Comprehensive strategy for pesticide residue analysis through the production cycle of gilthead sea bream and Atlantic salmon

Abstract

Plant ingredients and processed animal proteins are alternative feedstuffs for fish feeds in aquaculture. However, their use can introduce contaminants like pesticides that are not previously associated with marine Atlantic salmon and gilthead sea bream farming. This study covers the screening of around 800 pesticides by gas chromatography (GC) and liquid chromatography (LC) coupled to high resolution time-of-flight mass spectrometry in matrices throughout the entire marine food production chain. Prior to analysis of real-world samples, the screening methodology was validated for 252 pesticides to establish the screening detection limit. This was 0.01 mg kg for 113 pesticides (45%), 0.05 mg kg for 73 pesticides (29%) and >0.05 mg kg for 66 pesticides (26%). After that, a quantitative methodology based on GC coupled to tandem mass spectrometry with atmospheric pressure chemical ionization source (GC-APCI-MS/MS) was optimized for the pesticides found in the screening. Although several polar pesticides, of which pirimiphos methyl and chlorpyriphos-methyl were most dominant, were found in plant material and feeds based on these ingredients, none of them were observed in fillets of Atlantic salmon and gilthead sea bream fed on these feeds.

Comprehensive overview of feed‐to‐fillet transfer of new and traditional contaminants in Atlantic salmon and gilthead sea bream fed plant‐based diets

“…Around 10 years ago, the starting point was the use of target methods mainly focused on a reduced list of contaminants, including POPs, associated with marine ingredients (Berntssen et al., ; Saera‐Vila et al., ). To be coherent with current feed compositions, and to deal with potential contaminants introduced by new alternative plant sources, advanced analytical methodologies have been developed and validated (Nácher‐Mestre et al., , , ; Portolés, Ibáñez, et al., ; Portolés, Garlito, et al., ). These methodologies also cover traditional contaminants from marine ingredients, and therefore include detection, reliable identification and quantification of POPs, PBDEs, pesticides, PAHs and mycotoxins, as the main groups of analytes, using hyphenated techniques such as GC‐MS/MS and LC‐MS/MS, as well as GC and LC coupled to HRMS (Berntssen, Maage, Julshamn, Oeye, & Lundebye, ; Berntssen et al., ; Berntssen, Julshamn, et al., ; Berntssen, Olsvik, et al., ; Nácher‐Mestre, Serrano, Benedito‐Palos et al., ; Nácher‐Mestre, Serrano, Portolés, et al., ; Nácher‐Mestre, Serrano, Hernández, et al., ; Nácher‐Mestre et al., , , ; Portolés, Ibáñez, et al., ; Portolés, Garlito, et al., ; Regueiro et al., ).…”

“…Organophosphorus pesticides, such as chlorpyrifos‐methyl and pirimiphos‐methyl, and others, such as boscalid and azoxystrobin, were found in both Atlantic salmon and gilthead sea bream feeds, at concentrations below 50 μg/kg (Tables ). However, it is important to note that these pesticides were not detected in fish fillets (Portolés, Ibáñez, et al., ; Portolés, Garlito, et al., ). Under the conditions of the experimental feeding trials, it appears that the studied pesticides do not represent a food safety concern at commercial sizes but can potentially represent a fish welfare issue (Sanden et al., ).…”

“…This fact had been already confirmed for the case of salmon, a so‐called “oily” fish with higher feed intake rates and bioaccumulation higher than other Mediterranean species like gilthead sea bream (Berntssen et al., ; Nácher‐Mestre, Serrano, Portolés, et al., ; Nácher‐Mestre, Serrano, Hernández, et al., ). As no PCBs, DDTs or HCB were found in fillets, no transfer factors could be calculated (Nácher‐Mestre et al., ; Portolés, Ibáñez, et al., ; Portolés, Garlito, et al., ). It is important to remark that the high inclusion of plant ingredients in novel feeds with marine ingredient concentrations lower than 150g/kg in the case of salmon, and lower than 80g/kg for gilthead sea bream, contributed to the nondetection of nonpolar/persistent contaminants in the edible fillets of salmon and sea bream.…”

“…In particular, AQUAMAX (2006–2010) and ARRAINA (2012–2016) EU projects have highly contributed on this, providing valuable samples but also adequate analytical methods and approaches to assess the presence of potential contaminant residues in the aquaculture food chain (Justino et al., ; Nácher‐Mestre, Ibáñez, Serrano, Pérez‐Sánchez, & Hernández, ; Nácher‐Mestre, Serrano, Hernández, Benedito‐Palos, & Pérez‐Sánchez, ; Nácher‐Mestre, Serrano, Benedito‐Palos, et al., ; Nácher‐Mestre, Serrano, Portolés, et al., ; Nácher‐Mestre, Serrano, Benedito‐Palos, et al., ; Nácher‐Mestre et al., , ; Portolés, Garlito, Nácher‐Mestre, Berntssen, & Pérez‐Sánchez, ; Portolés, Ibáñez, et al., ; Regueiro, Negreira, & Berntssen, ). Advanced analytical methodologies based on the use of both gas chromatography (GC) and liquid chromatography (LC) coupled with low‐ and high‐resolution mass spectrometry (MS and HRMS, respectively) make feasible to analyse large lists of organic compounds (Portolés, Ibáñez, et al., ; Regueiro et al., ). Traditional target methods are usually focused on a reduced list of organic compounds, generally with quantitative purposes and using tandem MS techniques (Nácher‐Mestre, Serrano, Portolés, et al., ; Nácher‐Mestre, Serrano, Hernández, et al., ; Saera‐Vila et al., ; Serrano, Barreda, Pitarch, & Hernández, ).…”

“…Besides, these specific contaminants, other nontarget (non‐pre‐selected) unknown and/or nonexpected undesirables, can potentially contribute to food safety of farmed fish. This is an analytical challenge that requires, among others, the application of wide‐scope analytical methodologies able to detect and identify a large number of very different potential undesirables in the aquaculture food chain as reported elsewhere (Hernández et al., ; Justino et al., ; Nácher‐Mestre et al., , , ; Portolés, Ibáñez, et al., ; Regueiro et al., ).…”