Novel Non-Thermal Treatments in Postharvest Processing of Food and Feed Commodities.
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Protecting our food and feed supply from postharvest losses will be key to increasing the availability of food and feed come 2050. Postharvest handling and storage are major components of the 1.3 billion tons of food wasted or lost each year. During storage, there is the risk of increased microbial contamination and mycotoxin development in food and feed commodities, which can lead to issues with human, animal, and plant health (Crump et al., 2002, D'mello et al., 2004, Gourama et al., 1995, Obuseh, et al., 2011, Placinta et al., 1998). These spoilage organisms have an impact on the quality and shelf life. Losses that occur during postharvest have negative externalities such as increase in waste management cost and greenhouse gas production.Aflatoxins are toxic mycotoxin produced by the common stored grain fungi, Aspergillus flavus. Aflatoxin (B1) is categorized as a class I carcinogen by the World Health Organization and when present impact food and feed quality. People worldwide are at risk to chronic aflatoxin exposure which causes liver cancer, impaired immune function, childhood stunting, and possible neural tube defects. Likewise, the amount of aflatoxin content has a direct impact on livestock through acute toxicity, reduced growth rates and weight, and immunosuppression at low doses. The spoilage that occurs during storage of high moisture commodities such as corn, cottonseed meal, and peanuts can result from the aforementioned microbial and mycotoxin exposure as well as intentional contamination. There is a need to set up control and treatment methods for postharvest protection to reduce the instances of such mycotoxins and provide high quality and safe commodities.Using solvent or chemical processes to treat food and feed commodities postharvest may lead to changes with the composition. Also, heat treatments alone do not always effectively eliminate aflatoxins from contaminated products. Novel non-thermal treatment technologies such as ozone and atmospheric cold plasma (ACP) continue to be effective in quickly reducing microbial infestations and mycotoxin levels in stored grains. Ozone is a desired sanitizer for sterilizing surfaces and preventing microbial activity in treatment, storage, and the processing of foods. Similar to ozone, ACP consists of various reactive gas species and is successful at inactivating different pathogens. Ozone from plasmas are created by discharging electrical energy into a dielectric medium causing ionization, dissociation and energizing of the gas molecules (Grabowski, 2007). Klockow et al. (2009) used the O3 generation system, also referred to as the ionization system, to reduce Escherichia coli O157:H7 populations on packaged spinach. There have been early studies of gaseous ozone to prevent microbial activity on food surfaces and extend the shelf life of grains, fruits and vegetables, including research by this author and her collogues (McClurkin, 2009; McClurkin-Moore et al., 2017; Hu et al., 2017). The usage of such novel non-thermal treatment technologies, ACP and ozone, are methods to protect our food and feed supply from compounds which lead to reduced quality and post-harvest loss.