AIM: To improve the efficacy of intercalating dyes to distinguishing between infectious and inactivated hepatitis A virus (HAV) in food. METHODS AND RESULTS: Different intercalating dyes were evaluated for the discrimination between infectious and thermally inactivated HAV suspensions combining with the RT‐qPCR proposed in the ISO 15216. Among them, PMAxx was the best dye in removing the RT‐qPCR signal from inactivated HAV. Applied to lettuce and spinach, PMAxx–Triton pretreatment resulted in complete removal of the RT‐qPCR signal from inactivated HAV. Likewise, this study demonstrates that this pretreatment is suitable for the discrimination of inactivated HAV in shellfish without further sample dilution. In mussels and oysters, the developed viability RT‐qPCR method reduced the signal of inactivated HAV between 1·7 and 2·2 logs at high inoculation level, and signal was completely removed at low inoculation level. CONCLUSIONS: This study showed that the use of PMAxx is an important improvement to assess HAV infectivity by RT‐qPCR. It was shown that PMAxx–Triton pretreatment is suitable for the analysis of infectious HAV in complex food samples such as vegetables and shellfish. SIGNIFICANCE AND IMPACT OF THE STUDY: The PMAxx–Triton pretreatment can be easily incorporated to the ISO norm for infectious virus detection.

A novel method was used to estimate assimilation efficiencies (AEs) of dissolved and food associated PCBs (IUPAC 31, 49, and 153) by the Baltic Sea blue mussel (Mytilus edulis). Mussels were exposed to radiolabeled PCBs in a series of short-term toxicokinetic experiments at different algal food concentrations, both at apparent steady-state (ASS) and non-steady-state (NSS) conditions in respect to PCB partitioning between water and algae. The PCB AEs were calculated using a physiologically based bioaccumulation model where experimentally determined uptake and exposure rates at ASS and NSS conditions were combined into linear equation systems, which were solved for PCB AE from water and food. A positive relationship between PCB uptake and algae clearance by the mussels was observed for all three PCBs. The PCB AEs from both water and food increased with congener hydrophobicity (octanol/water partition coefficient [K(ow)]), but AEs decreased with increases in water pumping and filtration rate of the mussels, respectively, The average contribution of food-associated PCB to the total uptake also increased with K(ow) from approximately 30% for PCB 31 and PCB 49 to 50% for PCB 153, mainly as a consequence of increased sorption to the algal food.

Aquaculture, which is growing 3–5 times faster than terrestrial agriculture, will play an important role to meet future global food production needs. However, over 80% of global sewage production is returned to the environment untreated or poorly treated. In developing nations, these nontraditional waters of diverse quality are being recycled for aquaculture, yet chemical residues are differentially studied. Here, we examined pharmaceuticals, pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and flame retardants in marine bivalves using isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and low-pressure gas chromatography-tandem mass spectrometry (LP GC-MS/MS). Green-lipped mussels from the field and oysters from aquaculture net pens, which are harvested as food products, were collected adjacent to point source municipal wastewater and landfill leachate effluent discharges, respectively, in Hong Kong, the fourth most densely populated country in the world. Multiple classes of pharmaceutical, pesticides, PAHs, and phosphorus-based flame retardants were detected at low μg/kg levels. Acceptable servings per week indicated minimal risk for a number of chemicals; however, such calculations could not be performed for other contaminants of emerging concern. Future efforts are needed to better understand contaminant influences on marine bivalve populations and aquaculture product safety, particularly in rapidly urbanizing regions of developing countries with limited wastewater infrastructure.

L'impact de la moule mediterraneenne (Mytilus galloprovincialis Lamarck) sur les flux de matiere particulaire dans la colonne d'eau a ete mesure au laboratoire pour differentes vitesses de courant. Les experiences en laboratoire dans un canal a courant montrent qu'a 20 degres C, le taux de filtration augmente avec la vitesse de courant jusqu'a des vitesses de courant de 20 a 25 cm/s. Le taux de filtration reste semblable a 26 degres C. Lorsque la concentration phytoplanctonique dans la colonne d'eau est elevee (8 500-11 000 cell/mL de Cryptomonas sp., Cryptophyceae), les taux de filtration sont faibles (0,2 0,4 L/h pour un individu standard de 1 g de poids sec). Des taux de filtration plus eleves (0,5-2,5 L/h pour un individu standard) sont observes avec des concentrations phytoplanctoniques plus faibles (1 300-5 800 cell/mL de Prorocentrum minimum, Dinophyceae). Ainsi, les taux de filtration mesures pour Mytilus galloprovincialis varient avec la charge phytoplanctonique et avec la vitesse du courant. Ces resultats suggerent que les moules mediterraneennes, provenant d'un milieu ou les variations de charges sestoniques et de vitesses de courant sont de grande amplitude, ont de grandes capacites d'adaptation