Effect of canned tuna fish processing steps on lead and cadmium contents of Iranian tuna fish

The contents of Pb and Cd in two species of Iranian tuna fish (yellowfin and skipjack), which were caught from the Persian Gulf and Oman Sea, and the effects of canning processing steps on their contents were assessed by electrothermal atomic absorption spectrometry. The results revealed that the levels of lead and cadmium throughout the processing steps in yellowfin were in range of 0.154 ± 0.019–0.441 ± 0.025 μg/g and 0.029 ± 0.002–0.084 ± 0.0005 μg/g, respectively. Pb and Cd concentrations from received fish to final product in skipjack were found to be in range of 0.072 ± 0.031–0.218 ± 0.031 μg/g and 0.016 ± 0.001–0.062 ± 0.002 μg/g, respectively. The limit of detection for lead and cadmium were 0.058 μg/g (11.6022 μg/l) and 0.0007 μg/g (0.1485 μg/l), respectively. Results from paired sample t-test analysis showed that defrosting, cooking, and sterilisation by autoclave would reduce the contents of lead and cadmium, considerably.     

Mercury,cadmium and lead content of canned tuna fish

Mercury levels in canned tuna fish were determined by cold vapour atomic absorption spectrophotometry while cadmium and lead levels were determined by flame atomic absorption spectrophotometry. The metal contents in the samples, expressed in μg g⁻¹ wet weight, varied from 0.20 to 0.66 with an average value of 0.29 for mercury, from 0.09 to 0.32 with an average value of 0.18 for cadmium and from 0.18 to 0.40 with an average value of 0.28 for lead. The results of this study indicate that tuna fish from the Mediterranean coast of Libya have concentrations well below the permissible levels for these toxic metals. Their contribution to the body burden can therefore be considered negligible.     

分光光度法测定鱼罐头中组胺的方法改进

在GB/T 5009.45-2003国家标准方法的基础上对样品的前处理等过程进行了新的尝试,使样品前处理过程简单、快速,同时保证了方法的准确度和精密度.结果显示,在60℃水浴、30 min条件下,三氯乙酸的提取效果最佳;正戊醇提取过程采用旋涡后离心的方式代替了分液漏斗振摇,获得了较佳的提取效果;盐酸提取液改为1.0 mL,保证了标准系列与测定系列显色体系的一致性,同时保证了实验结果的准确度.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Ultrasensitive flow-injection electrochemical method for determination of histamine in tuna fish samples

Histamine is a potentially hazardous compound and one of the major concerns in food chemistry. High amount of histamine may be found in food as a consequence of the use of poor quality raw materials, contamination and inappropriate conditions during food processing and storage. A novel method for the determination of histamine in flow-injection systems has been developed for use in seafood quality inspection and food quality control laboratories. The developed technique is very simple, precise, accurate, time saving and economic as compared to all of the previously reported methods. The effects of various parameters on the sensitivity of the method were investigated. The best performance was obtained with the conditions, pH value of 2.0, and sweep rate value of 40 V/s, accumulation potential of 900 mV and accumulation time of 0.4 s. In this work, we introduce a special computer based numerical method, for calculation of the analyte signal and noise reduction. The electrode response was calculated based on partial and total charge exchanges at the electrode surface after subtracting the background current from noise. The waveform potential consisting of potential steps for cleaning and accumulation of analyte, and potential ramp was applied on an Au disk microelectrode (with a radius of 12.5 μm). The method was linear over the concentration range of 1.1–5555 pg/ml (r = 0.998) with a limit of detection and quantification 0.35 and 1.16 pg/ml, respectively.     

Biological value of protein from raw fish and canned fish

The authors evaluated the nutritive value of protein from 4 kinds of raw fish (herring, cod, mackerel, sprat) and its preserves. Experiments were made on rats fed the diets containing fish protein (8-10% of the total diet). Experiments included the determination of apparent and genuine digestibility, net protein utilization, and net dietary protein caloric value. Evidence was obtained that protein from fish and its preserves is characterized by high digestibility coefficient as compared with casein and egg powder. The highest net protein utilization was noted in animal groups fed the diet containing protein from raw fish. Protein assimilability from fish preserves was on the average 15% lower than that from raw fish.     

Formation of histamine and biogenic amines in cold-smoked tuna: an investigation of psychrotolerant bacteria from samples implicated in cases of histamine fish poisoning

Two outbreaks and a single case of histamine fish poisoning associated with cold-smoked tuna (CST) were reported in Denmark during 2004. The bacteria most likely responsible for histamine formation in CST implicated in histamine fish poisoning was identified for the first time in this study. Product characteristics and profiles of biogenic amines in the implicated products were also recorded. In the single poisoning case, psychrotolerant Morganella morganii-like bacteria most likely was responsible for the histamine production in CST with 2.2% +/- 0.6% NaCl in the water phase (WPS). In outbreak 1, Photobacterium phosphoreum most likely formed the histamine in CST with 1.3% +/- 0.1% WPS. In outbreak 2, which involved 10 persons, the bacteria responsible for histamine formation could not be determined. The measured concentrations of WPS were very low compared with those of randomly collected commercial samples of CST and cold-smoked blue marlin (4.1 to 12.7% WPS). Challenge tests at 5 degrees C with psychrotolerant M. morganii and P. phosphoreum in CST with 4.4% WPS revealed growth and toxic histamine formation by the psychrotolerant M. morganii-like bacteria but not by P. phosphoreum. In a storage trial with naturally contaminated CST containing 6.9% WPS, lactic acid bacteria dominated the microbiota, and no significant histamine formation was observed during the shelf life of about 40 days at 5 degrees C and of about 16 days at 10 degrees C. To prevent toxic histamine formation, CST should be produced with >5% WPS and distributed with a declared 5 degrees C shelf life of 3 to 4 weeks or less.     

鱼类罐头相关食品标准法规中组胺指标探讨

目的探讨鱼类罐头相关食品标准法规中组胺指标,为GB 7098—2015《食品安全国家标准罐头食品》中鱼类罐头组胺指标修订提供基础数据。方法整理分析国内外法规情况、我国水产品及其制品组胺中毒情况,统计分析广东省市售高组胺鱼类罐头中组胺含量、广东省成人居民鱼类罐头消费量数据及组胺参考限量值。结果我国的鱼类罐头(仅适用于鲐鱼、鲹鱼、沙丁鱼罐头)组胺限量标准为1 000 mg/kg,高于国际组织和国外的组胺限量标准;1998—2018年我国水产品及其制品组胺中毒报道案例共18例,引起组胺中毒食物检测含量最低为120 mg/kg,最高为3 820 mg/kg;广东省主要鱼类罐头生产地区采集鱼类罐头样品136份,组胺含量范围为未检出(ND)～488.8 mg/kg,组胺含量超过200 mg/kg的占3.7%(5/136),超过400 mg/kg的占1.5%(2/136);基于广东省成人居民鱼类罐头高消费人群(P97.5)消费量为120 g/次和无作用剂量(NOAEL,50 mg)得出鱼类罐头组胺参考限量值为417 mg/kg。结论 GB 7098—2015鱼类罐头组胺指标限量值高,测定鱼品种少,建议我国开展高组胺鱼类罐头组胺风险评估,修订该标准鱼类罐头组胺指标。     

应用PCR-FINS技术鉴定金枪鱼罐头中金枪鱼种类

为考察金枪鱼罐头中DNA降解程度以及鉴定金枪鱼罐头中金枪鱼种类,文中根据鱼类线粒体基因组(m t DNA)细胞色素b(cyt b)基因和12S r DNA基因,利用3对通用引物分别扩增片段大小为358 bp(cyt b)、224bp(12S r DNA)、123bp(cyt b)的目的片段,同时,基于123 bp线粒体cytb基因片段,通过法医信息核苷酸测序(PCR-FINS)技术来鉴别金枪鱼罐头中金枪鱼的种类,并对17个市售金枪鱼罐头样品进行金枪鱼种类鉴定。结果表明:金枪鱼罐头中DNA降解严重,其片段大小在100~200 bp;该研究建立的PCR-FINS技术,可以实现金枪鱼罐头中金枪鱼种类的准确鉴别;17个市售金枪鱼罐头样品中,58.8%来源于价格低廉的鲣鱼,其次还包括长鳍金枪鱼、青干金枪鱼、扁鮀鲣、鲔鱼。     

Determination of phenolic antioxidants in tuna fillets canned in hydrosols with HPLC-DAD

Canned tuna was fortified with a mixture of brine and hydrosols of aromatic plants (i.e. oregano, laurel, sage and lemon balm). An HPLC-DAD method was developed and validated for the simultaneous determination of thirteen antioxidants in tuna fillets, including phenolic acids (gallic acid, vanillic acid, syringic acid and rosmarinic acid), flavonoids (catechin, epicatechin, vanillin, myricetin, rutin, quercetin, luteolin and apigenin) and one hydroxybenzaldehyde (syringaldehyde). The analytes showed satisfying recovery efficiency (82.1–92.1%), and the method presented excellent linearity (r² > 0.99). The precision limit was ≤5.6% RSD_r for intra-day and ≤7.2% RSD_R for inter-day experiments. The determined analytes ranged between 8.86 mg (quercetin) and 512 mg (rosmarinic acid) per 100g tuna flesh (n = 10), verifying that the hydrosols fortified the tuna fillets.     

Organochlorine pesticides in canned tuna and sardines on the Serbian market

The aim of this study was to determine the level of organochlorine (OC) pesticides in 57 samples of canned tuna and 31 samples of canned sardines in vegetable oil, collected from supermarkets in Serbia. OC pesticides α-HCH, β-HCH, δ-HCH, dichlorodiphenyltrichloroethane (DDT), DDE, DDD, dielderin, endosulfane I, endosulfane II, endosulan sulfate, endrin, endrin ketone, heptachlor, heptachlor epoxide, lindane, aldrin, metoxichlor, cis-chlordane and trans-chlordane were determined using a GS-MS method. The highest concentrations (µg kg^?1, arithmetic means) in canned tuna were for δ-HCH (60.6 ± 97.0) and p, p´-DDT (55.0 ± 25.1), while the corresponding values in canned sardines were for δ-HCH (90.7 ± 102.7) and endosulfane II (78.0 ± 145.9). Mean level for the sum of endosulfans was above the maximum limit in canned sardines (85.0 µg kg^?1). Also, dieldrin (39.7 µg kg^?1) was measured above the ML.     

Furan in canned sardines and other fish

Thirty-seven different samples of canned sardines and other fish sold in the United Kingdom were analysed for their furan content using a validated automated headspace gas chromatography–mass spectrometry procedure. All 37 samples contained detectable furan, with an average level of 26 μg kg^?1. The maximum furan content was in canned fish containing tomato sauce, which had an average of 49 μg kg^?1 and in canned fish packed with lemon which had an average of 55 μg kg^?1. All fish in brine or in oil contained less than 20 μg kg^?1 furan. Furan levels recorded in fish packed in extra virgin olive oil were low with an average of 2 μg kg^?1.     

Kinetics of thermal degradation of thiamine and surface colour in canned tuna

Summary The kinetics of thermal degradation of thiamine and surface colour (lightness measured as Hunter L-value) in canned white tuna were determined using an unsteady-state experimental procedure. Kinetic parameters were calculated by weighted non-linear regression considering a first-order kinetic model with a dependence of the kinetic coefficient (D) with temperature of the Thermal Death Time (TDT) type. Mass-average retentions of thiamine were calculated using a mathematical model which takes into account the non-uniform and unsteady distribution of temperature inside the container during thermal processing. The high correlation obtained between the predicted and the observed retention values and the small confidence intervals found for the kinetic parameters indicate a high statistical reliability. The kinetic model thus determined permits the simulation and optimization of the process resulting in a better quality of the final product.

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Kinetik des Abbaus von Thiamin und der Oberflächenfarbe von Dosenthunfisch

Zusammenfassung Die Kriterien der Wärmedegradation von Thiamin und der Oberflächenfarbe (Messung der Helligkeit mit dem Hunter-Wert L) in Konserven mit weißem Thunfisch werden mittels eines experimentellen Vorgehens von nicht-stationärem Typ bestimmt. Die kinetischen Parameter werden mit nicht-linearer, beschwerter Regression kalkuliert, wobei man einen kinetischen Koeffizienten D mit der Temperatur des Typs TDT bedenken muß. Für die Berechnung der durchschnittlichen Massenerhaltung von Thiamin benutzt man ein mathematisches Modell, das die nicht-uniforme und nichtbeständige Verteilung der Temperatur im Behälter während des Prozesses berücksichtigt. Die erhaltene starke Wechselbeziehung zwischen den vorhergesagten und den beobachteten Werten und zwischen den geringen Konfidenz-Intervallen, die für die kinetischen Parameter gefunden wurden, belegt eine hohe statistische Zuverlässigkeit. Das so bestimmte kinetische Modell erlaubt es, den Prozeß zu simulieren und zu optimieren, mit dem Ziel, die endgültige Qualität des Produktes zu verbessern.

     

Polychlorinated biphenyls in fresh and canned fish from the Central Adriatic.

By using the GLC method, levels of polychlorinated biphenyls (PCBs) were determined in fresh and canned fish during the 1984-88 period. Forty-six samples of fish caught in the Central Adriatic's littoral, 11 of which in a control, non-industrialized area, and 35 in an urbanized area strongly affected by industry, were collected. Also, 101 samples of canned fish were tested for PCBs. The average PCB values were 0.059 mg kg-1 and 0.287 mg kg-1 in control and polluted areas, respectively; the mean value in canned fish was 0.194 mg kg-1. Although the levels of PCBs in control and industrialized areas were found to differ, the difference was not significant statistically.     

A rapid dipstick test for histamine in tuna

This study describes the production of a solid phase assay (dipstick test) for histamine in tuna based on the coupling of diamine oxidase to a peroxidase/dye system. The optimized dipstick preparation consisted of a diamine oxidase/peroxidase/Stabilcoat mixture layered onto a tetramethylbenzidine color strip. The assay was linear to 1.0 mM histamine (RSQ = 0.994) and the minimum detectable concentration was 0.07 mM corresponding to 2.3 mg% in tuna extracts. Quality control samples gave intra and interassay precisions of 9.14–9.84 %CV and 7.08–13.86 %CV respectively. Similarly, the assay was accurate (p> 0.05) for both low and high controls. Histidine and cadaverine did not interfere with the assay whereas putrescine reacted slightly with the dipstick. Histamine determinations of fresh and spoiled tuna gave good agreement between the dipstick method and both the official reference and modified AOAC flurometric methods.     

Quality assessment of edible vegetable oils used as liquid medium in canned tuna

An experimental investigation was conducted to assess the quality of vegetable oils used as liquid medium in preserved fish. Sixteen tuna preserves were tested, including two in extra virgin olive oil, nine in olive oil (refined olive oil plus virgin olive oil) and five in refined seed oil. Next to the traditional routine analyses prescribed by the EEC Regulation N° 2568/91 (useful for a preliminary characterisation of oils used as liquid medium), the content of trans isomers of unsaturated fatty acids was determined and the analysis of polar compounds was performed by HPSEC (high performance size-exclusion chromatography). The acid composition showed the presence of highly unsaturated fatty acids, typical of fish lipids. Trans isomers were always absent in extra virgin olive oils, whereas they were always present in olive oils and in refined seed oils. Triglyceride oligopolymers, oxidised triglycerides and diglycerides, measured by means of the HPSEC analysis of polar compounds, ranged within 0.13-1.07%, 0.51-2.36% and 0.96-4.02%, respectively. The HPSEC analysis of polar compounds and the determination of trans isomers enabled better assessment of the quality of different types of oils used as liquid medium for canned tuna.     

Challenges in the identification of species of canned fish

The identification of fish species becomes a problem when the usual identifying characteristics are removed on processing and only a portion of flesh is available. When the flesh is raw or cooked under normal conditions, the species is readily established by electrophoresis of the muscle proteins. The procedure cannot be used for heat-sterilised canned fish as the proteins are severely denatured. DNA is also degraded but techniques are now available for targeting and amplifying species-specific fragments. The amplified products can then be analysed by a range of techniques some of which are suitable for food control laboratories.     

Lipid changes during long-term storage of canned tuna (Thunnus alalunga)

 In previous studies fluorescence detection at different excitation/emission maxima during common fish processing has been used. A bathochromic shift towards higher wavelength maxima was observed and measured as the ratio between absorption at two of the maxima tested. This fluorescence ratio (δF) value correlates positively with fish damage. In the present work, the influence of formaldehyde (FA) on the value δF was studied. A model system was set up in which FA reacted at 30°C for 25 days with propylamine and fish muscle. It was observed that FA was less able to produce fluorescent compounds compared with common fish oxidation products that were also tested, i. e. propanal and hexanal. However, in the presence of both lipid oxidation aldehydes, the FA-containing mixtures led to a higher δF value. Model systems consisting of FA and fatty fish (sardine) muscle produced more fluorescence than FA and lean fish (cod), because of the formation of lipid oxidation compounds under the reaction conditions of the former systems. It is thus concluded that the presence of FA in a reacting medium enhances fluorescence formation, such that δF be can used as an accurate measure of fish damage. It is thought that measurement of δF in processes such as the freezing of gadoid fish, in which both FA and lipid oxidation are produced, could be of benefit. Received: 23 June 1997     

Lipid changes during long-term storage of canned tuna (Thunnus alalunga)

 Lipid damage during prolonged storage of canned fish was studied. Albacore tuna was processed under two sterilization conditions (115°C, 74 min; 120°C, 40 min) and then stored for up to 6 years. Analyses (lipid oxidation and hydrolysis, browning and formation of fluorescent compounds) of the lipids extracted from the white muscle of the fish and the packing oils were carried out. Muscle lipids were partially extracted by the packing oil, so that an increase in the storage time produced higher levels of free fatty acids, browning and fluorescence development in the packing oils. As regards the types of muscle, little difference between them throughout the canned storage was detected. Received: 17 February 1997 / Revised version: 12 May 1997