly Associated with Nasopharyngeal Carcinoma Risk in Adults in Southern China.

BACKGROUND: Chinese-style salted fish intake in early life is considered an established risk factor for nasopharyngeal carcinoma (NPC). However, results for adult intakes of salted fish and preserved foods are inconsistent. OBJECTIVE: The aim of this study was to ascertain the relations of Chinese-style hard and soft salted fish and preserved food intakes with NPC risk. METHODS: We conducted a population-based case-control study in southern China with 2554 NPC cases identified through a rapid case ascertainment system and 2648 healthy controls, frequency-matched on age, sex, and area. Subjects (aged 20-74 y) were interviewed via a food-frequency questionnaire, including information on portion size. Data were also collected on alcohol consumption and potential confounders. Food intake was grouped into 3-5 energy-adjusted intake levels during adulthood (10 y prior) and adolescence (16-18 y). For childhood (at age 10 y), intake frequency of selected food items was collected. Multivariate-adjusted ORs with 95% CIs were estimated via logistic regression. RESULTS: We found no association between NPC and intake of hard Chinese-style salted fish during adulthood, and an increased risk at the highest level of intake during adolescence (OR: 1.19; 95% CI: 1.03, 1.39). In contrast, we found a decreased risk for the middle intake level of soft salted fish during adulthood (OR: 0.68; 95% CI: 0.57, 0.81) and adolescence (OR: 0.71; 95% CI: 0.59, 0.85). Preserved foods showed contrasting risk profiles, e.g., the highest adult intake level of salted egg (OR: 1.51; 95% CI: 1.22, 1.87) and fermented black beans (OR: 0.67; 95% CI: 0.56, 0.80). Associations with NPC were weaker than previously reported, e.g., for weekly childhood intake of salted fish (OR: 1.56; 95% CI: 1.24, 1.97). CONCLUSIONS: Hard and soft salted fish have different risk profiles. Salted fish and other preserved foods were at most weak risk factors for NPC in all periods and may play a smaller role in NPC occurrence than previously thought.

Factors Related to the Presence of Formaldehyde in the Salted Fish Trade in Ciputat, Indonesia

Abstract@#Introduction: The use of formaldehyde in salted fish as a food preservative is prohibited and against the law. Salted fish is food that in demand in many Indonesian cuisine. The purpose of this study is to determine the relationship between education, knowledge, attitude and duration of work selling salted fish with the exixtence of formaldehyde in salted fish products. Methods: A quantitative cross-sectional study. Data collection by interviews 11 sellers and testing 72 salted fish samples. Tests were carried out using colourimetric test of formaldehyde and interviews sellers in a traditional Market Ciputat, Banten Indonesia in 2018. Results: The results of this study were from 72 laboratory samples of salted fish, 42 positive containing formaldehyde, most of them were Anchovy Stolephorus tri (21.9%) and delivered from several places in Indonesia. Based on Fisher exact tests showed that there were no relationship(p-value> 1.000) between education, knowledge, perception ,and attitudes of sellers using formaldehyde and Man-Whitney tes determined there was no difference in the duration of works between sellers who use and who do not use formaldehyde (p-value 0.301). Conclusions: The highest percentage of carcinogenic formaldehyde in salted fish is crucial. Public health sector should pay more attention and the government should run inspection and health promotion regularly.

Activities of Endogenous Lipase and Lipolysis Oxidation of Low-Salt Lactic Acid-Fermented Fish (Decapterus maruadsi).

There is increasing demand for low-salt meat products that retain traditional flavors. In this study, dry-salted fish (Decapterus maruadsi) were processed by 2 methods to obtain traditional salted fish (HS) and low-salt lactic acid-fermented fish (LAF). The relationship between lipolysis and lipid oxidation was investigated by evaluating changes in endogenous lipase (lipolytic enzymes; lipoxygenase, LOX), free fatty acid composition, thiobarbituric acid reactive substances (TBARS), and peroxide value (POV) during processing. Lipolytic enzyme activity showed a decreasing trend, in general. LOX activity initially increased and eventually decreased. Phospholipase, acid lipase, and neutral lipase activity was 0.33, 0.17, 0.57 (in HS) and 0.39, 0.25, 0.67 (in LAF) times in the final product than the activity levels observed in fresh fish. A principal component analysis indicated that phospholipase and neutral lipase play major roles in promoting lipid hydrolysis (in HS and LAF), the correlation between lipolytic activity and lipid oxidation in HS is greater than the correlation in LAF, and the contribution of LOX to lipid oxidation was minor in salted fish.

Mold Contamination and aflatoxin B1 levels in salted fish commodities from traditional market in Yogyakarta and Surabaya, Indonesia

Aims@#To identify mold contaminant on salted fish, from two different market locations (Kenjeran market, Surabaya and Beringharjo market, Yogyakarta). Furthermore, levels of AFB1 (aflatoxin B1) in salted fish samples were assayed. @*Methodology and results@#The samples were cultivated on DRBC (Dichloran Rose Bengal Chloramphenicol Agar) and DG-18 (Dichloran (18%) Glycerol Agar) medium for enumeration, then transferred on MEA (Malt Extract Agar) medium for isolation and identification, followed by ELISA test to measure the AFB1 level. Meanwhile aflatoxin biosynthesis correlated genes (i.e. aflR, nor-1 and omtB genes) were identified using Polymerase Chain Reaction (PCR) method. The results showed that Aspergillus tamarii and A. flavus being contaminant on salted fish along with A. sydowii, A. niger, A. versicolor, Penicillium citrinum, and P. chrysogenum. Rhizopus sp. contamination was also found. AFB 1 was positively detected in all of samples with the highest concentration measured was 75.81 μg/kg which belong to Lidah salted fish and the lowest concentration measured was 4.33 μg/kg which belong to Rese salted fish. The suspected A. flavus and A. tamarii isolated from salted fish was positively detected in the presence of aflR, nor-1 and omtB genes. @*Conclusion, significance and impact of study@#Mold contamination was detected in salted fish from two different markets and all of those samples were contaminated by AFB1. These can be important information related to food safety aspect for salted fish.

Contamination of Chinese salted fish with volatile N-nitrosamines as determined by QuEChERS and gas chromatography-tandem mass spectrometry.

The QuEChERS sample preparation method and gas chromatography-tandem mass spectrometry were employed to determine nine volatile N-nitrosamines (VNAs) in Chinese salted fish. This method was validated by considering calibration plot linearity, selectivity, matrix effects, trueness, precision, limits of quantification and specificity. Fifty-four samples of Chinese salted fish obtained from five provinces were analyzed. The results indicated that the concentrations of one VNA, N-nitrosodimethylamine in 57.4% of the samples exceeded the acceptable limit (the China national standard value of 4µgkg-1), and total VNA contents in 68.5% of the samples exceeded the acceptable United States Department of Agriculture limit of 10µgkg-1 for cured meats. In addition, total VNAs in marine salted fish that exceeded the acceptable limit were statistically higher than those in freshwater salted fish. The present study suggests that VNA contamination in Chinese salted fish continues to be serious, and deserves stricter management by the authorities.

Histamine Formation in a Dry Salted Twaite Shad ( Alosa fallax lacustris ) Product.

Landlocked shad is a freshwater clupeid fish ( Alosa fallax lacustris ) whose consumption is associated with the risk of scombrotoxin poisoning. Traditionally, fresh shad are subjected to an artisanal processing procedure, consisting of dry salting and maturation under pressure, to give a fish product named missoltino , which is stored in large metallic barrels and is sold to local consumers and restaurants. In recent years, the introduction of modern food packaging technologies has enabled this product to also be distributed in shops and supermarkets. Consequently, the determination of the safety of this product is an urgent issue. The aims of the present research were to measure histamine levels and histamine-forming bacteria in shad products collected at different phases of preparation and ripening, in order to minimize poison hazards, to provide technical information about risk, and to standardize the production process. One hundred twenty-six samples of shad (21 fresh fish and 105 dried) at different phases of preparation and ripening were collected from seven producers and were analyzed for chemical composition, histamine content, and microbiological properties. After 130 days of ripening, samples from three producers presented unacceptable amounts of histamine (>200 mg/kg), according to European Union legislation. A moderate negative correlation was found between histamine levels and salt content (r =-0.504, P < 0.01) and between histamine levels and water phase salt content (r =-0.415, P < 0.01). Several bacterial strains that were positive on Niven's medium were isolated during the early phases of production, whereas the extreme environment of salted shad at the end of ripening led to a drastic decrease of bacteria, but not of histamine. The most effective preventive measures for histamine formation and accumulation in salted shad were strictly related to fish handling and storage conditions during processing.

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

The distribution and characterization of bacteria including lactic acid bacteria (LAB) in the traditional and popular salted fish yegyo ngapi in Myanmar were studied to clarify the contribution of these bacteria to the curing and ripening of this product. Samples of yegyo ngapi purchased from a market in Yangon were used. Most of the isolates obtained using de Man, Rogosa and Sharpe medium containing 10 % NaCl were identified as coccoid LAB on the basis of their basic phenotypic characteristics. From the results of 16S rRNA gene sequencing and PCR-restriction fragment length polymorphism analysis of this gene, most of the isolates were identified as the halophilic LAB Tetragenococcus muriaticus. Analyses of the 16S rRNA gene based on the clone library using DNA extracted from salted fish products were also performed. The results of these molecular-analysis-based techniques showed that spore-forming and non-spore-forming anaerobic bacteria including the genera Clostridium and Halanaerobium in addition to T. muriaticus were also frequently found in bacterial communities. These findings suggest that the anaerobic condition during curing and ripening resulted in bacterial communities composed of strictly anaerobic bacteria and halophilic LAB, and that these bacteria might also contribute to the manufacturing processes of this product. In addition, DNA sequences similar to that of Clostridium botulinum were found in the clone library analysis. Therefore, despite no reports of botulism poisoning from the region where the samples were taken, closer surveillance should be carried out from the viewpoint of food safety.

Reduction of histamine and biogenic amines during salted fish fermentation by Bacillus polymyxa as a starter culture.

Bacillus polymyxa D05-1, isolated from salted fish product and possessing amine degrading activity, was used as a starter culture in salted fish fermentation in this study. Fermentation was held at 35°C for 120 days. The water activity in control samples (without starter culture) and inoculated samples (inoculated with B. polymyxa D05-1) remained constant throughout fermentation, whereas the pH value rose slightly during fermentation. Salt contents in both samples were constant in the range of 17.5-17.8% during the first 60 days of fermentation and thereafter increased slowly. The inoculated samples had considerably lower levels of total volatile basic nitrogen (p < 0.05) than control samples at each sampling time during 120 days of fermentation. Aerobic bacterial counts in inoculated samples were retarded during the first 60 days of fermentation and thereafter increased slowly, whereas those of control samples increased rapidly with increased fermentation time. However, the aerobic bacterial counts of control samples were significantly higher (p < 0.05) than those of inoculated samples after 40 days of fermentation. In general, overall biogenic amine contents (including histamine, putrescine, cadaverine, and tyramine) in the control samples were markedly higher (p < 0.05) than those of the inoculated samples throughout fermentation. After 120 days of fermentation, the histamine and overall biogenic amine contents in the inoculated samples were reduced by 34.0% and 30.0%, respectively, compared to control samples. These results emphasize that the application of starter culture with amines degrading activity in salted fish products was effective in reducing biogenic amine accumulation.

Degradation of histamine by Bacillus polymyxa isolated from salted fish products.

Histamine is the causative agent of scombroid poisoning, a foodborne chemical hazard. Histamine is degraded by the oxidative deamination activity of certain microorganisms. In this study, eight histamine-degrading bacteria isolated from salted fish products were identified as Rummeliibacillus stabekisii (1 isolate), Agrobacterium tumefaciens (1 isolate), Bacillus cereus (2 isolates), Bacillus polymyxa (1 isolate), Bacillus licheniformis (1 isolate), Bacillus amyloliquefaciens (1 isolate), and Bacillus subtilis (1 isolate). Among them, B. polymyxa exhibited the highest activity in degrading histamine than the other isolates. The ranges of temperature, pH, and salt concentration for growth and histamine degradation of B. polymyxa were 25-37°C, pH 5-9, and 0.5-5% NaCl, respectively. B. polymyxa exhibited optimal growth and histamine-degrading activity at 30°C, pH 7, and 0.5% NaCl in histamine broth for 24 hours of incubation. The histamine-degrading isolate, B. polymyxa, might be used as a starter culture in inhibiting histamine accumulation during salted fish product fermentation.