Microbiological Quality of Peanuts: From Field to Consumption

Abstract

Peanuts, including shelled peanuts, unshelled peanuts and roasted peanuts which are ready to eat foods, recently appeared as possible sources of infection with foodborne bacteria besides the high levels of aflatoxins. Peanuts which are taken from harvest, storage and snack shops were evaluated for the presence of Listeria spp. and Salmonella spp; also total aerobic mesophilic bacteria, coliforms, E.coli. and yeasts and moulds, were enumerated.A total of 92 samples were found to be clean in terms of Salmonella and E-coli O157: H7, but only in 1 of the samples of shelled peanut taken from harvest found Listeria spp. Shelled peanut samples collected from harvest and storage were found to be contaminated in terms of microorganisms, however, microbiological contamination was found to be less in the samples obtained when the shells of the same specimens were removed.In addition, in terms of microorganisms it was observed that the shell free samples taken from storage were dirtier than the samples which was being removed the shell taken from storage. Shell-free (unpackaged) roasted peanuts samples purchased from the snack shops was found clean in terms of the pathogens. When salt and heat treatment applied over 4%, existing microorganisms can be damaged. Besides, the water activity value of the product can reduce the level of that microorganisms growth. Therefore, processed peanuts are safer in the environment in which they are stored, unless the relative humidity increase and is not subject to cross-contamination.