Microbial diversity in pitted sweet cherries (Prunus avium L.) as affected by High-Hydrostatic Pressure treatment

Food Research International Volume 89, 1 November 2016, Pages 790-796 Microbial diversity in pitted sweet cherries (Prunus avium L.) as affected by High-Hydrostatic Pressure treatment (Article) Toledo del Árbol, J.ab, Pérez Pulido, R.a, La Storia, A.b, Grande Burgos, M.J.a, Lucas, R.a, Ercolini, D.b, Gálvez, A.a a Área de Microbiología, Departamento de Ciencias de la Salud, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain b Department of Agricultural Sciences, Division of Microbiology, University of Naples Federico II, Via Università 100, Portici, Italy View references (42) Abstract Sweet cherries are a highly appreciated seasonal fruit rich in anthocyanins. The purpose of the present study was to determine the effect of High-Hydrostatic Pressure (HHP) processing on the microbiological quality and bacterial biodiversity of sweet cherries. Pitted cherries inoculated with their own epiphyte microbiota to simulate a worst-case scenario of contamination during preparation and processing were treated or not by HHP (600 MPa, 8 min) and stored at 4 °C for 60 days. HHP treatment reduced total viable counts by 4.65 log cycles. The surviving bacterial fraction did not increase significantly (p < 0.05) for the first 15 days of storage. Concentrations of yeasts and molds were reduced below detectable levels. Upon prolonged storage (60 days), microbial growth was observed. Bacterial biodiversity studied by high-throughput sequencing of the 16S rRNA gene revealed that Proteobacteria had highest relative abundance (88.70%) in the spiked cherries followed by Firmicutes (11.04%). Gluconobacter and Enterobacteriaceae together with Leuconostoc were the most abundant Operational Taxonomic Units (OTUs). Upon application of HHP treatment, 97.62% of OTUs from the surviving fraction belonged to Proteobacteria. The relative abundance of Enterobacteriaceae also decreased markedly while Acetobacteraceae (represented mainly by Gluconobacter) increased to 89.18%. Gluconobacter dominated during storage. Results from the present study provide insights on the microbiota of sweet cherries and the dynamics of the bacterial populations surviving HHP treatments that may be useful to improve the non-thermal preservation of cherries.