Table 1.

Some examples of melatonin content in plants and foods measured by immunological and chromatographic techniques

Plant/food	Melatonin	Reference
Tomato	3–114 ng/g	32, 37
Walnuts	3–4 ng/g	30
Cereals (rice, barley)	300–1,000 pg/g	39
Strawberry	1–11 ng/g	32
Olive oil	53–119 pg/ml	34
Wine	50–230 pg/ml	32, 36
Beer	52–170 pg/ml	43
Cow's milk (unprocessed)	3–25 pg/ml	38, 40
Nighttime milk	10–40 ng/ml	62