Microbial Safety of Black Summer Truffle Collected from Sicily and Umbria Regions, Italy

Abstract

Background: Tuber aestivum Vittad., known as black summer truffle, represents high-value food especially used as garnishment in nouvelle cuisine. The aim of this study was to investigate on the viable microbial populations associated with T. aestivum ascomata collected in different sites of Sicily and one locality of Umbria (Italy).
 Methods: The ripe ascomata of black summer truffles were collected from Central Italy. Cell densities of spoilage bacteria, fecal indicators, potential pathogens, yeasts, and molds were analyzed. Statistical analysis was conducted with XLSTAT software.
 Results: The microbiological counts of truffles ranged between 6.00 and 9.63 log Colony Forming Unit (CFU)/g for total mesophilic count and between 6.18 and 8.55 log CFU/g for total psychrotrophic count; pseudomonads were in the range 6.98-9.28 log CFU/g. Listeria spp. and coagulase-positive streptococci detected in no samples. Coagulase-negative streptococci were found in some samples with 2.11-4.76 log CFU/g levels. Yeasts and filamentous fungi were detected at consistent levels of 3.60-7.81 log CFU/g. Significant differences (p<0.01) were found between samples and also for all microbial groups.
 Conclusion: This study evidenced that the common brushing procedure applied for preparation of truffles is not sufficient to eliminate microbial risks for consumers. The application of an efficient decontamination treatment is strongly suggested before consumption of fresh truffles.

Assessment of Microbiological Properties, Mycotoxins, and Heavy Metals in Underprized Raw Kalahari Truffles Sold in Namibia

“…The total coliforms results were similar to those reported by Cirlincione et al (2021) on black summer truffles in Italy. The unwashed truffle (T 1 , T 2 , T 3 , and T 8 ) and the washed T 4 samples had higher total coliform counts than the total coliforms counts (4.0 log CFU/g) that Reale et al (2009) detected on fresh black truffles in Italy.…”

“…The yeast counts were in the same range as those reported by Cirlincione et al (2021) on black summer truffles in Italy. They were also similar or higher than the 4-5.5 log CFU/g reported in truffles from Spain by Phong et al (2022) and were higher than the 3.4 log CFU/g yeast counts that Rivera et al (2010) detected in dried Tuber aestivum and Tuber melanosporum truffles samples that were also from Spain.…”

“…However, the mould counts between unwashed and washed truffles did not generally differ significantly. For most of the samples irrespective of washing, mould counts were similar or higher than the values reported by Cirlincione et al (2021) on black summer truffles in Italy and by Tejedor-Calvo et al (2020) on fresh truffles in Spain. Furthermore, the mould values in this study were higher than the 3.7 log CFU/g that Rivera et al (2011) detected in fresh T. aestivum truffles from Spain.…”