抑制火腿中黑曲霉生长及其合成赭曲霉毒素A菌株的筛选、鉴定及生长特性

Screening,Identification and Growth Characterization of Strains Inhibiting the Growth and Synthesis of Ochratoxin A by Aspergillus niger in Hams

赭曲霉毒素A(Ochratoxin A,OTA)是干腌火腿中常见的真菌毒素之一,对消费者健康构成极大威胁。黑曲霉(Aspergillus niger)A-8是贵州盘县火腿中OTA的主要产生菌,为筛选出有效抑制A.niger A-8产OTA的菌株,以具有潜在生防能力的菌株QF3、KF4和RS18为试验菌株,研究其抗真菌活性,NaCl含量对其生长及抗真菌活性的影响,以及3株菌在火腿培养基中抑制A.niger A-8产OTA的能力。对3株菌进行溶血性,形态学和16S rDNA鉴定以及生长特性研究。结果表明,3株菌对A.niger A-8均具有较强抗真菌活性。高浓度(8%)的NaCl能抑制3株菌的生长,但不影响其抗真菌活性。28℃时,3株菌能抑制A.niger A-8在火腿培养基中合成OTA。模拟火腿发酵温度18℃时,只有菌株RS18对A.niger A-8产OTA抑制效果显著(P<0.05)。菌株QF3、KF4和RS18均不具有溶血性。经过鉴定,菌株QF3为耐盐魏斯氏菌(Weissella halotolerans),菌株KF4和RS18为植物乳植杆菌(Lactiplantibacillus plantarum)。3株乳酸菌在17~42℃和pH5~9时都表现出良好的生长特性。综上所述,菌株RS18在火腿发酵温度同样具有抑制OTA产生的活性,有潜力成为防控自然发酵干腌火腿中OTA污染的生防菌。此外,关于耐盐魏斯氏菌抑制黑曲霉生长和OTA合成的效应为首次报道。这项研究为中式干腌火腿自然发酵过程中OTA污染防控提供了重要的生防思路。

Ochratoxin A(OTA)was a common mycotoxin in dry-cured hams,posing a significant threat to consumer health.Aspergillus niger A-8 serves as the primary OTA-producing fungus in ham in Panxian County,Guizhou Province.To identify strains capable of inhibiting OTA production by A.niger A-8,three strains(QF3,KF4,and RS18)were selected to assess their potential biocontrol ability,including antifungal activity,the impact of NaCl content on growth and antifungal activity,and their ability to inhibit OTA production in ham media.Simultaneously,the three strains underwent haemolytic,morphological and 16S rDNA identification,along with growth characterization.Results showed that all three strains exhibited robust antifungal activity against A.niger A-8.Although a high NaCl concentration(8%)hindered their growth,it did not compromise their antifungal efficacy.These strains effectively(P<0.05)suppressed the synthesis of OTA by A.niger A-8 in ham medium.Notably,only strain RS18 inhibited OTA production under simulated ham fermentation temperature conditions,and none exhibited hemolytic activity.Further analysis revealed that strain QF3 belonged to Weissella halotolerans,while strains KF4 and RS18 were identified as Lactiplantibacillus plantarum.All three strains displayed favorable growth characteristics within the temperature range of 17~42℃and pH5~9.In conclusion,RS18 strong antifungal and OTA-producing inhibitory activities,showcasing its potential as a biocontrol bacterium capable of preventing and controlling OTA contamination in naturally fermented dry-cured hams.Additionally,this study reported the inhibitory effect of W.halotolerans on the growth and OTA synthesis of A.niger for the first time,that would provide the valuable insights for novel biocontrol management against OTA contamination during the natural fermentation of Chinese dry-cured hams.