A rapid and simple method for the determination of Formaldehyde in Fishery Products

The content of free formaldehyde (FA) in minced fish muscle was measured by the following procedure: A mixture of minced fish muscle and water was deproteinized by means of the Carrez reagent. The FA content of the filtrate was determined reflectometrically using the Reflectoquant test strips and the RQflex. The results agreed well with the colorimetrically (Nash test) measured FA content. Der Gehalt an freiem Formaldehyd (FA)in Fischerzeugnissen wurde mit folgender Methode bestimmt: Zerkleinertes Fischfleisch wurde mit Wasser homogenisiert und mit Carrez-Reagenz enteiweißt. Der Formaldehydgehalt des Filtrates wurde reflektometrisch unter Verwendung von Reflectoquant-Teststätbchen und des RQflex ermittelt. Die Ergebnisse stimmten gut mit kolorimetrisch (Nash Test) gemessenen FA-Gehalten überein.

Fish species identification in Canned Tuna by DNA Analysis (PCR-SSCP)

DNA in canned tuna is degraded into short fragments of a rew hundred base pairs. The polymerase chain reaction (PCR) was used to amplify short sequences of mitochondrial DNA, which were denatured and analysed by polyacrylamide gel electrophoresis (native PAGE) for detection of single strand conformation polymorphisms. Species specific patterns of DNA bands were obtained for a number of tuna and bonito species. DE: In Thunfischkonserven liegt die DNA in Form kurzkettiger Fragmente von wenigen Hundert Basenpaaren Länge vor. Mit Hilfe der Polymerase-Kettenreaktion (PCR) wurden kurze Sequenzen der mitochondrialen DNA vervielfältigt. Anschließend wurde die gebildete DNA in Einzelsträngen überführt, die durch eine native Polyacrylamidgel-Elektrophorese (PAGE) aufgetrennt wurde. Für eine Reihe von Thunfischen und Boniten ergaben die Einzelstränge artspezifische Bandenmuster, die auf unterschiedliche Konformationen der DNA-Stränge der einzelnen Fischarten zurückzuführen sind.

White spot syndrome virus (WSSV) transmission risk through infected cooked shrimp products assessed by polymerase chain reaction (PCR) and bio-inoculation studies

The aim of the study was to evaluate the resistance of white spot syndrome virus (WSSV) in shrimps (Penaeus monodon) to the process of cooking. The cooking was carried out at 1000C six different durations 5, 10, 15, 20, 25 and 30 min. The presence of WSSV was tested by single step and nested polymerase chain reaction (PCR). In the single step PCR, the primers 1s5 & 1a16 and IK1 & IK2 were used. While in the nested PCR, primers IK1 &IK2 – IK3 & IK4 were used for the detection of WSSV. WSSV was detected in the single step PCR with the primers 1s5 and 1a16 and the nested PCR with the primers IK1 and IK2 – IK3 & IK4 from the cooked shrimp samples. The cooked shrimps, which gave positive results for WSSV by PCR, were further confirmed for the viability of WSSV by conducting the bio-inoculation studies. Mortality (100%) was observed within 123 h of intra-muscular post injection (P.I) into the live healthy WSSV-free shrimps (P. monodon). These results show that the WSSV survive the cooking process and even infected cooked shrimp products may pose a transmission risk for WSSV to the native shrimp farming systems.

Effect of crude oil and some petroleum products on Clarias Gariepinus fingerlings (Catfish: Claridae)

Ninety (90) hatchery bred fingerlings of Clarias gariepinus (mean weight: 0.96 ± 0.1g) were randomly placed in 15 plastic baths (25 litres each) at the Research laboratory and were exposed to different concentrations of oil products to determine their effects on the fish, to facilitate inferential deductions that will enhance effective aquatic environmental management. Three (3) replicate basins of 5 experimental treatments (crude oil, petrol oil, kerosene oil, engine oil and control) were used at a concentration of 1.25ml. L-1. The control experiment was devoid of oil treatment. Six (6) fingerlings were placed in each replicate basin, flooded with 20 litres of clean tap water and fed with nutrafin cichilid food, 2 times daily at 3% body weight. The results showed that the feeding behaviour and swimming performances of fish were reduced after 24 hours of the addition of the various oil pollutants. Mortality of fingerlings in the oiled basins increased as the hours of exposure increased (i.e. 24, 48, 72 and 96 hours). Recovery was not immediate in the treated basin while surviving fingerlings in the control basins grew up to post-fingerlings after 90 days (3 months). There were significant differences (P<0.01 and P<0.05) in the effect of crude oil and the petroleum products on the mortality rate of C. gariepinus when exposed to oil pollutants at 1.25ml. L-1 concentration

Viability of seeds in food products proposed for field trips in Galapagos

Seeds of 14 plant species extracted from food products proposed for field trips in Galapagos were tested for viability. Strawberry Fragaria ananasa and Blackberry Rubus glaucus jams (Snob and Gustadina brands) contained no viable seeds. Schullo brand granola contained inviable Sesame Sesamum indicum seed, but Sesame in granolas prepared in Galapagos was viable. Sesame seed in bread was viable but Flax Linum usitatissimum seed in bread was not. Brown Rice Oryza sativa and Sunflower seeds Helianthus annuus were both viable. Fresh Apple Malus domestica, Naranjilla Solanum quitoense, Cucumber Cucumis sativus, Pineapple Ananas comosus, Pear Pyrus communis, Bell Pepper Capsicum annuum, Tomato Solanum lycopersicum, Grape Vinis vinifera all contained viable seeds. We recommend prohibiting any product with viable seeds from field trips to uninhabited areas. CDF Contribution Number 1009.

Cholesterolgehalte in Fischereierzeugnissen vom Deutschen Markt

Kurzfassung Zahlreiche Fischereierzeugnisse aus dem Deutschen Handel wurden auf ihren Gehalt an Cholesterol hin analysiert. Zur Analyse gelangten 38 verschiedene Dauerkonserven von acht Fischarten, 4 Produkte kalt geräucherter Atlantischer Zuchtlachs in Scheiben, 10 Garnelenarten und 25 Fischstäbchenerzeugnisse von 5 Tierarten in Verbraucherpackungen. Bei den Dauerkonserven lagen die Gehalte zwischen 24 und 40 mg/100 g. Zwei Ausnahmen bildeten Sprottenkonserven mit durchschnittlich 107 mg/100 g und Oktopuskonserven mit 196 mg/100 g. Die Garnelenarten variierten zwischen 84 und 161 mg/100g. Die kalt geräucherten Lachsscheiben wiesen nur eine kleine Bandbreite im Cholesterolgehalt zwischen 38 und 43 mg/100 g auf. Alle Fischstäbchen aus Magerfischen enthielten niedrige Gehalte an Cholesterol (Pangasius hypophthalmus 25, Seehecht 19, Seelachs 31 und Alaska Seehecht 28 mg/100 g), während die zwei Proben aus Tintenfischen über 100 mg/100 g lagen. Abstract Numerous fishery products from the German market have been analysed for their content of cholesterol. In total 38 different canned fishery products produced from 8 species, 4 products of sliced cold smoked Atlantic salmon, 10 species of crustacean shellfish and 25 different brands of consumer packages of fish fingers (produced from 5 species) were investigated. Canned fishery products contained amounts of cholesterol ranging from 24 to 40 mg/100 g. However, canned sprats exhibit cholesterol content as high as 107 mg/100g and canned octopus 196 mg/100 g. Crustacean shellfish was found to contain cholesterol content between 84 and 161 mg/100 g depending of species. Sliced cold smoked salmon in 200 g consumer packages showed only a little variation in cholesterol content (38-43 mg/100 g). In all fish fingers produced from lean fish species low cholesterol content (pangasius or sutchi catfish 25, hake 19, saithe 31, and Alaska Pollack 28 mg/100 g, respectively) was found, whereas two products produced from squid exceeded 100 mg/100 g.