Introduction
Integrated Multitrophic Aquaculture (IMTA) has been suggested as an innovative method of aquaculture development (Mansour et al, 2022) that ensures sustainable development in agreement with the EU directions for Blue Growth and Blue Economy. Methodology of co-culture fishes, bivalves and holothurians have been developed in Mediterranean waters (Chatzivasileiou et al 2022). Although, studies on IMTA project have promising results in Mediterranean waters (Chatzivasileou et al 2022), food safety of IMTA organisms has not been studied extensively. According to the Greek and European law it is not yet allowed to cultivate and commercialize organisms cultured in IMTA systems due to lack of specific IMTA food safety protocols. In the context of Innovated Development of Marine Aquaculture (IDMA) project after the co-cultivation of fishes, bivalves and holothurians, an investigation of food safety parameters was implemented. The results are expected to facilitate the European Food Safety Authority and the Greek Food Authority to compose safety protocols for IMTA products and consequently to permit the development of commercial IMTA systems.
Material and Methods
In this study, three Mediterranean species were co-cultured in three operating fish farms in the Aegean with different trophic conditions. It is defined as the cultivation of two or more aquatic species from different trophic levels in the same area in order to mimic the energy flow in natural ecosystems (Chapin T. et al 2004) The co-cultivated species were Mediterranean mussel (Mytilus galloprovincialis), rayed pearl oyster (Pinctada imbricata radiata), and sea cucumber (Holothuria polii) as described by Chatzivasileiou et al (2022). After a year of cultivation, edible tissue samples were collected for the co-culture species, in order to find out if the co-cultivated organisms are appropriate for consumption. The food safety analysis included the determination of antibiotics (oxytetracycline, florfenicol), metals (Hg, Pb), dioxins and related substances (PCBs, PCDDs, PCDFs, PBDEs, DDT, DDE, HCB, PFAs, and lastly biotoxins (DSP, PSP, ASP). All the analysis was conducted in samples of IMTA cultured sea cucumber, mussels and oysters as well as samples for a typical mussel farm and oyster and sea cucumber natural population.
Results
European committee has established limits on oxytetracycline and florfenicol concentrations for safe consumption of food products (100μg/kg for mussels and oysters, Regulation EU 37/2010). Our results showed that the concentrations of the two antibiotics were under the permitted limits for all samples regardless the type of mussel cultivation. Metals concentrations in this study were below the food safety limits defined by the European committee (0.5 mg/kg WW for Hg, and 1 mg/kg WW for Pb, Regulation EU 4661/2001). The permitted limits of dioxins and dioxins like substances is 3.5 pg/g for TEQ PCDD/PCDF, 6.5 pg/g TEQ PCBs, 75 ng/g for PCBs, 50 mg/kg for DDT, for HCB and for PBDEs (Regulation EU 1259/2011 and 2019/1021). In this study, the concentrations of organic pollutants were below the safety limits for IMTA mussels and oysters. Lastly, the permitted limits of marine biotoxins DSP, PSP and ASP are 160 mg/kg, 800 mg/kg and 200 mg/kg respectively (Regulation EU 853/2004). Our results showed that the biotoxins concentrations were very low and under the safety limits for all mussels and oysters’ samples.
Conclusions
Until now the products of an IMTA aquaculture couldn’t commercialize, cause the lack of knowledge regarding the safe consumption of the IMTA organism. These results showed that bivalves and holothurians cultivated in a fish farm area are safe for human consumption, and IMTA aquaculture is a safe method to co-cultivate species from different trophic levels. Aquaculture wastes were not contaminating the co-culture species with antibiotics, toxins or metals. That fact makes IMTA aquaculture a promising method to cultivate more species in the same farm
Bibliography
Chatzivasileiou D., P.D Dimitriou, J. Theodorou, I. Kalantzi, I. Magiopoulos, N. Papageorgiou, P. Pitta, M. Tsapakis and I. Karakassis. “An IMTA inGreece: Co-Culture of Fish, Bivalves, and Holothurians” https://doi.org/10.3390/jmse10060776. 2022.
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Mansour A. T., M. Ashour, A. E. Alprol, and A. S. Alsaqufi, “Aquatic Plants and Aquatic Animals in the Context of Sus-tainability : Cultivation Techniques , Integration , and Blue Revolution,” 2022.