Giorni P, Magan N, Pietri A, Bertuzzi T, Battilani P
Istituto di Entomologia e Patologia Vegetale, Università Cattolica del Sacro Cuore, Via E. Parmense 84, 29100 Piacenza, Italy.
Int J Food Microbiol. 2007 Feb 15;113(3):330-8. doi: 10.1016/j.ijfoodmicro.2006.09.007. Epub 2006 Nov 7.
In 2003, for the first time in Italy, significant problems arose with colonization and contamination of maize destined for animal feed with Aspergillus section Flavi and aflatoxins (AFs). This resulted in milk and derived products being contaminated with AFM(1) at levels above the legislative limit. There was little knowledge and experience of this problem in Italy. The objectives of this research were thus to study the populations of Aspergillus section Flavi in six northern Italian regions and obtain information on the relative role of the key species, ability to produce sclerotia, production of the main toxic secondary metabolites, aflatoxins and cyclopiazonic acid, and tolerance of key environmental parameters. A total of 70 strains were isolated and they included the toxigenic species A. flavus and A. parasiticus. A. flavus was dominant in the populations studied, representing 93% of the strains. Seventy percent of strains of Aspergillus section Flavi produced AFs, with 50% of strains also producing cyclopiazonic acid. Sixty-two percent of A. flavus strains and 80% of A. parasiticus were able to produce sclerotia at 30 degrees C. Using 5/2 agar, only 1 strain developed S sclerotia and 19 L sclerotia. With regard to ecological studies, growth of Aspergillus section Flavi was optimal at between 25 and 30 degrees C, while AFB(1) production was optimal at 25 degrees C. Regarding water availability (water activity, a(w)), 0.99 a(w) was optimal for both growth and AFs production, while the only aflatoxin produced in the driest condition tested (0.83 a(w)) was AFB(1). This information will be very useful in identifying regions at risk in northern Italy by linking climatic regional information to levels of fungal contamination present and potential for aflatoxin production in maize destined for animal feed. This would be beneficial as part of a prevention strategy for minimising AFs in this product.
2003年，意大利首次出现重大问题，即用于动物饲料的玉米被黄曲霉群和黄曲霉毒素（AFs）污染。这导致牛奶及衍生产品中AFM(1)的污染水平超过法定限值。意大利对这个问题的了解和经验很少。因此，本研究的目的是研究意大利北部六个地区的黄曲霉群种群，并获取有关关键物种的相对作用、产生菌核的能力、主要有毒次生代谢产物黄曲霉毒素和环匹阿尼酸的产生以及对关键环境参数的耐受性等信息。总共分离出70株菌株，其中包括产毒物种黄曲霉和寄生曲霉。在所研究的种群中，黄曲霉占主导地位，占菌株的93%。70%的黄曲霉群菌株产生AFs，50%的菌株还产生环匹阿尼酸。62%的黄曲霉菌株和80%的寄生曲霉菌株能够在30℃下产生菌核。使用5/2琼脂，只有1株产生S型菌核，19株产生L型菌核。关于生态学研究，黄曲霉群在25至30℃之间生长最佳，而AFB(1)的产生在25℃时最佳。关于水分可利用性（水分活度，a(w)），0.99 a(w)对生长和AFs产生均最佳，而在测试的最干燥条件（0.83 a(w)）下产生的唯一黄曲霉毒素是AFB(1)。通过将气候区域信息与存在的真菌污染水平以及用于动物饲料的玉米中黄曲霉毒素产生的可能性联系起来，这些信息对于识别意大利北部的风险区域将非常有用。作为尽量减少该产品中AFs的预防策略的一部分，这将是有益的。
