Variation in Shrimp Allergens: Place of Origin Effects on Food Safety Assessment.

Due to the widespread use of shellfish ingredients in food products, accurate food labelling is urgently needed for consumers with shellfish allergies. Most crustacean allergen detection systems target the immunorecognition of the allergenic protein tropomyosin. However, this mode of detection may be affected by an origin-dependent protein composition. This study determined if the geographic location of capture, or aquaculture, influenced the allergenic protein profiles of Black Tiger Shrimp (Penaeus monodon), one of the most farmed and consumed shrimp species worldwide. Protein composition was analysed in shrimp from nine different locations in the Asia-Pacific by SDS-PAGE, immunoblotting, and mass spectrometry. Ten of the twelve known shrimp allergens were detected, but with considerable differences between locations. Sarcoplasmic calcium-binding protein, myosin light chain, and tropomyosin were the most abundant allergens in all locations. Hemocyanin-specific antibodies could identify up to six different isoforms, depending on the location of origin. Similarly, tropomyosin abundance varied by up to 13 times between locations. These findings suggest that allergen abundance may be related to shrimp origin and, thus, shrimp origin might directly impact the readout of commercial crustacean allergen detection kits, most of which target tropomyosin, and this should be considered in food safety assessments.

Exposure assessment to paralytic shellfish toxins through the shellfish consumption in Korea.

Paralytic shellfish poisoning is caused by saxitoxin and its analogues. The paralytic shellfish toxins (PSTs) are produced by marine dinoflagellates and can be accumulated in filter feeding shellfish, such as mussel, clam, oyster and ark shell. The worldwide regulatory limits for PSTs in shellfish are set at 80 µg STX eq./100 g meat and this is widely accepted as providing adequate public health protection. In this study, we have determined five individual PSTs (STX, GTX1, GTX2, GTX3 and GTX4) in shellfish using LC-MS/MS and assessed the human acute and chronic exposures to PSTs through shellfish consumption. Food consumption data was obtained from the Korea National Health and Nutrition Examination Survey (KNHANES 2010-2015). The acute exposure using a large portion size of 88 g/day (95th percentile for consumers only) with maximum toxin level of 198.7 µg/kg was 0.30 µg/kg bw. Even though we estimated the acute exposure with a conservative manner, it was below the ARfDs (0.5 or 0.7 µg STX eq./kg bw) proposed by the international organizations, representing 43-60% of the ARfDs. The chronic exposures using mean consumption data for whole population with mean concentration of PSTs were ranged from 0.002 to 0.026 µg STX eq./kg bw/day. For consumers only, the chronic exposures were in the range of 0.012-0.128 µg STX eq./kg bw/day.

Bioaccumulation of Heavy Metals in Various Tissues of Some Fish Species and Green Tiger Shrimp (Penaeus semisulcatus) from Iskenderun Bay, Turkey, and Risk Assessment for Human Health.

In this study, concentrations of heavy metals were determined by ICP-MS in the edible tissues of common sole (Solea solea Linnaeus, 1758), whiting (Merlangius merlangus Linnaeus, 1758), silver sillago (Sillago sihama Forsskål, 1775) and muscle-exoskeleton of green tiger shrimp (Penaeus semisulcatus De Haan, 1844), from the seas of Iskenderun Bay, Eastern Mediterranean, Turkey, in January-February, 2016. The lowest and highest mean concentrations of Mn, Cr, Cd, Ni, Hg, As, Pb, and Co in fish and shrimp' muscles were found, respectively, as follows: 0.166-0.382, 0.134-0.336, 0.005-0.008, 0.091-0.140, 0.026-0.228, 1.741-29.254, 0.087-0.110, and <0.0005-0.027 mg kg-1; in the skin and exoskeleton, the values were found, respectively, as 0.103-15.819, 0.301-0.778, 0.007-0.026, 0.115-0.513, 0.021-0.243, 1.548-17.930, 0.148-0.295, and <0.0005-0.140 mg kg-1. According to the results, mean concentrations of all metals in the muscles of fish, except for arsenic and chromium, were found to be below certain legal limit values, especially arsenic levels in shrimp that were found to be above all the legal limit values. Also, the hazard quotients (HQ) of individual heavy metals in fish and shrimp, except for As, revealed safe levels for human consumption. However, the HQ values of estimated inorganic As exceeded 1 in the muscles of shrimp (P. semisulcatus), which may constitute a risk to public health.

Prevalence of Vibrio parahaemolyticus in seafood products from hypermarkets in Shanghai.

BACKGROUND: Vibrio parahaemolyticus is an important gastroenteritis pathogen contaminating seafood in China. In this study a total of 992 seafood samples from major hypermarkets in Shanghai were monitored for prevalence and burden of V. parahaemolyticus from January 2011 to December 2012. Additionally, appropriate probability distributions for describing V. parahaemolyticus concentrations were assessed based on these surveillance data. RESULTS: Seventeen of 992 samples were positive for V. parahaemolyticus and the geometric mean was 0.1581 most probable number (MPN) g-1 . The variation in prevalence of V. parahaemolyticus was seasonal and the burden of contamination in August (0.1942 MPN g-1 ) was significant (P < 0.01) between 2011 and 2012. Also, the prevalence of V. parahaemolyticus was higher in shellfish and cephalopods than in other seafood (P < 0.05). By comparison, the lognormal distribution and integrated distribution showed no obvious difference for characterizing V. parahaemolyticus contamination. CONCLUSION: The low prevalence and burden found indicated that seafood from hypermarkets may not be an important risk source for V. parahaemolyticus infection in Shanghai, and more attention should be paid to other areas for selling seafood, such as farmlands or farmers' markets. The simple and effective lognormal distribution is recommended as a better choice for describing V. parahaemolyticus contamination in future risk assessment studies. © 2016 Society of Chemical Industry.

Noninvasive assessment of liver stiffness by transient elastography (FibroScan) in liver fluke disease.

AIM: Transient elastography is a noninvasive and reliable method for the assessment of liver stiffness. This study aimed to assess liver stiffness of asymptomatic liver fluke disease patients by FibroScan and evaluate the factors influencing liver stiffness. METHODS: Overall, 65 patients were prospectively recruited from The First People's Hospital of Foshan, Guangdong, China. All patients were diagnosed with liver fluke disease; their durations of ingested freshwater raw fish or shrimp were more than 10 years, and none of them had abnormal liver function and hepatitis B virus or hepatitis C virus infection, or clinical symptoms. All patients underwent FibroScan, blood biochemical examination, and BMI measurement on the same day. Liver stiffness measurement (LSM) values, sex, age, durations of ingested freshwater raw fish or shrimp, and BMI were recorded. LSM value greater than 7.4 kPa was defined as abnormal. RESULTS: A total of 27 patients (41.5%) had abnormal LSM values. On partial correlation analysis, duration of ingested freshwater raw fish or shrimp was the independent factor that showed a positive correlation with abnormal LSM values (r=0.502, P=0.012). An independent-samples t-test showed that the durations of patients with abnormal LSM values were significantly longer than the durations of patients with normal LSM values (P<0.001). Sex, age, and BMI were not significantly correlated with LSM values (P>0.05). CONCLUSION: A high proportion of asymptomatic liver fluke disease patients had abnormal LSM values. The durations of patients with abnormal LSM values were significantly longer than the durations of patients with normal LSM values and the durations of patients with abnormal LSM values were an independent factor that showed a positive correlation with abnormal LSM values.

Epidemiological evidence of lesser role of thermostable direct hemolysin (TDH)-related hemolysin (TRH) than TDH on Vibrio parahaemolyticus pathogenicity.

Vibrio parahaemolyticus carrying the tdh gene, encoding the thermostable direct hemolysin (TDH), or the trh gene, encoding the TDH-related hemolysin (TRH), are both considered virulent strains. There are, however, disproportionally fewer reports of infections caused by seafood contaminated with trh-positive strains than by seafood contaminated with tdh-positive strains. Bivalves such as clams and oysters are the major seafood varieties associated with the infections. In this study, the prevalence of strains possessing the tdh and trh genes was investigated in Japan in 74 samples collected in 2007-2008 and in 177 samples collected in 2010 of domestic bivalves, bloody clams, hen clams, short-neck clams, and rock oysters. The tdh-positive and trh-negative, tdh-negative and trh-positive, and tdh-positive and trh-positive samples represented 5.4%, 12.2%, and 4.1% of all samples collected in 2007-2008, and 5.1%, 18.6%, and 5.6% of all samples collected in 2010, respectively. As determined by polymerase chain reaction, the prevalence of tdh negative and trh positive in all samples was two to four times higher than that of tdh positive and trh negative. In the samples collected in 2010, the tdh-negative and trh-positive V. parahaemolyticus (20 samples) was more often isolated than tdh-positive and trh-negative V. parahaemolyticus (7 samples). The most common serotype of tdh-positive isolates (22 of 24 strains) was pandemic O3:K6. The trh-positive isolates (61 strains) were various serotypes including OUT:KUT. In 330 V. parahaemolyticus outbreaks and sporadic infections in Japan, most outbreaks and sporadic infections were caused by tdh-positive and trh-negative strains (89.4%). The frequencies of infections caused by tdh-negative and trh-positive, and both tdh- and trh-positive strains were 1.2% and 3.0%, respectively. This finding suggests that the virulence of trh might be less than that of tdh, although trh-positive V. parahaemolyticus frequently contaminated bivalves.

Mercury contamination and exposure assessment of fishery products in Korea.

In this study, total (T-Hg) and methyl mercury (Me-Hg) contamination was investigated in fishery products including canned fish, fish sauces, dried bonito and frozen tuna sashimi, collected from retail markets in Korea, to assess dietary exposure. Direct mercury analyser and gas chromatography-electron captured detector were employed to measure T-Hg and Me-Hg, respectively. The highest T-Hg and Me-Hg contamination was present in tuna sashimi, followed by dried bonito, respectively. Canned tuna showed more frequent detection and higher content than other canned fishery products. The weekly exposure estimate indicates that exposure to mercury from fishery products is safe, showing 2.59% provisional tolerable weekly intake (PTWI) for T-Hg, 1.82% PTWI for Me-Hg and 4.16% reference dose for Me-Hg. However, it should be addressed to monitor the mercury contamination in fish and fishery products regularly, to safeguard vulnerable population such as children, to limit intake of these food products.

Undeclared allergenic ingredients in foods from animal origin: survey of an Italian region's food market, 2007-2009.

Several EC Directives have been promulgated to protect allergic individuals but no rule has been established with regard to allergen cross-contamination caused by shared transport vehicles or common processing equipment. The aim of this research was to quantify, by enzyme-linked immunosorbent assay (ELISA) or real-time polymerase chain reaction, the presence in meat- or fish-based foods of four allergens (milk, egg, crustaceans and molluscs) that was not indicated either in the list of ingredients or in the label alert. In the time frame of 2007-2009, a total of 723 samples were subjected to 1983 analyses. The percentage of samples scoring positive ranged between 1.8% and 6.8% over the 3 years, and the concentrations of undeclared allergens found were 0.3-13.3 mg kg⁻¹ for milk (ß-lactoglobulin) and 0.21-12 mg kg⁻¹ for egg white proteins. On this basis, the possibility of cross-contamination serious enough to raise public health concern cannot be dismissed.

Mercury, cadmium and lead levels in samples of the main traded fish and shellfish species in Galicia, Spain.

The presence of mercury, cadmium and lead has been studied in raw and processed fish and shellfish of the main traded species in Galicia (Spain) from at least 40 commercial outlets between January 2002 and October 2003. The results show that, according to European legislation, the products on the market are generally "safe", although the high levels of mercury in swordfish and shark are notable, with 22% of samples (n = 37) over the limit. We also indicate the relatively important contribution to mercury ingestion of widely consumed species, such as tuna, with 25% of samples (n = 378) over 0.25 mg kg⁻¹. Cadmium was over the limit (1.0 mg kg⁻¹) in 15% of the tested cephalopods (n = 79) and 29% of Chlamys sp. bivalves (n = 17).

Monitoring programme on cadmium, lead and mercury in fish and seafood from Valencia, Spain: levels and estimated weekly intake.

The study was carried out to determine the current levels of mercury, cadmium, and lead in fish and seafood from the market of Comunitat Valenciana, Spain. Levels of total mercury ranged from 0.02 to 3.15 mg kg⁻¹ w.w. (average = 0.073 mg kg⁻¹ w.w.). Cadmium concentrations ranged from 0.003 to 0.66 mg kg⁻¹ w.w. (average = 0.27 mg kg⁻¹ w.w.) for seafood, and between 0.003 and 0.71 mg kg⁻¹ w.w. (average = 0.01 mg kg⁻¹ w.w.) for marine fish. Concerning lead, concentrations from 0.02 to 0.36 mg kg⁻¹ w.w (average = 0.04 mg kg⁻¹ w.w.) were found in fish, and from 0.02 to 1.02 mg kg⁻¹ w.w. in seafood (average = 0.147 mg kg⁻¹ w.w.). The levels found were, in general, lower than maximum levels proposed by European legislation. The estimated weekly intake of mercury, cadmium and lead through fish and seafood consumption was found to be about 43%, 10% and 3% of the established provisional tolerable weekly intake, respectively.

Dietary intake estimations of polybrominated diphenyl ethers (PBDEs) based on a total diet study in Osaka, Japan.

This study presents the results of a total diet study performed for estimating the dietary intake of polybrominated diphenyl ethers (PBDEs) in Osaka, Japan. The concentrations of 36 PBDEs were measured in samples from 14 food groups (Groups I-XIV). PBDEs were detected only in Groups IV (oils and fats), V (legumes and their products), X (fish, shellfish, and their products), and XI (meat and eggs) at concentrations of 1.8, 0.03, 0.48, and 0.01 ng g⁻¹, respectively. For an average person, the lower bound dietary intakes of penta- and deca-formulations were estimated to be 46 and 21 ng day⁻¹, respectively. A high proportion of the decabrominated congener (DeBDE-209) was observed in Group IV. To confirm the presence of DeBDE-209 in vegetable oils, an additional analysis was performed using 18 vegetable oil samples. Of these, seven contained ng g⁻¹ levels of DeBDE-209.

Isolation of Prorocentrum lima (Syn. Exuviaella lima) and diarrhetic shellfish poisoning (DSP) risk assessment in the Gulf of California, Mexico.

A benthic toxic dinoflagellate identified as Prorocentrum lima (Syn. Exuviaella lima), and designated as strain PRL-1, was isolated from the coast of El Pardito (Coyote) Island in Baja California Sur, Mexico, after a fisherman poisoning incident involving consumption of liver from Lutjanus colorado, and Mycteroperca prionura fish. Purification and culturing was done in ES-Si medium, under 12:12 light/dark cycle (4 x 20 W cool-white fluorescent lamps), at 22 degrees C and constant stirring during 28 days. Whole cells were toxic to Artemia franciscana and its methanolic extract to mouse and to the marine yeast Debaryomyces hansenii. Chromatographic analysis (TLC and HPLC-MS) of such extract indicated an unusual proportion (1:2) okadaic acid (OA) and dinophysistoxin-1 (DTX-1). Estimated total toxin content by mouse bioassay (based on OA toxicity) was 19 pg/cell, a value significantly higher than that found by HPLC-MS (about 5.2 pg/cell, taking into account OA and DTX-1 only), suggesting that additional toxic components of unidentified nature are detected with the bioassay. This is the first report of a successful isolation and culturing of a toxic dinoflagellate from the Gulf of California, Mexico.