How to Reduce Harmful Byproducts when Cooking Pasta with Iodized Salt

In many countries, drinking water is treated with chlorine or chloramine for disinfection. Small amounts of residues of these disinfectants can end up in water used for cooking. These residues can react with dissolved organic matter and/or halide ions to form disinfection byproducts (DBPs). These byproducts can be potentially harmful to human health. Iodized table salt, for example, could lead to iodinated DBPs (I-DBPs). Bromides can also co-occur in table salts.

Susan D. Richardson, University of South Carolina, Columbia, USA, and colleagues have investigated I-DBP formation upon cooking pasta with water containing iodized table salt, as well as tried to find possible control measures to reduce I-DBP formation. The team selected the iodinated trihalomethanes dichloroiodomethane (DCIM), dibromoiodomethane (DBIM), bromochloroiodomethane (BCIM), chlorodiiodomethane (CDIM), bromodiiodomethane (BDIM), and triiodomethane (TIM), as well as iodoacetonitrile (IAN) as target I-DBPs. Since food samples can be a complicated matrix for analysis, the researchers developed an optimized method for sensitive measurements that involves sample cleanup with a sorbent, extraction, calibration, and analysis using gas chromatography–mass spectrometry (GC–MS).

The researchers cooked pasta in chloraminated tap water with iodized table salt and assessed the DBP formation in the pasta and the boiling water. They also varied the cooking conditions and salt type. They detected all of the target I-DBPs in the pasta and pasta water when iodized table salt was used, but the cooking conditions significantly impacted the amounts. Based on their results, the researchers identified four ways to reduce the consumption of these substances: 1) Pasta can be boiled without a lid; 2) it should be strained from the water; 3) iodized table salt could be added after the pasta is cooked; 4) iodine-free salt options could be used if pasta is boiled in salted water.