Calcium chloride toxicology for food safety assessment using zebrafish (Danio rerio) embryos

The salt calcium chloride (CaCl2) is widely used in industry as a food additive; levels for human consumption are regulated by international or governmental agencies. Generally, the food industry relies on toxicity studies conducted in mammals such as mice, rats, and rabbits for determining food safety. However, testing in mammals is time-consuming and expensive. Zebrafish have been used in a range of toxicological analyses and offer advantages with regard to sensitivity, time, and cost. However, information in not available with regard to whether the sensitivity of zebrafish to CaCl2 is comparable to the concentrations of CaCl2 used as food additives. The aim of this study was to compare the CaCl2 tolerance of zebrafish embryos and larvae with concentrations currently approved as food additives. Acute toxicity, embryotoxicity, cardiotoxicity, and neurotoxicity assays were used to determine the threshold toxic concentration of CaCl2 in zebrafish embryos and larvae. The data showed that doses above 0.4% had toxic effects on development and on the activity of the cardiac and neuronal systems. Furthermore, all embryos exposed to 0.8 and 1.6% of CaCl2 died after 24 hpf. These findings are consistent with the limits of CaCl2 concentrations approved by Codex Alimentarius. Therefore, zebrafish embryos could be suitable for screening food additives