Effect of ozone on Enterobacteriacea spp. in seeds of alfalfa, wheat grain and sprouts

Seeds and grains are not only a basic component of the agricultural system, but also an integral part of the food basket. Cereal products alone account for half of the world’s food consumption. The sprouts of various seeds have gained a lot of attention among consumers due to freshness, crispness and germination, as a cheap and simple process. Warm and moist germination conditions are ideal for the growth of microorganisms. This raises food safety concerns. The aim of this study was to determine the effect of ozone on Enterobacteriacea spp. by treating alfalfa (Medicago sativa) seeds and wheat (Triticum aestivum) grain with ozone gas and rinsing with ozonated water during germination. VRBG (Violet Red Bile Glucose Agar) medium was used to detect Enterobacteriacea spp. Dry seeds and wheat grain were treated with ozone gas at 20 ppm for 10 minutes, and during germination, seeds and grains every 12 hours were rinsed with ozonated water in a flow-through, where the concentration of ozone in the water was 2.0 mg LE−1. Rinsing with ozonated water was performed for 20, 40, 60 minutes. Untreated alfalfa seeds and wheat grain were used as controls. When evaluating samples of alfalfa seeds, Enterobacteriacea spp. was not detected in dry seeds and in the washing water of untreated seeds, but in the washing water of seeds planted with ozone gas, 2.6 log CFU gE−1 was found. After 12 hours of soaking, it increased to 5.5 log CFU gE−1. After 24 hours of germination and rinsing with ozonated water, as well as after 7 days of storage at 4 ± 2 °C, Enterobacteriacea spp. was detected in all samples at an average of 8.0 log CFU gE−1, regardless of the duration of rinsing. When evaluating the wheat grain samples, Enterobacteriacea spp. was already detected in dry grains on average up to 0.5 log CFU gE−1, gradually increasing to 5.5 log CFU gE−1 in soaked grains, after 24 hours of germination it already reached 7.5 log CFU gE−1 in both control and ozone-treated samples, but after 7 days of storage, 6.5 log CFU gE−1 was found.