Microbiological analysis of peanuts samples from Porto Alegre/RS public market.

Abstract

Peanuts are a widely consumed legume, despite the risk of contamination by fungi and bacteria being large. The objective of this study was to evaluate the presence of total coliforms, thermotolerant coliforms, aerobic mesophilic bacteria, molds and yeasts, samples of roasted peanuts sold in the public market of Porto Alegre/RS stocked in three different ways. The results indicated absence of fungi or yeasts, but aerobic mesophilic bacteria were found in all types of storage, and in the gravitational dispenser (1V) the count was 3,7 x 102UFC/g, followed by the bulk bin (2-G) with 3,6 x 102UFC/g and in smaller quantity, the industrialized (1I) with 2,7 x 102UFC/g. Total coliforms were found in the same samples, 1V (2,4 x 102NMP/g), 2-G (1,3 x 102NMP/g) and 1I (1,1 x 101NMP/g). Eighteen bacteria, mostly Gram positive, were identified from 16SrRNA gene sequencing. Pathogenic bacteria of importance in foods found in the analyzed peanut sampleswere Bacillus cereus, Pseudomonas aeruginosa and Staphylococcus sp., and this contamination of may come from non-compliance with good practices in handling and lack of asepsis in storage.