Multisyringe Flow Injection Analysis of Tropomyosin Allergens in Shellfish Samples

This paper presents the development and the application of a multisyringe flow injection analysis system for the fluorimetric determination of the major heat-stable known allergen in shrimp, rPen a 1 (tropomyosin). This muscle protein, made up of 284 amino acids, is the main allergen in crustaceans and can be hydrolyzed by microwave in hydrochloric acid medium to produce glutamic acid, the major amino acid in the protein. Glutamic acid can then be quantified specifically by thermal conversion into pyroglutamic acid followed by chemical derivatization of the pyroglutamic acid formed by an analytical protocol based on an OPA-NAC reagent. Pyroglutamic acid can thus be quantified between 1 and 100 µM in less than 15 min with a detection limit of 1.3 µM. The method has been validated by measurements on real samples demonstrating that the response increases with the increase in the tropomyosin content or with the increase in the mass of the shrimp sample.

Identification of a novel metallo-β-lactamase, VAM-1, in a foodborne Vibrio alginolyticus isolate from China

A multidrug-resistant Vibrio alginolyticus isolate recovered from a shrimp sample with reduced carbapenem susceptibility produced a novel metallo-β-lactamase, VAM-1. That carbapenemase shared 67% to 70% amino acid identity with several VMB family subclass B1 MBLs which were recently reported among some marine bacteria including Vibrio , Glaciecola and Thalassomonas . The bla VAM-1 gene was located in a novel conjugative plasmid, namely pC1579 and multiple copies of bla VAM-1 via an unusual mechanism of gene amplification were detected in pC1579. These findings underline the emergence of marine organisms acting as natural reservoirs for MBL genes and the importance of continuous bacterial antibiotic resistance surveillance.

Evaluation of Microwave Applicator Design on Electromagnetic Field Distribution and Heating Pattern of Cooked Peeled Shrimp

Non-uniform temperature distribution within solid food is a major problem associated with microwave heating, which limits industrial applications. Therefore, an experimentally validated 3D model was proposed to study the effect of microwave applicator geometry on the electromagnetic field distribution and heating pattern of shrimp under different processing conditions. Simulation results were compared with physical experiments, in which a cooked peeled shrimp sample was heated using two different laboratory-scale microwave applicators (rectangular and cylindrical cavities). For the rectangular applicator, the temperature distribution within the shrimp, when examined in cross-section, was more homogeneous compared to that of the cylindrical applicator. The results showed the influence of the complex shape of the food on the temperature distribution during microwave heating, as well as of process parameters (input power and geometry cavity). Moreover, this modelling method could provide a better understanding of the microwave heating process and assist manufacturing companies to evaluate a suitable microwave applicator according to their specific purpose.

Whole-Genome Sequence Analysis of Multidrug-Resistant Enterobacter hormaechei Isolated from Imported Retail Shrimp

ABSTRACT Here, we announce the draft genome sequence of Enterobacter hormaechei 2B-MC1, isolated from a shrimp sample collected from a farmer’s market in Atlanta, Georgia. The assembled genome sequence observed was 4,661,561 bp long with a G+C content of 55.3%. The isolate harbored sul1, sul2, qnrA1, oqxB, dfrA23, blaACT, floR, fosA, tet(A), aph(6)-Id, and aph(3″)-Ib antibiotic resistance genes.

HEAVY METAL CADMIUM (Cd) AND LEAD (Pb) IN VANAME SHRIMP (Litopenaeus vannamei) COLLECTED FROM TRADITIONAL MARKETS IN MEDAN CITY, INDONESIA

The presence of heavy metals in the aquatic environment must be monitored continuously. This study aims to determine the amount of heavy metal content of Cadmium (Cd) and Lead (Pb) on Vaname Shrimp (Litopenaeus vannamei). Determining the value of Cadmium (Cd) and Lead (Pb) using an AAS (Atomic Absorption Spectrophotometer) device. It is known that the highest Cd content in the sample 4 (market pancing) which is worth 0.011 mg/kg, and the lowest is in the sample 6 (market sei kambing) which is worth 0.004 mg/kg. The value of the highest Pb value is found in the sample 3 (market merah) worth 0.019 and the lowest value is the sample 5 (market petisah) worth 0.008. So that the results of these tests can be concluded, that the content of heavy metals Cd and Pb in each sample of vaname shrimp is classified as low according to the World Health Organization (WHO), namely the maximum limit of Cd is 5.0 and the maximum limit of Pb is 2.0 while according to EUROPEAN UNION the limit of calcium Cd is 0.2 and the maximum limit of Pb is 0.5 because the vaname shrimp sample is still safe for consumption and can be an export commodity.

ISOLASI DAN KARAKTERISASI KITIN DARI LIMBAH UDANG

Isolation and Characterization of Chitin From Shrimp Waste Chitin is a natural biopolymer that is widespread in nature and the second abundance only to cellulose organic compounds are available in the earth. In general, in nature chitin are not included in the free state, but binds to the protein, mineral and pigment in various animal skeletons group of arthropoda, annelida, mollusk, coelenterata, nematodes, insects, and some classes of fungi and the organic constituent part is very important. Average shrimp shell contains 25-40% protein, 40-50% CaCO3 and 15-20% chitin, but the magnitude of the component content is still dependent on species and habitats. Although chitin is widespread in nature, but the main source that can be utilized as a source of chitin is the use of shrimp waste. This is because the shrimp waste easily obtained in large quantities that can be produced commercially. The purpose of this study was to determine how the isolation of chitin from shrimp waste by chemical processes and their characterization and compare in detail the content of chitin found in the head, body and tail skin of the shrimp. In addition, to determine the effect of insulating phases of chitin to chitin produced. This study is an experimental research by isolation of chitin in the head, body and tail skin of the shrimp. In the early stages of shrimp waste preparation where the head and skin of the body and tail of each shrimp was separated, cleaned, dried, and milled. Chitin isolation process is done by two ways in which the first stage on the way deproteination done first and subsequent demineralization stages. While in the second stage of demineralization way done first, followed deproteination stage. In phase deproteinasi NaOH 1N solution with a ratio of 1: 10 (by weight of shrimp sample: NaOH 1N). This process was carried out at a temperature of 65oC for three hours. While in the process of demineralization using HCl 2N solution and soaked for 2 hours with a comparison between the shells samples with HCl used are 1: 15. After that just do the bleaching process. Each repetition of the way done twice. Research results show that the insulating phase difference of chitin used apparently affect the yield and ash content obtained, where the first way yield of chitin and ash content obtained was higher yield compared to the results obtained of the latter, while the drying process was done would affect water levels obtained. In the solubility test, partially chitin produced solved in LiCl or dimethylacetamide. Overall chitin obtained meet the requirements of the specification of commercial chitin. In addition, from the head, the skin of the body and the tail of shrimp the higest chitin content ever found was on the skin of the bodyKey words : Isolation, Characterization, Chitin, and Shrimp Waste ABSTRAK Kitin adalah biopolimer alami yang tersebar luas di alam dan merupakan senyawa organik kedua setelah selulosa yang sangat melimpah di bumi. Pada umumnya kitin di alam tidak terdapat dalam keadaan bebas, akan tetapi berikatan dengan protein, mineral dan berbagai macam pigmen pada kerangka hewan golongan Arthropoda, Annelida, Molusca, Coelenterata, Nematoda, beberapa kelas serangga serta jamur dan merupakan bagian konstituen organik yang sangat penting. Rata-rata kulit udang mengandung 25-40% protein, 40-50% CaCO3 dan 15-20% kitin, tetapi besarnya kandungan komponen tersebut juga masih tergantung kepada spesies dan habitat. Walaupun kitin tersebar luas di alam, akan tetapi sumber utama yang dapat dimanfaatkan sebagai sumber kitin adalah penggunaan limbah udang. Hal ini dikarenakan limbah udang mudah diperoleh dalam jumlah banyak sehingga dapat diproduksi secara komersial.Tujuan dari penelitian ini adalah untuk mengetahui cara isolasi kitin dari limbah udang dengan proses kimia beserta karakterisasinya dan membandingkan secara terperinci kandungan kitin yang terdapat pada bagian kepala, kulit bagian badan dan ekor udang. Selain itu juga untuk mengetahui pengaruh dari tahapan isolasi kitin terhadap kitin yang dihasilkan. Penelitian ini merupakan penelitian eksperimental dengan melakukan isolasi kitin pada bagian kepala, kulit bagian badan dan ekor udang. Pada tahap awal dilakukan preparasi limbah udang dimana bagian kepala, kulit bagian badan dan ekor udang masing-masing dipisahkan dan dibersihkan, lalu dikeringkan dan digiling. Proses isolasi kitin dilakukan dengan dengan dua cara dimana pada cara pertama tahap deproteinasi dilakukan terlebih dahulu dan berikutnya tahap demineralisasi. Sementara pada cara kedua tahap demineralisasi dilakukan terlebih dahulu, lalu diikuti tahap deproteinasi. Pada tahap deproteinasi menggunakan larutan NaOH 1N dengan perbandingan 1 : 10 (berat sampel kulit udang : NaOH 1N). Proses ini dilakukan pada suhu 65oC selama tiga jam. Sementara pada proses demineralisasi menggunakan larutan HCl 2N dan direndam selama 2 jam dengan perbandingan antara sampel kulit udang dengan HCl yang digunakan adalah 1 : 15. Setelah itu baru dilakukan proses pemutihan. Masing-masing cara dilakukan pengulangan sebanyak dua kali. Hasil Penelitian menunjukkan bahwa perbedaan tahap isolasi kitin yang digunakan ternyata berpengaruh terhadap rendemen hasil dan kadar abu yang didapatkan, dimana pada cara pertama rendemen hasil kitin dan kadar abu yang didapatkan lebih tinggi dibandingkan dengan rendemen hasil yang didapatkan pada cara kedua, sedangkan proses pengeringan yang dilakukan akan berpengaruh terhadap kadar air yang didapatkan. Pada uji kelarutan, kitin yang dihasilkan larut sebagian dengan LiCl atau dimetilasetamida. Secara keseluruhan kitin yang diperoleh memenuhi persyaratan dari spesifikasi kitin niaga. Selain itu dari bagian kepala, kulit bagian badan dan ekor udang kandungan kitin terbanyak terdapat pada kulit bagian badanKata kunci : Isolasi, karakterisasi, kitin, dan limbah udang

Genetic Characterization of ablaVEB-2-Carrying Plasmid in Vibrio parahaemolyticus

ABSTRACTThis report describes the first detection of ablaVEB-2gene in aVibrio parahaemolyticusstrain isolated from a shrimp sample. TheblaVEB-2gene was carried on a novel Inc-type plasmid that was likely to have originated from aquatic organisms, as indicated by a comparison with other known genetic elements in the GenBank database. However, the plasmid contains resistance elements usually harbored by members of the familyEnterobacteriaceae, suggesting that gene transfer events occurred and contributed to the formation of this multidrug resistance-encoding plasmid.

Development of a Quantitative Multiclass/Multiresidue Method for 21 Veterinary Drugs in Shrimp

A multiclass/multiresidue method has been developed and validated for the determination of 21 veterinary drug residues in shrimp, including sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfachloropyridazine, sulfadimethoxine, and sulfaquinoxaline); tetracyclines (oxytetracycline, tetracycline, and chlortetracycline); (fluoro)quinolones (norfloxacin, ciprofloxacin, enrofloxacin, sarafloxacin, difloxacin, flumequine, oxolinic acid, and nalidixic acid); and cationic dyes (malachite green, gentian violet, leucomalachite green, and leucogentian violet), using HPLC/MS/MS. All drugs were quantifiable over a no less than 10-fold range with matrix-matched standards for linear external calibration, except for oxytetracycline, tetracycline, norfloxacin, and ciprofloxacin, for which norfloxacin-d5 was used as an internal standard. Two grams of preground shrimp sample was extracted twice with extractant at two different pH values. The combined supernatant was further diluted with an aqueous internal standard solution, and 50 L extract was injected into the HPLC instrument. An online SPE system was set up for automated sample cleanup. A triple quadrupole mass spectrometer equipped with an electrospray ionization source was operated in the multiple-reaction-monitoring mode to acquire data. The method has been validated at three levels within the designated linear ranges for each drug, with accuracies between 77 and 115, and most CV values below 15.

Molecular Screening, Isolation, and Characterization of Enterohemorrhagic Escherichia coli O157:H7 from Retail Shrimp

Foodborne outbreaks attributed to the contamination of foods with enterohemorrhagic Escherichia coli (EHEC) O157:H7 are a growing global concern. Fish and shrimp samples obtained from different retail fish markets in Cochin, India, were screened by direct PCR assays targeting three important virulence markers of EHEC, the intimin protein (eaeA gene), enterohemolysin (hlyA gene), and Shiga toxin (stx gene). One shrimp (Fenneropenaeus indicus) sample was positive for all these virulence markers, and seven typical E. coli O157:H7 isolates were recovered from the marker-positive shrimp sample. This is the first report of recovery of typical E. coli O157:H7 from fish or shellfish in India. All the typical EHEC isolates had a characteristic reaction in eosin methylene blue agar and belonged to IMViC (indole, methyl red, Voges Proskauer, Simmons citrate reactions) biotype I. These isolates also were negative for sorbitol and methylumbelliferyl-β -glucuronide and exhibited β-hemolytic activity. One isolate showed self-agglutination for E. coli O157 antisera and produced a false-positive reaction with CHROMagar O157. These typical EHEC isolates belonged to a restricted biotype group and had a very low multiple antibiotic resistance index. Isolation of E. coli O157:H7 in fish and shellfish indicates that strict adherence to hygienic handling methods and proper cooking or processing is needed before consumption of these products.