First Survey about Current Practices of Environmental Monitoring Programs within French Agri-Food Industries.

Food safety is a constant challenge for stakeholders in the food industry. To manage the likelihood of microbiological contamination, food safety management systems must be robust, including food and environmental testing. Environmental monitoring programs (EMP) have emerged this last decade aiming to validate cleaning-sanitation procedures and other environmental pathogen control programs. The need to monitor production environments has become evident because of recent foodborne outbreaks. However, the boundaries of environmental monitoring are not only limited to the management of pathogens but also extend to spoilage and hygiene indicators, microorganisms, allergens, and other hygiene monitoring. Surfaces in production environments can be a source of contamination, either through ineffective cleaning and disinfection procedures or through contamination during production by flows or operators. This study analyses the current practices of 37 French agri-food industries (small, medium, or large), reporting their objectives for EMPs, microbial targets, types, numbers and frequency of sampling, analysis of results, and types of corrective actions.

Health risk assessment related to pinnatoxins in French shellfish.

Pinnatoxins (PnTXs) are a group of emerging marine biotoxins produced by the benthic dinoflagellate Vulcanodinium rugosum, currently not regulated in Europe or in any other country in the world. In France, PnTXs were detected for the first time in 2011, in mussels from the Ingril lagoon (South of France, Mediterranean coast). Since then, analyses carried out in mussels from this lagoon have shown high concentrations of PnTXs for several months each year. PnTXs have also been detected, to a lesser extent, in mussels from other Mediterranean lagoons and on the Atlantic and Corsican coasts. In the French data, the main analog is PnTX G (low levels of PnTX A are also present in some samples). No cases of PnTXs poisoning in humans have been reported so far in France or anywhere else in the world. In mice, PnTXs induce acute neurotoxic effects, within a few minutes after oral administration. Clinical signs of toxicity include decreased mobility, paralysis of the hind legs, tremors, jumps and breathing difficulties leading to death by respiratory arrest at high doses. The French agency for food safety (ANSES) recently conducted a review of the state of knowledge related to PnTXs and V. rugosum. Based on (i) the clinical signs of toxicity in mice, (ii) the mode of action of PnTXs as nicotinic acetylcholine receptor competitive antagonists and (iii) knowledge on drugs and natural toxins with PnTX-related pharmacology, potential human symptoms have been extrapolated and proposed. In this work, a provisional acute benchmark value for PnTX G of 0.13 µg/kg bw per day has been derived from an oral acute toxicity study in mice. Based on this value and a large shellfish meat portion size of 400g, a concentration lower than 23 µg PnTX G/kg shellfish meat is not expected to result in adverse effects in humans. ANSES recommends taking into account PnTXs in the French official monitoring program for shellfish production and identified data gaps to refine health risk assessment.

Pinnatoxins' Deleterious Effects on Cholinergic Networks: From Experimental Models to Human Health.

Pinnatoxins (PnTXs) are emerging neurotoxins that were discovered about 30 years ago. They are solely produced by the marine dinoflagellate Vulcanodinium rugosum, and may be transferred into the food chain, as they have been found in various marine invertebrates, including bivalves. No human intoxication has been reported to date although acute toxicity was induced by PnTxs in rodents. LD50 values have been estimated for the different PnTXs through the oral route. At sublethal doses, all symptoms are reversible, and no neurological sequelae are visible. These symptoms are consistent with impairment of central and peripheral cholinergic network functions. In fact, PnTXs are high-affinity competitive antagonists of nicotinic acetylcholine receptors (nAChRs). Moreover, their lethal effects are consistent with the inhibition of muscle nAChRs, inducing respiratory distress and paralysis. Human intoxication by ingestion of PnTXs could result in various symptoms observed in episodes of poisoning with natural nAChR antagonists. This review updates the available data on PnTX toxicity with a focus on their mode of action on cholinergic networks and suggests the effects that could be extrapolated on human physiology.

Occurrence of ß-N-methylamino-l-alanine (BMAA) and Isomers in Aquatic Environments and Aquatic Food Sources for Humans.

The neurotoxin ß-N-methylamino-l-alanine (BMAA), a non-protein amino acid produced by terrestrial and aquatic cyanobacteria and by micro-algae, has been suggested to play a role as an environmental factor in the neurodegenerative disease Amyotrophic Lateral Sclerosis-Parkinsonism-Dementia complex (ALS-PDC). The ubiquitous presence of BMAA in aquatic environments and organisms along the food chain potentially makes it public health concerns. However, the BMAA-associated human health risk remains difficult to rigorously assess due to analytical challenges associated with the detection and quantification of BMAA and its natural isomers, 2,4-diamino butyric acid (DAB), ß-amino-N-methyl-alanine (BAMA) and N-(2-aminoethyl) glycine (AEG). This systematic review, reporting the current knowledge on the presence of BMAA and isomers in aquatic environments and human food sources, was based on a selection and a score numbering of the scientific literature according to various qualitative and quantitative criteria concerning the chemical analytical methods used. Results from the best-graded studies show that marine bivalves are to date the matrix containing the higher amount of BMAA, far more than most fish muscles, but with an exception for shark cartilage. This review discusses the available data in terms of their use for human health risk assessment and identifies knowledge gaps requiring further investigations.

Cellular and Molecular Aspects of the ß-N-Methylamino-l-alanine (BMAA) Mode of Action within the Neurodegenerative Pathway: Facts and Controversy.

The implication of the cyanotoxin ß-N-methylamino-l-alanine (BMAA) in long-lasting neurodegenerative disorders is still a matter of controversy. It has been alleged that chronic ingestion of BMAA through the food chain could be a causative agent of amyotrophic lateral sclerosis (ALS) and several related pathologies including Parkinson syndrome. Both in vitro and in vivo studies of the BMAA mode of action have focused on different molecular targets, demonstrating its toxicity to neuronal cells, especially motoneurons, and linking it to human neurodegenerative diseases. Historically, the hypothesis of BMAA-induced excitotoxicity following the stimulation of glutamate receptors has been established. However, in this paradigm, most studies have shown acute, rather than chronic effects of BMAA. More recently, the interaction of this toxin with neuromelanin, a pigment present in the nervous system, has opened a new research perspective. The issues raised by this toxin are related to its kinetics of action, and its possible incorporation into cellular proteins. It appears that BMAA neurotoxic activity involves different targets through several mechanisms known to favour the development of neurodegenerative processes.

Role of gut macrophages in mice orally contaminated with scrapie or BSE.

While there is a growing consensus on the understanding of the propagation pathways after oral infection of transmissible spongiform encephalopathy (TSE) agents and even if the central role of follicular dendritic cells is identified, little is known about the key players in the first steps of the infection and about the site of the disease development. We investigated the role of gut macrophages, which are capable of capturing aggregates of the prion protein. PLGA particles containing clodronate were designed in order to be orally administered and to target Peyer's patches for inducing gut-associated macrophages suicide in mice. Mice were subsequently infected with scrapie or BSE by the oral route. It was found that the efficacy of macrophage suppression in the Peyer's patches correlated well with an earlier appearance of PrPres in these formations and with a higher amount of PrPres at a later stage of the infection. Thus, the capture of infectious particles that have crossed the epithelial gut barrier and their elimination by macrophages seems to be a key event to restrict the amount of agent initiating the infection.

Pathogenesis of the oral route of infection of mice with scrapie and bovine spongiform encephalopathy agents.

Transmissible spongiform encephalopathies can be transmitted via the oral route. The understanding of this mode of contamination has become a major issue since it is responsible for the appearance of bovine spongiform encephalopathy (BSE) and is probably implicated in new variant Creutzfeldt-Jakob disease. In this study, we addressed the questions of the propagation pathway and the strain specificity of the pathogenesis of oral contamination of mice with the C506M3 scrapie strain and the 6PB1 BSE strain. PrPres was used as a marker of infectivity and was searched for sequentially in 22 organs during the whole incubation period and clinical stage. PrPres was first detectable in the Peyer's patches and mesenteric lymph nodes at 45 days post-inoculation. It became detectable 1 to 3 months later in the other tissues of the lymphoreticular system (LRS) such as the spleen and the lymph nodes not related to the digestive tract. These data indicate that after an oral route of entry, the infectious agent is propagated from the Peyer's patches to the mesenteric lymph nodes by the lymphatic route, then enters the bloodstream and is distributed to the secondary replication site, the LRS. The major difference between the two agents is that PrPres could be detected in the digestive tract (from the stomach to the colon) with the scrapie agent only. This observation may have implications for the horizontal transmission of scrapie in endemically affected sheep flocks.