Research on mesophilic aerobic microorganisms and Enterobacteriaceae in cultivated and commercialized Agaricus bisporus.

BACKGROUND: Production and consumption of fresh mushrooms reached high levels in recent years but only a few data regarding microbiological quality of these products are available, although their potential microbial load is expected to be high. EU and Italian legislation have not set a limit on microbial counts in these products and label information is often unclear. This study investigates the microbial quality of samples of fresh cultivated mushrooms sold in Tuscany so that both food business operators and legislators can obtain data about potential microbial risk for consumers and debate about the opportunity of realizing an update on fresh mushrooms labels that should include information to protect consumers' health. STUDY DESIGN: This study reports the microbial load in samples of cultivated and commercialized Agaricus bisporus. Samples were obtained from different shops in Florence, chosen among those products whose labels did not indicate how the product should be consumed. METHODS: From March through May 2014, 20 couples of samples of A. bisporus were acquired in Florence. Microbiological analysis included the quantification of the microbial counts for mesophilic aerobic microorganisms and Enterobacteriaceae, as indicators of hygienic practices during cultivation and manufacturing. The analyses were carried out at two subsequent stages: one immediately (T0) and one at the end of the shelf life (T1), i.e. close to the expiry date stated on the label. RESULTS: The high microbial load observed exceeds the reference values set as acceptable for raw foods in Tuscany and is worse than the ones reported in other studies on this subject. The results are particularly alarming in light of the fact that A. bisporus is usually consumed raw and there is no mandatory specification on the label that informs consumers that the product must be cooked before being consumed. CONCLUSION: This research highlights the importance of adequate and complete information on fresh mushrooms labels, that should include information about the need for sanitization before the consumption, the appropriate storage temperature, and the maximum duration of shelf life. Data obtained could also be useful for food business operators to gather information about the microbial quality of fresh cultivated commercialized mushrooms in order to implement quality controls of the production process and storage conditions.

[Biogenic amines in epigeal spontaneous mushrooms: indicators of quality and freshness?]. / Ammine biogene in funghi epigei spontanei: possibili indi- catori di qualità e freschezza?

Purpose of the present study is to determine the qualitative and quantitative composition of nine biogenic amines (BA) in 153 samples of epigeal spontaneous mushrooms (Boletus edulis and Amanita Caesarea), sampled at large and small food retail shops in the Florence area. Each BA has been identified and quantified using a liquid chromatography system with a reversed phase, C18 column and post-column derivatization with o-oftalaldeide. The results have shown a widespread presence of each amine, although with varying frequency and concentration, and an increasing concentration of tyramine and putrescine in samples with poor organoleptic quality than those in good conditions.

[Biological contamination by micromycetes in dried Boletus edulis: research of aflatoxin B1, B2 G1, G2 and ochratoxin A]. / Contaminazione da funghi filamentosi su Boletus edulis essiccato: ricerca di aflatossina B1, B2 G1, G2 e ocratossina A.

Aim of this survey is to identify those filamentous fungi which parasite Boletus edulis and its group and check the potential presence of secondary metabolites, specifically aflatoxin B1, total aflatoxins and ochratoxin A, in order to assess the risk to consumers' health. Forty samples of dried Boletus edulis, collected by two food industries which distribute the product in many Italian regions, have been analysed. The sampling plan has been conducted from November 2005 to March 2006, collecting 50 g from each commercial category of dried Boletus edulis available in the factory at the time of sampling. All the samples have been tested by visual macroscopic and stereoscopic assays; for some samples--those referred to commercial category presumably at higher risk--we have performed cultural assays as well, typization of isolated micromycetes, extraction and quantification of aflatoxins and ochratoxin A. Mycotoxin detection has been made by HPLC, using the UNI EN 14123 and UNI EN 14132 standard methods, respectively applied to aflatoxins determination in peanuts, pistachios, figs and paprika and to ochratoxin A in barley and coffee. Non pathogenic micromycetes, common in food products, have been frequently observed in cultural assays, while Aspergillus flavus and Aspergillus niger have been found in some samples. However the concentration of aflatoxins was always under the quantification limit. The survey confirm that, if the cold chain is kept throughout the process and the distribution, Boletus edulis and analogue mycetes are not a favourable substratum for the growth and the development of moulds.