Goh, Ngee Chuang (2023) Effects Of Cooking Methods In Reducing Risk To Essential And Toxic Metals Exposure In Rice (Oryza Sativa) – Health Risk Assessment In Malaysia. Masters thesis, Universiti Sains Malaysia.
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Abstract
The ubiquity of metal contamination in rice grains has been well documented worldwide. Malaysia is no exception, as reports of metal contamination in rice grains collected from various states have surfaced recently. Many studies have investigated cooking treatments to reduce the metal contamination in rice which efficacy were still unexplored on Malaysian sourced rice. The aim of this research was to investigate the effectiveness of cooking treatments, absorption cooking and parboiling before absorption cooking (PBA) on rice samples bought from Malaysian supermarkets. Metal quantification was conducted via tandem inductively coupled plasma mass spectrometry (ICP-MS/MS) and further health risk assessment (HRA) was conducted according to the USEPA framework for metal risk assessment. The findings indicated that PBA successfully eliminated 77.9% of toxic metals (Al, As, Cd, Cr, Ni, and Pb), while removing 68.4% of essential metals (Co, Cu, Fe, Mg, Mn, Zn). Importantly, this method ensured that concentrations of As, Cd, and Pb in all samples remained below the permissible limits according to the Malaysian Food Regulations 1985. The effectiveness of PBA can be attributed to the disposal of boiled excess water which contained dissolved metals from the rice before the rice was fully cooked. Deterministic health risk assessment (HRA) revealed that PBA significantly reduced the Hazard Index (HI) by 84.5% and Lifetime Carcinogenic Risk (LCR) associated with As exposure by 88.9% compared to controls. PBA effectively reduced the non-carcinogenic health risks posed by Cd, Mn, Ni, and Zn below the acceptable limit (Hazard Quotient (HQ) = 1) for all age groups, except As in children. However, LCR remained above the upper permissible limit (1 x 10-4) for all age groups. Probability-based HRA using Monte Carlo simulations indicated that the majority (>95%) of children, adolescents and adults would experience unacceptable total non-carcinogenic and carcinogenic health risks from As exposure, regardless of the cooking method employed. These results indicate that the PBA method was effective in reducing both concentration of metal as well as health risk posed by toxic metals in rice.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | R Medicine > R Medicine (General) |
| Divisions: | Institut Perubatan & Pergigian Termaju (Advanced Medical & Dental Institute (AMDI)) > Thesis |
| Depositing User: | MUHAMAD AMIN BIN AZMI |
| Date Deposited: | 13 Jul 2026 01:44 |
| Last Modified: | 13 Jul 2026 01:44 |
| URI: | http://eprints.usm.my/id/eprint/64614 |
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