Risk analysis of the main mycotoxins from food in children
Raiola, Assunta (2011) Risk analysis of the main mycotoxins from food in children. [Tesi di dottorato] (Inedito)
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Mycotoxins are secondary metabolites produced by fungi that may contaminate all stages of the food chain and that are toxic or carcinogenic to animals and humans. In this PhD thesis, several aspects of risk analysis of mycotoxins are treated. In particular the studied mycotoxins included: Patulin (PAT), Deoxynivalenol (DON), Ochratoxin A (OTA), Aflatoxin B1 (AFB1), Aflatoxin M1 (AFM1), and the attention is focused on hazard for infants and children that represent more sensitive and vulnerable categories respect to adults. The first study case (chapter 3) treats with risk management to control blue mould on apples whose products of industrial transformation are widely consumed by whole population, above all children. The aim of the study was to test compatibility of the biocontrol yeasts (Rhodosporidium kratochvilovae LS11 and Cryptococcus laurentii LS28) with the recently developed fungicides boscalid (BOSC), cyprodinil (CYPR) and fenhexamid (FENH). The fungicide thiabendazole (TBZ) was used as the control. After 7 days of storage, the integrated treatment based on biocontrol agents (BCAs) with BOSC or CYPR resulted in a signiﬁcant rot reduction (as much as 98%). Integrated treatments (BCAs + BOSC or CYPR) resulted in lower fungicide residues and PAT contamination in apples. During apple products manufacturing, the formation of undesirable products like 5-hydroxymethylfurfural (HMF) that is a marker of thermal processing can occur. In the second topic (chapter 4) apple juice and puree were prepared, artificially contaminated with PAT and submitted to a heat treatment to evaluate PAT’s reduction. HMF’s level was also detected in both juice and puree. Then, uncontaminated apple products samples (n=7) included juices, nectars and purees belonging to different commercial brands were collected, artificially contaminated with PAT at 50µg/l (limit established for PAT in juices) and 25 µg/kg (limit established for PAT in purees), digested with an in vitro gastrointestinal digestion protocol in children and bioaccessibility values (%) were calculated. After heat treatment, the evidenced PAT’s loss was of 1.41 ± 0.52% in purees whereas it was of 62.62 ± 2.53% in the juices. HMF’s level was 0.045±0.002µg/ml in puree and 8.3 ± 0.06 µg/ml in the juices. These differences can be related to the major protection of mycotoxin in semi-solid matrix, characterized by a major viscosity. Relatively to results of bioaccessibility, juices with pulp showed values of 70.89 ± 4.93% and 55.69 ± 4.73%, purees showed levels of 67.30 ± 10.76% and 58.15 ± 5.50% whereas nectar and clarified juices showed percentages of 38.88 ± 2.42%, 28.59 ± 0.46% and 25.28 ± 0.61% respectively. The physical structure of clarified products could have favored the action of digestive enzymes. In the third topic (chapter 5) twenty-seven samples of dried pasta characterized by size, packaging and marketing intended for children consumption were collected and analyzed for OTA, AFB1 and DON determination. The samples that showed the highest amounts of one of the mycotoxins were cooked, digested with an in vitro gastrointestinal protocol and bioaccessibility values were calculated. Seven of the twenty-seven samples exceeded from 120% to 225% the legal limit of 200 µg/kg for DON fixed for processed cereal-based baby foods by an European Regulation; all the collected samples were under the OTA legal limit (0.05 µg/kg) fixed by the European Regulation and none of the samples was contaminated by AFB1 over the instrumental limit of detection of 0.10 µg/kg. The mean value of gastric bioaccessibility verified for the DON resulted of 23.1%, whereas mean duodenal bioaccessibility was 12.1%. Considering only the samples treated with the child digestion the mean DON duodenal bioaccessibility data was of 9.7%. Therefore, the DON could interact with the intestinal epithelium cells at concentrations of 3.4-18.9 µg/kg and these levels are cytotoxic on several cell lines. The fourth topic (chapter 6) treats with the exposure assessment to AFM1 by breast milk collected from 50 lactating mothers in three senatorial districts of Ogun State, Nigeria. The relationship with dietary AFB1 exposure was also studied. AFM1 was detected in 41 (82%) of breast milk samples ranging from below limit of detection (<LOD) to 92.14 ng/l (mean = 15.9 ng/l). Nine (18%) of the breast milk samples had AFM1 below the detectable limit while eight (16%) of the samples had levels exceeding the European standard limit. The highest AFM1 risk was found in Ogun Central senatorial district. The level of AFB1 contamination in the foods consumed by the mothers were generally low with foodstuffs from Ogun Central senatorial district having a significantly higher (p<0.05) mean (0.33 µg/kg) than those collected from Ogun East senatorial district (0.18 µg/kg) and Ogun West (0.16 µg/kg). There was a significantly (p<0.05) positive correlation between the AFB1 consumed in foodstuffs by the lactating mothers and the AFM1 detected in their breast milk.
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