Due to their high nutritional value and functional content, barley sprouts are commonly ground into powder for human use. This study investigated the effect of drying methods, viz., hot-air drying (HAD), freeze-drying (FD), and infrared drying (IRD), and storage conditions for the removal of Escherichia coli quality parameters of barley sprouts. Herein, the barley sprouts were subjected to HAD, FD, and IRD and stored at different temperatures, such as −20, 4, and 25°C, for six months. The changes in the colony count of E. coli and food quality indicators, viz., Hunter color, chlorophyll, and saponarin, were measured once a month. The HAD and FD were found to reduce E. coli from 7 log CFU/g to 4 log CFU/g, whereas IRD eliminated them (limit of detection ⟨ 1 log CFU/g). In the case of HAD, the E. coli counts and the quality of dried leaves did not change significantly (p>0.05) for six months under all storage conditions. Freeze-dried leaves stored at 25 and 4°C showed a decrease in E. coli counts from 4.5 to 1.2-1.5 log CFU/g after six months (p⟨0.05), and no significant change in quality during their storage was observed (p⟩0.05). In the case of infrared-dried samples, E. coli was not detected even after six months under all storage conditions, storing at −20°C was the best condition for the chlorophyll content and Hunter color (p⟨0.05). On the other hand, the content of saponarin was constant regardless of the drying method and storage.

Fresh food products can be contaminated with pathogenic bacteria in various agricultural environments. Potting soil is sterilized by heat sterilization and then reused. This study evaluated the effects of three sterilization methods (non-sterilized, pasteurized, and sterilized) on the survival of pathogenic bacteria in potting soil during storage for 60 days at 5, 15, 25, and 35 °C. The reduction in Escherichia coli O157:H7, Salmonella Typhimurium, and Staphylococcus aureus in potting soil was higher at higher temperatures (25 and 35 °C) than at lower temperatures (5 and 15 °C). The population of pathogenic bacteria in pasteurized and sterilized potting soil was reduced below the detectable levels within 30 days at 35 °C. In contrast, the population of Bacillus cereus did not change in potting soil during storage for 60 days at all temperatures. These results indicate that sterilization and storage temperature of potting soil are critical factors influencing the survival of pathogenic bacteria.

Contamination by Listeria monocytogenes in packaged produce is a major concern. The purpose of this study was to find natural and affordable sanitizers to reduce L. monocytogenes contamination in agricultural products. Organic acids, ultraviolet-C (UV-C), and ethanol were analyzed either alone or in combination to assess their ability to reduce L. monocytogenes population in radish, oriental melon, and carrot samples. In radish samples, 3% malic acid combined with UV-C at a dosage of 144 mj/cm² significantly reduced (>4 log CFU/g) the population of L. monocytogenes (1.44 ± 0.5) compared to the control sample (5.14 ± 0.09). In the case of the melon samples, exposure to UV-C at a dosage of 144 mj/cm² combined with 3% lactic acid (2.73 ± 0.75) or 50% ethanol (2.30 ± 0.01) was effective against L. monocytogenes compared to the control sample (5.10 ± 0.19). In carrot samples, 3% lactic acid combined with 144 mj/cm² dosage UV-C reduced L. monocytogenes population (4.48 ± 0.25) more than in the control sample (5.85 ± 0.08). These results reveal that sanitizers that are effective for one crop are less effective for another crop indicating that effective prevention methods should be customized for each crop to prevent pathogen cross contamination during postharvest washing.

Recently, consumers demand for healthy and fresh foods, including fresh ginseng and ginseng sprouts has increased. However, evaluation of microbial safety for ginseng sprouts have not been intensively conducted. The purpose of this study was to investigate microbial contamination levels on ginseng sprouts produced on 20 different farms and green moss used as packaging material at these farms. Microbial contamination levels of sanitary indicator microorganisms (total aerobic bacteria, Escherichia coli, coliform, yeasts, and molds) and foodborne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus) were evaluated in ginseng sprouts and green moss. As a result, the abundance of total aerobic bacteria in ginseng sprouts and green moss ranged from 5.52-8.08 and 5.74-9.70 log CFU/g, respectively. The average population of yeasts and molds on ginseng sprouts and green moss were observed to be > 3 log CFU/g at all the farms. In particular, the average populations of B. cereus in ginseng sprouts and green moss were 3.56 and 5.88 log CFU/g, respectively. Foodborne pathogens were not detected in all ginseng sprouts. However, Staphylococcus aureus was detected in 7 (41%) out of 17 green moss. Therefore, the study findings highlight the need of developing an effective control strategy for eliminating hazardous microorganisms, to improve the microbial safety of ginseng sprouts.

Jeong-Eun Hyun, Su-Bin Lee, Do-Young Jung, Hyo-Bin Chae, Song-Yi Choi, Injun Hwang, and Se-Ri Kim. Journal of the Korean Society of Food Science and Nutrition 2023;52:307-14. https://doi.org/10.3746/jkfn.2023.52.3.307