Raw Fish Meat Research Articles

MICROBIOLOGICAL QUALITY OF SOUS VIDE FISH MEAT TREATED WITH HONEY

The research was aimed at studying the influence of sous vide heat treatment on the microbiological quality of fish meat marinated in honey sauce. The samples were vacuum packed and cooked at 55°C, 60°C, 65°C and 70°C for 15 minutes. The samples were first stored for 24 hours at 4°C and then stored for 7 days at 4°C. The microbiological quality of fish meat in honey sauce were examined. Microbiological indicators such as the total viable count (TVC), the number of coliform bacteria (CB) and the lactic acid bacteria (LAB) were determined. The microbiota was identified by mass spectrometry using a MALDI-TOF MS Biotyper (Bruker Daltonics, Germany). Microbial counts varied significantly depending on temperature and storage in honey sauce. TVC in raw fish meat was 2.89 log CFU.g-1 stored at 4°C. TVC in raw fish meat was 4.56 log CFU.g-1 after 7 days of storage at 4°C. TVC in sous vide fish meat samples without honey ranged from 1.62 to 3.02 log CFU.g-1. TVC in sous vide fish meat samples with honey sauce was < 1 log CFU.g-1. The presence of coliform bacteria was not detected in the samples. LAB in raw fish meat was 2.47 log CFU.g-1 in the sample stored at 4°C. LAB in raw fish meat was 2.77 log CFU.g-1 after 7 days of storage at 4°C. LAB in sous vide fish meat samples without honey ranged from < 1 to 1.33 log CFU.g-1. LAB in sous vide fish meat samples with honey sauce ranged from < 1 to 2.66 log CFU.g-1. Our results show, that in the samples that were stored in honey sauce, the number of microorganisms decreased and even no microorganisms were detected.

Phenotypic, molecular detection and antibiogram analysis of Aeromonas Hydrophila from Oreochromis Niloticus (Nile Tilapia) and Ready-To- eat fish products in selected Rift Valley lakes of Ethiopia

BackgroundAeromonas hydrophila is a zoonotic bacterial pathogen that frequently causes disease and mass mortalities among cultured and feral fishes worldwide. In Ethiopia, A. hydrophila outbreak was reported in Sebeta fish ponds and in Lake Tana fishery. However, there is no to little information on the molecular, and phenotypical characteristics of A. hydrophila in Ethiopian fisheries. Therefore, a cross-sectional study was conducted from November 2020 to May 2021 in selected Ethiopian Rift valley lakes.ResultsA total of 140 samples were collected aseptically from fish (Muscle, Gill, Intestine, Spleen and Kidney) from fish landing sites, market and restaurants with purposive sampling methods. Aeromonas selective media (AMB), morphological and biochemical tests were used to isolate and identify A. hydrophila. Accordingly, the pathogen was isolated from 81 (60.45%) of samples. Among the isolates 92.59% expressed virulence trait through β hemolysis on blood agar media with 5% sheep blood. Moreover, 54 strains (66.67%) were further confirmed with Real-Time PCR (qPCR) using ahaI gene specific primers and optimized protocol. The highest (68.51%) were detected from live fish, (24.07%) were from market fish and the lowest (7.4%%) were from ready-to-eat products. Antibiogram analysis was conducted on ten representative isolates. Accordingly, A. hydrophila isolates were susceptible to ciprofloxacin (100%), chloramphenicol (100%) and ceftriaxone (100%). However, all ten isolates were resistant to Amoxicillin and Penicillin.ConclusionsThe study indicates A. hydrophila strains carrying virulence ahaI gene that were ß-hemolytic and resistant to antibiotics commonly used in human and veterinary medicine are circulating in the fishery. The detection of the pathogen in 140 of the sampled fish population is alarming for potential outbreaks and zoonosis. Therefore, further molecular epidemiology of the disease should be studied to establish potential inter host transmission and antibiotic resistance traits. Therefore, raising the public awareness on risk associated with consuming undercooked or raw fish meat is pertinent.

Improving the enzymatic activity of l-amino acid α-ligase for imidazole dipeptide production by site-directed mutagenesis.

Imidazole dipeptides, histidine-containing dipeptides, including carnosine (β-alanyl-l-histidine), anserine (β-alanyl-3-methyl-l-histidine), and balenine (β-alanyl-1-methyl-l-histidine) in animal muscles have physiological functions, such as significant antioxidant and antifatigue effects. They are obtained by extraction from natural raw materials, including chicken and fish meat. However, using natural raw materials entails stable supply and mass production limitations. l-amino acid α-ligase (Lal) catalyzes the formation of various dipeptides from unprotected l-amino acids by conjugating with adenosine 5'-triphosphate (ATP) hydrolysis reaction. In this study, site-directed mutagenesis of Lal was applied to establish an efficient method for producing imidazole dipeptides by the enzymatic process. We significantly improved the conversion rate from substrate amino acids compared with wild-type Lal.

Parasites with zoonotic potential found in commercially important fish in Tamaulipas, Northeastern Mexico.

Human population is exposed to numerous parasitic ichthyozoonoses. Although Tamaulipas state (northeastern Mexico) is well known for its fishing and aquaculture industry, there are few reports of this type of zoonosis. Therefore, it is imperative to investigate whether the parasites that affect these fish may represent a zoonotic risk for the inhabitants of the area. The objective of this study was to identify molecular and/or morphologically muscle parasites of fish from coastal locations in Tamaulipas, Mexico, and assess the risk of infection for humans. Between 2017 and 2018, 764 individual fish belonging to 28 species were examined for parasites. Collected worms were processed for their identification using morphological characteristics. In addition, partial sequences of the large subunit (28S) ribosomal RNA gene were obtained from some species to corroborate their identity. Prevalence and mean intensity of all registered infections were calculated. A total of seven species of parasites were found: cestodes (Poecilancistrium caryophyllum), trematodes (Clinostomum tataxumui, Clinostomum cichlidorum), nematodes (Eustrongylides sp., Contracaecum sp.) and pentastomids (Sebekia purdieae, Sebekia sp.). Parasites infected 10 species belonging to different fish families (Ariidae, Centrarchidae, Centropomidae, Cichlidae, Eleotridae, Ictaluridae, Mugilidae and Sciaenidae). Congeneric species of parasites or related to those registered in this study have been identified as zoonotic agents in other regions of the world. Despite the low levels of infection (2.6-16.6% prevalence and 1-5.5 parasites per infected host), there is a latent risk of transmission to humans, so it is recommended to avoid eating raw or undercooked fish meat.

ANALYSIS OF BACTERIAL DIVERSITY IN RAW FISH CEVICHE

Ceviche is a traditional dish made from raw fish meat marinated in lime juice without any heat cooking step throughout its preparation process. Although the use of organic acids as antibacterial agents is well known; recent research indicates that lime juice actually can reduce the risk of V. parahemolyticus infections but it is ineffective against other potential pathogens. Despite the fact that fresh fish meat is safe; exposed organs including skin, gills and guts represent a potential source of bacterial contamination. In Mexico, diarrheal diseases are caused mainly by contaminated food; it is estimated that almost 67% of infections are due the presence of bacterial agents mainly in frozen and fresh fish. The main objective of this study was to estimate the taxonomic diversity of microbial species present in ready-to-eat ceviche using a metagenomic approach. Six samples of commercially available ceviche were subjected to DNA high throughput sequencing and bioinformatics analyses, we identified between 65,000 and 131,000 reads per sample. The predominant phyla identified through the samples were Proteobacteria, Bacteroidetes and Firmicutes. We discuss the factors involved in the microbiological quality of this kind of raw foods and how they influence the bacterial diversity within the analyzed samples.

Detection of Klebsiella pneumoniae antibiotic-resistant genes: An impending source of multidrug resistance dissemination through raw food

This study aimed to find out the prevalence and antimicrobial resistance profile of Klebsiella pneumoniae in raw food items. A total of 261 raw food items, including vegetables, fruits, meat, and milk samples, were collected and processed for isolation of K.pneumoniae. Further antimicrobial susceptibility testing and molecular analysis was done to analyze the drug resistance encoding genes. The prevalence rate of K.pneumoniae was found to be high (38%), and the raw milk samples were predominantly contaminated (19/51), followed by fruits (12/51), meat (11/51), and vegetables (9/51). However, no significant association was observed for the isolation of K.pneumoniae and any particular specimen. Among the isolates, 43% were extended-spectrum β-lactamase producers, 24% were AmpC, and 20% were carbapenemase producers. The highest rates of ESBLs and AmpC were observed in vegetables (cabbage, bell pepper, and spinach) and carbapenemases in raw chicken, fish, and raw meat samples. Notably, blaCTX-M was the most prevalent, followed by blaSHV and blaTEM. Six K.pneumoniae possessed blaMOX, and five possessed blaFOX genes. Numerous carbapenemases were identified with a higher proportion of blaNDM. This study indicates that raw vegetables, fruits, meat, and milk are exposed to contaminants. These findings imply a potential threat that drug-resistant K.pneumoniae pathogens could transmit to humans through raw vegetables, fruits, and meat.

Disorders caused by contaminated fish meat consumption: Literature review / Doenças causadas por consume de carne de peixe contaminada: Revisão de literatura

Between 2007 and 2017, Brazil registered 99,826 outbreaks of foodborne diseases and 0.84% of those were associated with fish meat intake. It is estimated that approximately 56 million infection cases occur worldwide due to raw or undercooked fish meat containing several disease-causing parasites. Hence, this study aimed to review the literature concerning diseases caused by ingestion of contaminated fish meat. Reviews, case reports and epidemiologic studies were searched in Portuguese, Spanish and English in the databases LILACS, Pubmed, Science Direct, SciElo and Scholar Google using as keywords: transmissive diseases, contaminated fish and human infections were used to retrieve papers from 2014 to 2020. Nine papers, including seven reviews, one case report and one case-control study fulfilled inclusion criteria and presented several consequences of contaminated raw or undercooked fish meat ingestion, which ranged from nemathode, bacterial and toxin diseases that may cause gastrointestinal problems to allergic reactions, lung infection, endemic acute myalgia, bacteremia, meningitis and death. Growing fish meat intake in several dishes presents significant health risk due to the pathogenic potential of toxins and parasites that remain when food is consumed raw or undercooked. Tighter sanitary surveillance, population health education, training and sensitization of health professionals in recognizing and notifying cases might contribute to minimize risk.

ANALYSIS OF BACTERIAL DIVERSITY IN RAW FISH CEVICHE

Ceviche is a traditional dish made from raw fish meat marinated in lime juice without any heat cooking step throughout its preparation process. Although the use of organic acids as antibacterial agents is well known; recent research indicates that lime juice actually can reduce the risk of V. parahemolyticus infections but it is ineffective against other potential pathogens. Despite the fact that fresh fish meat is safe; exposed organs including skin, gills and guts represent a potential source of bacterial contamination. In Mexico, diarrheal diseases are caused mainly by contaminated food; it is estimated that almost 67% of infections are due the presence of bacterial agents mainly in frozen and fresh fish. The main objective of this study was to estimate the taxonomic diversity of microbial species present in ready-to-eat ceviche using a metagenomic approach. Six samples of commercially available ceviche were subjected to DNA high throughput sequencing and bioinformatics analyses, we identified between 65,000 and 131,000 reads per sample. The predominant phyla identified through the samples were Proteobacteria, Bacteroidetes and Firmicutes. We discuss the factors involved in the microbiological quality of this kind of raw foods and how they influence the bacterial diversity within the analyzed samples.

Influence of the interposition of pink muscle fibers in the dorsal ordinary muscle on the postmortem hardness of meat in various fishes.

We previously showed that the tenderization of ordinary muscle during ice storage is affected by the interposition of pink muscle fibers in the ordinary muscle. However, little is known about whether or not the interposition of pink muscle fibers affects the hardness of raw fish meat. To clarify the influence of the interposition of pink muscle fibers in the dorsal ordinary muscle on hardness of meat, the breaking strengths and the fiber types of the dorsal ordinary muscle of eight fish species (a total of 37 specimens) were discriminated. The breaking strengths among fish species were within a range of 6.5-19.1 N/cm2 . Pink muscle fibers were found in the dorsal ordinary muscle of six out of the eight fish species ranging from 0.0 to 56.0% in quantity ratio, and 0.0 to 19.3% in area ratio, respectively. The quantity ratio and area ratio of pink muscle fibers in the dorsal ordinary muscles of all eight fish species samples positively correlated with the breaking strength. Relative to the quantity ratio (p < .05), the area ratio (p < .02) of pink muscle fibers was more representative of postmortem texture hardness. In conclusion, the high interposition ratio of pink muscle fibers in ordinary muscle could potentially improve the postmortem hardness, the texture, and even the flesh quality of raw fish meat.

Description of myxosporeans (Cnidaria: Myxozoa) infecting the popular food fish Notopterus notopterus (Pisces: Notopteridae) in Malaysia and India

This study was a co-operative investigation of myxosporean infections of Notopterus notopterus, the bronze featherback, which is a popular food fish in the South Asian region. We examined fish from Lake Kenyir, Malaysia and the River Ganga, Hastinapur, Uttar Pradesh, India, and observed infections with two myxosporeans: Myxidium cf. notopterum (Myxidiidae) and Henneguya ganapatiae (Myxobolidae), respectively. These species were identified by myxospore morphology, morphometry and host tissue affinity, and the original descriptions supplemented with small-subunit ribosomal DNA sequences and phylogenetic analysis. Free myxospores of M. cf. notopterum were found in the gallbladder, and measured 14.7 ± 0.6 μm long and 6.3 ± 0.6 μm wide; host, tissue and myxospore dimensions overlapped with the type, but differed in morphological details (spore shape, valve cell ridges) and locality (Malaysia versus India). Plasmodia and spores of H. ganapatiae were observed in gills, and myxospores had a spore body 9.7 ± 0.4 μm long, 4.5 ± 0.5 μm wide; sample locality, host, tissue, spore morphology and morphometry matched the original description. Small-subunit ribosomal DNA sequences were deposited in GenBank (M. cf. notopterum MT365527, H. ganapatiae MT365528) and both differed by >7% from congeneric species. Although the pathogenicity and clinical manifestation of myxozoan in humans are poorly understood, consumption of raw fish meat with myxozoan infection was reported to be associated with diarrhea. Identification of current parasite fauna from N. notopterus is an essential first step in assessing pathogen risks to stocks of this important food fish.

Investigation of Anisakis larvae in different products of ready-to-eat fish meat and imported frozen fish in Turkey

Globalization opens new market areas and affects food consumption habits, resulting in rapid and remarkable cultural change. Food habits such as consumption of raw fish meat have become popular, resulting in increased risk of emerging infectious diseases. Anisakis simplex sensu stricto (s.s) and A. pegreffii are the most common and important fish-borne zoonotic nematodes responsible for human anisakiasis, which occurs through the consumption of raw or undercooked fish as well as cooked fish due to their heat-stable allergens. Here, we investigated the prevalence, intensity, and abundance of Anisakis larvae in imported fish and ready-to-eat local fish products in Turkey. A total of 205 ready-to-eat fish products, 100 imported frozen Atlantic salmon (Salmo salar) fillets, and 100 imported frozen whole Atlantic mackerel (Scomber scombrus) were sampled from supermarkets, sushi restaurants, and fish markets. All samples were individually examined using a pepsin digestion technique. In total, 602 Anisakis type I larvae were recovered from 98/100 mackerel. No larvae were found in ready-to-eat products or frozen Atlantic salmon fillets. Overall, 8.8% of the larvae were found in the muscle tissue. The overall mean intensity and abundance of infection in mackerel were 6.14 and 6.02, respectively. The larvae were molecularly identified and their phylogenetic relationships with the relevant Anisakis sequences in GenBank were investigated. For this purpose, a subsample of randomly selected 100 Anisakis larvae were analyzed with PCR-RFLP of the ITS region. The larvae were identified as A. simplex (s.s.) (n = 87) and hybrids (n = 13). ITS and cox2 gene regions of all hybrids and randomly selected 50 A. simplex (s.s.) larvae were sequenced for species confirmation and phylogenetic analyses. No intraspecific nucleotide variation was found among the ITS sequences of either species. Seven and three haplotypes, respectively, were identified for A. simplex (s.s.) and hybrid species according to DNA polymorphism of the cox2 gene. Hybrids in our study clustered within the common A. simplex (s.s.) clade in the cox2 phylogenetic tree indicating the dominance of A. simplex (s.s) in the catching area of Atlantic mackerel. Consequently, our study indicates high occurrence of A. simplex (s.s.) larvae with an overall 98.0% prevalence in imported Atlantic mackerel, and highlights the importance of these fish as potential reservoirs for human allergic anisakiasis in Turkey and possibly in other countries.

Contracaecum multipapillatum (Nematoda: Anisakidae) en peces de aguas continentales de Guanacaste, Costa Rica e Izabal, Guatemala

Contracaecum multipapillatum infecta peces como hospedadores intermediarios y al ser humano como hospedador accidental por consumo de carne de pescado cruda o semi cocinada. Este riesgo para la salud humana hace importante determinar su prevalencia, intensidad de infección y ubicación anatómica en peces destinados al consumo mediante pesca artesanal; y la influencia de parámetros físicoquímicos del agua sobre la infección en peces. Se recolectaron 214 peces en 6 ríos de Cañas, Guanacaste, Costa Rica y 203 peces en el Lago de Izabal y Río Dulce, Izabal, Guatemala. En los sitios de pesca se tomaron parámetros físicoquímicos del agua (temperatura, pH y oxígeno disuelto). La prevalencia de infección fue 16.8% y 25.1% en Guanacaste e Izabal, respectivamente, encontrándose 105 larvas de tercer estadio (L3) en 36 peces de Guanacaste y 135 L3 en 51 peces de Izabal. Se observó afinidad de L3 por órganos viscerales (22.4% en Guanacaste – 25.1% en Izabal) y menor por tejido muscular (2.0% en Guanacaste – 1.0% en Izabal). La intensidad de infección directamente proporcional con la talla y peso de los peces (una larva en 13 peces con peso y talla media de 66.7 g y 17.5 cm en Guanacaste, y siete peces de 214.9 g y 28.4 cm en Izabal; y 14 larvas en un pez de 148.8 g y 24 cm en Guanacaste y 12 larvas en un pez de 260 g y 40 cm en Izabal). No se observó asociación entre parámetros fisicoquímicos del agua y susceptibilidad de peces a infección.

Physicochemical characterization and microbiological analysis of Oligosarcus robustus raw fish meat and development a fish hamburger

Physicochemical characterization and microbiological analysis of Oligosarcus robustus raw fish meat and development a fish hamburger

Effect of steaming and pressurized boiling process to the nutrient profile of Papuan cork fish Channastriata as potential protein-rich food to prevent stunting

ObjectiveThis study was to analyze the chemical composition of cork fish (Channa striata) of Papua Indonesia. MethodCork fish meat was steamed and pressure boiled to get filtrate and oil. Raw fish meat, steaming process, and pressurized boiling sample were analyzed for proximate, amino acid, and fatty acid. ResultProximate analysis revealed that protein content and fat content of dry raw fish meat were 58.68% and 0.65%, respectively. The total amino acid of raw fish meat, steaming process filtrate, and pressure boiled filtrate were 67.49%, 3.38%, and 1.54%, respectively. The total fatty acid of raw fish meat, steaming process oil, and pressure boiled oil were 67.28%, 72.75%, and 85.14%, successively. ConclusionCork fish (Channa striata) from Merauke Region of Papua, Indonesia shows the high protein content and interesting profile of amino acid and fatty acid that makes it potential to prevent stunting. C. striata fish is a good source of amino acid, and fatty acid can be served by steaming or pressurized boiling process.

Current status of Opisthorchis viverrini, minute intestinal fluke and Taenia spp. infections among inhabitants in the Kenethao district of northern Lao PDR

This study reports the prevalence of Ov/minute intestinal fluke (MIF) and Taenia infections among inhabitants of the Kenethao district, northern Lao PDR. Fecal samples from 580 inhabitants were examined using the formalin-ethyl acetate concentration technique. The prevalence of Ov/MIF, Taenia spp. and coinfection was 45.3, 11.9 and 6.1%, respectively. There was no significant difference between males and females for Ov/MIF (p=0.813) and Taenia infection (p=0.759). The prevalence of Ov/MIF was significantly associated with age (p=0.005), but not for Taenia infection (p=0.836). Consumption of raw fish (p=0.001) and raw meat (p=0.046) was significantly associated with parasitic infections. The results suggest that Ov/MIF and Taenia spp. are highly endemic in this area and there is a need for projects to eliminate these parasites.

&lt;i&gt;Contracaecum&lt;i&gt; spp. (NEMATODA: ANISAKIDAE) AND &lt;i&gt;Eustrongylides&lt;i&gt; spp. (NEMATODA: DIOCTOPHYMATIDAE) NEMATODE LARVAE WITH ZOONOTIC POTENCIAL FOUND IN TWO FISH SPECIES FROM TRAMANDAÍ RIVER BASIN, SOUTHERN BRAZIL

Parasitic nematodes can infect both wild and cultivated fish species and may be the source of many diseases. The consumption of raw fish meat in many countries has been the responsible of nematode related zoonosis. Knowing the risk of consumption of contaminated fish by the local communities, the main goal of this paper is to quantify and report the presence of larvae with zoonotic potential of Contracaecum spp. and Eustrongylides spp. found in two exotic fish species from the Tramandaí­­ River Basin in southern Brazil. The sample sites were two lagoons of the basin, the Itapeva lagoon and Palmital lagoon, sampled in the period of April 2018. Forty specimens of Acestrorhynchus pantaneiro and twenty specimens of Trachelyopterus lucenai were examined. A. pantaneiro presented a 58% and 4% prevalence and a mean intensity of 3.17 and 1 for Contracaecum spp. and Eustrongylides spp., respectively. Meanwhile T. lucenai presented a prevalence of 70% and 5% and a mean intensity of 1.92 and 1 of Contracaecum spp. larvae and Eustrongylides spp. larvae, respectively. Although larvae of Contracaeucum spp. are reported only in the literature in experimental infections, they were able to complete their biological cycle in some mammals with certain pathogeneses. However, larvae of Eustrongylides spp. infect humans, as reported in the literature, causing severe damage to the intestinal tract. Knowing that local populations may be at risk, we recommend that all prophylactic measures be taken in relation to fish consumption. This study also contributes to the knowledge concerning the parasitic fauna of the host species studied.

Predictive risk factors towards liver fluke infection among the people in Kamalasai District, Kalasin Province, Thailand.

Background:Liver fluke disease caused by Opisthorchis viverrini remains a major public health problem with its crucial risk factors caused by some individual habits or false beliefs among the people in northeastern Thailand concerning the consumption of raw fish meat dishes.Objectives:This study explores the predictive risk factors for the infection of liver fluke disease.Methods:The sample consisted of 400 people aged 30 years and above in Thanya sub-district, Kamalasai district, Kalasin province. A cross-sectional analytic study, using the χ2 test, odds ratio and 95% confidence interval, was used to find the influence of each variable, along with the use of multiple logistic regression (p = 0.05). A questionnaire form was used as the research instrument.Results:Factors found in the results are as follows: households with a cat were 7.00 times more at risk than households without a cat; eating raw fish dishes prepared by themselves increases the risk of infection by 2.58 times; eating raw fish dishes prepared by family members increases the risk by 4.74 times; and raw fish dishes bought from a community market increases the risk by 2.33 times.Conclusion:A campaign should be launched to educate people not to eat raw or undercooked fish dishes, but to fully cook fish dishes before eating, as the food is still delicious, but also safe, healthy, and free from liver fluke infection.

Determination of Volatile Amines Using Needle-Type Extraction Coupled with Gas Chromatography–Barrier Discharge Ionization Detection

Volatile amines including ammonia, methylamine, dimethylamine, ethylamine, and trimethylamine were extracted using a needle-type extraction device followed by determination using a gas chromatography–barrier discharge ionization detector. The analyte amines were extracted based on their reaction with an organic acid in the needle packed by the adsorbent. The extracted compounds were desorbed by heating the extraction needle in the GC injection port and introduced into a GC column. After optimization of the desorption process, the proposed method was quantitatively evaluated for linearity, repeatability, and sensitivity. The limits of detection for ammonia, methylamine, dimethylamine, ethylamine, and trimethylamine with an air sampling volume of 100 mL were 0.03, 0.1, 1, 0.06 and 0.05 µg L−1, respectively. The method was applied to the determination of amines from raw fish and raw meat samples.

The occurrence of Contracaecum sp. larvae (Nematoda: Anisakidae) in four teleostean species from Lake Nasser, Egypt: morphological and molecular studies

BackgroundNematodes of the family Anisakidae are parasites of many fishes and aquatic invertebrates which act as intermediate or paratenic hosts, while mammals and fish-eating birds are definitive hosts. Infective L3 larvae may be incidentally taken by human through eating raw or undercooked fish meat, causing anisakidosis. The main purpose of this study is to provide a basis for the future investigations to discover the genetic diversity of this widely distributed parasite nematodes of fishes and fish eating animals and their effect on fisheries and public health in Egypt and worldwide.ResultsOne thousand, one hundred and fifteen specimens belong to nine fish species were collected from Lake Nasser, Egypt, and examined for infection with Anisakid larvae. Four fish species (Oreochromis niloticus, Tilapia galilaea, Lates niloticus, and Hydrocynus forskahlii) were found infected with third stage larvae of Contracaecum spp. No other Anisakid nematodes were detected. Larvae were found in the body cavity adhering to mesenteries by a thin membrane, except in Oreochromis niloticus and Tilapia galilaea were found free in branchial chambers. The highest prevalence was recorded in L. niloticus (100%) and H. forskahlii (82%). The mean intensity of infections were 0.17–4.12 and 5.1–10.3 in L. niloticus and H. forskahlii respectively. For further identification, the internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA from isolated larvae (n = 54) were amplified by PCR, followed by single-strand conformation polymorphism (SSCP) analysis which revealed five possible profiles.ConclusionLight and scanning electron microscope studies revealed that all anisakid larvae in the present study showed the most typical features of the genus Contracaecum. The sequencing (n = 28) and sequence and phylogenetic analyses showed that the present nematode larvae are likely belonging to C. multipapillatum.

One-Minute Fish Freshness Evaluation by Testing the Volatile Amine Gas with an Ultrasensitive Porous-Electrode-Capped Organic Gas Sensor System.

In this work, we successfully demonstrate a fast method to determine the fish freshness by using a sensing system containing an ultrasensitive amine gas sensor to detect the volatile amine gas from the raw fish meat. When traditional titration method takes 4 h and complicated steps to test the total volatile basic nitrogen (TVB-N) as a worldwide standard for fish freshness, our sensor takes 1 min to deliver an electrical sensing response that is highly correlated with the TVB-N value. When detecting a fresh fish with a TVB-N as 18 mg/100 g, the sensor delivers an effective ammonia concentration as 100 ppb. For TVB-N as 28-35 mg/100 g, a well-accepted freshness limit, the effective ammonia concentration is as 200-300 ppb. The ppb-regime sensitivity of the sensor and the humidity control in the sensing system are the keys to realizing fast and accurate detection. It is expected that the results in this report enable the development of on-site freshness detection and real-time monitoring in a fish factory.