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Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is being increasingly considered as the main causal agent of Balkan endemic nephropathy (BEN), a fatal kidney disease associated with the end stage of urothelial tumours. However, despite the considerable amount of data, it is still controversial whether OTA plays a causative or only a subordinate role in the induction of this human nephropathy. Tunisia for years had to confront a very similar human nephropathy, which is tentatively called chronic interstitial nephropathy of unknown cause. This study tends firstly to consolidate the suspected link between this Tunisian chronic interstitial nephropathy (CIN) of unknown cause and the presence of OTA in the blood and food of such patients, and second to enlighten the endemic character of this particular nephropathy. Therefore, in four consecutive inquiries, performed within the period 1991-2000, blood and food OTA contaminations were assayed and compared for 954 nephropathy patients and 205 healthy subjects from the Tunisian general population. This survey was also designed to show that, although the whole population is likely to be exposed to OTA, specific people living in conditions showing similarities with the Balkans do have a kidney disease apparently linked to ochratoxin in food. The results showed that the highest incidences were found in patients with CIN of unknown cause. Indeed, the percentages of OTA-positive samples ranged from 93% to 100%, whereas it was only from 62% to 82% in healthy subjects. Mean OTA concentrations were also higher in patients with CIN of unknown cause than in controls (44.4±-19 mg/L to 55.6±-19 mg/L as opposed to 1.22±-1.2 mg/L to 3.35±-2.32 mg/L, respectively). This study emphasizes further the implication of OTA on this particular human nephropathy and underlines the probable causative role of OTA in the onset of this disease. It is important to note that the highest levels of food OTA contamination were found in the group presenting with CIN of unknown cause, indicating that, similar to the case in the Balkans, people are exposed to OTA essentially by their food.

Processed meat products frequently suffer from fungal and mycotoxin contamination, mostly ochratoxin A (OTA). Penicillium nordicum is considered responsible for this contamination, but Aspergillus westerdijkiae has recently been associated with high levels of OTA in meat products. Several biocontrol agents have been tested against P. nordicum growth and OTA production in meat products, but A. westerdijkiae has not been considered. The aim of this work was to evaluate in vitro the effect of a commercial starter culture used in sausage fermentation and of sausage-native yeasts on OTA production by A. westerdijkiae, as compared with the highly studied P. nordicum, in meat-based culture media. Four representative yeasts isolated from dry-cured sausage and a commercial starter culture were coinoculated with both fungi in different meat-based media, under varying conditions. Fungal growth was determined by measuring colony diameter, and OTA production was quantified by HPLC-FLD. A. westerdijkiae was significantly stimulated to produce OTA under all tested conditions, and, in ham, OTA production by P. nordicum was stimulated by co-culture with the starter culture. In conclusion, endogenous or added microorganisms enrolled in fermentation or in biocontrol in meat products seem to exert varying responses on different ochratoxigenic fungi, thus leading to unforeseen safety problems.

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BackgroundThe long-lasting and abundant blooming of Pelagia noctiluca in Tunisian coastal waters compromises both touristic and fishing activities and causes substantial economic losses. Determining their molecular mode of action is, important in order to limit or prevent the subsequent damages. Thus, the aim of the present study was to investigate the propensity of Pelagia noctiluca venom to cause oxidative damage in HCT 116 cells and its associated genotoxic effects.ResultsOur results indicated an overproduction of ROS, an induction of catalase activity and an increase of MDA generation. We looked for DNA fragmentation by means of the comet assay. Results indicated that venom of Pelagia noctiluca induced DNA fragmentation. SDS-PAGE analysis of Pelagia noctiluca venom revealed at least 15 protein bands of molecular weights ranging from 4 to 120 kDa.ConclusionOxidative damage may be an initiating event and contributes, in part, to the mechanism of toxicity of Pelagia noctiluca venom.