Zhao et al. 2021 — Cadmium Removal from Rice Flour by Coimmobilized Microorganisms
This 2021 laboratory study evaluated bioremediation of cadmium from rice flour using Lactobacillus plantarum coimmobilized with other microorganisms. The study reports both baseline Cd in the rice flour samples and post-treatment removal efficiency.
Key numbers
Baseline Cd in rice flour samples (mg/kg):
| Sample | Cd (mg/kg) | Cd (µg/kg equivalence) |
|---|---|---|
| Sample 1 (after treatment reference) | 0.051 ± 0.003 | 51 ± 3 |
| Sample 2 (after treatment reference) | 0.068 ± 0.034 | 68 ± 34 |
Note: These are post-treatment values; pre-treatment Cd was approximately 10× higher given the reported removal efficiencies. Implied pre-treatment values: sample 1 ~510 µg/kg, sample 2 ~830 µg/kg. These pre-treatment values suggest the rice flour was sourced from a contaminated batch.
Removal efficiency: 90.01 ± 1.01% (sample 1), 91.80 ± 0.54% (sample 2).
Methods
Coimmobilized Lactobacillus plantarum biosorption. Laboratory scale. Wet weight basis. n=2 samples. The pre-treatment Cd concentrations implied by the removal efficiencies (500–830 µg/kg) are well above EU MLs for rice flour (Cd ML for cereals: 100 µg/kg, Codex; EU Regulation 2023/915: 400 µg/kg for rice). This paper is primarily a processing/mitigation study, not a concentration survey.
Implications
Mitigation: Demonstrates microbial biosorption as a viable in-vitro Cd reduction approach; ~90% efficiency is notable though industrial scalability is unproven.
Certification: The implied pre-treatment Cd levels (~500–830 µg/kg) represent a contaminated batch scenario, not representative of the commercial rice flour supply chain. Do not use post-treatment values as baseline estimates.