Are the salt-like crystals on spinach safe to eat?

　　The salt-like crystals appearing on spinach may be edible if they are natural oxalate crystals, but inedible if caused by pesticide residues, pollutants, or decomposition products. Judgments should be made by observing their appearance and using proper washing methods to avoid accidentally consuming harmful substances.

　　Spinach naturally contains a relatively high amount of oxalic acid. During storage, as moisture is lost, the concentration of oxalic acid increases, potentially forming white needle-like or granular crystals. These are natural compounds and not harmful; most of the oxalic acid can be removed by rinsing and blanching in boiling water before consumption.

　　However, if the crystals on the spinach surface appear irregular, dark-colored, or are accompanied by an unusual odor, they may stem from pesticide residues, environmental contaminants, or harmful substances produced during spoilage. Consuming such crystals could irritate the gastrointestinal tract and potentially cause discomfort.

　　When preparing spinach, first rinse it thoroughly under running water, then blanch in boiling water for 1–2 minutes. This process effectively removes natural oxalate crystals and reduces potential chemical residues. For storage, keep spinach in a cool, moist environment to prevent excessive dehydration and minimize crystal formation.