Detoxification of paralytic shellfish poisoning toxins in naturally contaminated mussels, clams and scallops by an industrial procedure

Abstract

Paralytic shellfish poisoning (PSP) episodes cause important economic impacts due to closure of shellfish production areas in order to protect human health. These closures, if are frequent and persistent, can seriously affect shellfish producers and the seafood industry, among others. In this study, we have developed an alternative processing method for bivalves with PSP content above the legal limit, which allows reducing toxicity to acceptable levels. A modification of the PSP detoxifying procedure stablished by Decision 96/77/EC of the European Union in Acanthocardia tuberculatum, was developed and implemented for PSP elimination in other species of bivalves. The procedure was applied to 6 batches of mussels, 2 batches of clams and 2 batches of scallops, achieving detoxification rates of around 85%. A viable industrial protocol which allows the transformation of a product at risk into a safe product was developed. Although a significant reduction was obtained, in a sample circa 9000 µg STX diHCl equiv/kg, the final toxin level in these highly toxic mussels did not fall below the European limit. The processing protocol described may be applied efficiently to mussels, clams and scallops and it may be a major solution to counteract the closure of shellfish harvesting areas, especially if persistent. Highlights  An industrial protocol aimed at reducing PSP toxin levels was developed and optimized in mussels, clams and scallops.  The procedure was applied to some batches of PSP-contaminated molluscs obtaining ± 85 % detoxification and a safe product.  However, one sample with an exceptionally high toxicity, 9000 µg STX diHCl equiv/kg, did not fall below the European limit.  An economically feasible bivalve canning processing was implemented, guaranteeing the manufacture of a safe product.

Paralytic Shellfish Toxins in the Gastropod Concholepas concholepas: Variability, Toxin Profiles and Mechanisms for Toxicity Reduction

“…To date, different mechanisms of detoxification of paralytic toxins in bivalve molluscs have been described as reducing toxicity to a value below the permissible limit for human consumption, including evisceration, freezing and high temperature processes [ 55 , 56 , 57 , 58 ]. In certain products, such as the scallop Pecten maximus , the combination of evisceration and thermal processing produces a decrease of toxicity from 300 μg to values below the detection limit [ 56 ].…”

“…As a result, evaluations of the effect of freezing on the concentration and toxicological profile are necessary. Freezing is a process rarely used in the canning industry since the decrease of toxins via this method is lower and occurs via their elimination through the thawing water [ 56 ]. In this study, the freezing process does not show a significant effect on decreasing toxicity when analysed using the MBA technique, but it does produce interesting findings by means of the PCOX technique on individuals extracted from the Guaitecas Archipelago.…”

“…In addition, freezing does not change the toxicological profile of the product and saxitoxin remains dominant therein (data not shown). This is different in high-temperature thermal processes, whereby there is transfer of toxins from the meat to the covering liquid, and, consequently, a transformation in the toxicological profile occurs [ 55 , 56 , 57 , 58 ].…”

An Occurrence and Exposure Assessment of Paralytic Shellfish Toxins from Shellfish in Zhejiang Province, China

“…To protect human health, various technologies have been applied to reduce PST contamination in samples, but no method has been shown to effectively eliminate PSTs [29], which results in either the incomplete elimination of PSTs or the generation of toxic byproducts. For example, PSTs are heat-stable; therefore, home processing (cooking and steaming) usually fails to destroy PSTs completely when eating chowder [4], and cooking cannot change the high bioaccessibility of PSTs in shellfish [6].…”

Short Depuration of Oysters Intended for Human Consumption Is Effective at Reducing Exposure to Nanoplastics

“…Understanding the kinetics of NP depuration is fundamental to understand whether oysters eliminate NPs through egestion (and thus reduce human exposure), or whether they stay in the organism and accumulate in various organs or tissues, similar to what happens with bivalves and other particle types such as microplastics (e.g., Ward et al), other synthetic particles (e.g., Rosa et al), or particles naturally present in the marine environment (e.g., Cognie et al). Such information can be used to mitigate the risk(s) of consuming NPs through the optimized depuration of shellfish, similar to toxin and pathogen elimination from bivalves (e.g., Cabado et al, O’Mahony, Gyawali et al). Uptake, accumulation, and depuration mechanisms of NPs in bivalves are not fully understood.…”