<p>Contamination of food with heavy metal ions and nitrites poses a serious threat to human health. Consequently, the development of fast and sensitive platforms for detecting these contaminants is urgently required. In this paper, a novel MnMgFe-LDHs/DC sensor is constructed based on a simple strategy, in which MnMgFe layered double hydroxide (LDHs) is used as a metal precursor, and a unique "island bridge" carbon network structure is generated by its pyrolysis with ZIF-8@B, N-WMCNTs. The electrical conductivity was enhanced, and a large electroactive surface area was provided for the MnMgFe-LDHs/DC. The electrochemical properties of Pb²⁺, Cd²⁺ and nitrite were investigated using this electrode as a working electrode. Under optimized conditions, the sensing platform exhibited a wide linear range with the Pb²⁺, Cd²⁺, and NO₂⁻ limits of detection of 46.16&#xa0;nM, 59.25&#xa0;nM, and 0.083&#xa0;μM, respectively. Of particular note is that this sensing platform exhibits outstanding anti-interference capabilities. It can precisely and efficiently conduct the detection of nitrite and heavy metal ions in pickled foods.</p>