Fate of Salmonella Enterica in Sprouted Peanut and Almond Butter Affected by the Use of Ellagitannins From Aqueous and Ethanolic Extracts of Pomegranate Peels.

A trend of consuming sprouted nut butter is emerging due to its nutrient values. However, sprouted nuts have been involved in several enteric disease outbreaks. This study evaluated the inhibitory effect of an aqueous and ethanolic extract of a pomegranate peel against strains of Salmonella Tennessee and Enteritidis in sprouted nut butter. Raw, organic peanut and almond seeds inoculated with one of the Salmonella strains (1.16-1.97 log CFU/g) were sprouted in deionized water containing 10% of the aqueous or ethanolic extract for 24 h at 25°C. Sprouted nuts were rinsed with sterile deionized water and dried at 45°C for 12 h. Dried nuts were then ground with olive oil and sea salt. Salmonella population was determined after each preparation step. Data fit into the general linear model were analyzed using ANOVA. Fisher's LSD test was used to separate the means (α ≤ 0.05). The peanut samples treated with either ethanolic or aqueous extract had significantly (P ≤ 0.05) lower Salmonella Tennessee populations compared to the controls after sprouting (1.8-2.2 log CFU/g) and rinsing (1.4-1.6 log CFU/g). After drying and seasoning, significant differences in the populations of both Salmonella strains compared to their controls were only observed in sprouted peanut and almond seeds/butter containing ethanolic extract, with reductions reaching up to 3.2 log CFU/g. However, the extract could not eliminate Salmonella from sprouted nut butter. During the 3-week storage, Salmonella populations changed by < 1 log CFU/g across strains and extracts. Thus, additional antimicrobial intervention is needed. PRACTICAL APPLICATIONS: Despite the nutritional values, sprouted nut butter could potentially pose a food safety risk to consumers. The product may have the potential to harbor a higher number of bacterial cells than the initial contamination level on the nut stock. The addition of pomegranate ethanolic extract in nut sprouting water could significantly lower bacterial population, but the use of this natural antimicrobial, plus drying sprouted nuts at 45°C and seasoning the nut homogenates with olive oil and salt, is inadequate in eliminating bacterial cells, as evidenced by the relatively high bacterial populations in nut butter products.