Distribution and Mycotoxigenic Potential of Aspergillus Section Nigri Species in Naturally Contaminated Almonds

In a previous study, inedible almond pick-out samples were assayed for aflatoxin and aflatoxigenic Aspergillus species. These samples contained high populations of black-spored Aspergillus section Nigri species. To investigate whether these species may contribute to the total potential mycotoxin content of almonds, Aspergillus section Nigri strains were isolated from these samples and assayed for ochratoxin A (OTA) and fumonisin B2 (FB2). The majority of isolates (117 strains, 68%) were identified as Aspergillus tubingensis, which do not produce either mycotoxin. Of the 47 Aspergillus niger and Aspergillus awamori isolates, 34 strains (72%) produced FB2 on CY20S agar, and representative strains produced lower but measurable amounts of FB2 on almond meal agar. No OTA-producing strains of Aspergillus section Nigri were detected. Almond pick-out samples contained no measurable FB2, suggesting that properly dried and stored almonds are not conducive for FB2 production by resident A. niger and A. awamori populations. However, 3 of 21 samples contained low levels (<1.5 ng/g) of OTA, indicating that sporadic OTA contamination may occur but may be caused by OTA-producing strains of other Aspergillus species.

Download Full-text

Incidence of Fumonisin B2 Production within Aspergillus Section Nigri Populations Isolated from California Raisins

Journal of Food Protection ◽

10.4315/0362-028x.jfp-10-412 ◽

2011 ◽

Vol 74 (4) ◽

pp. 672-675 ◽

Cited By ~ 15

Author(s):

JEFFREY D. PALUMBO ◽

TERESA L. O'KEEFFE ◽

JEFFERY A. McGARVEY

Keyword(s):

Aspergillus Niger ◽

Ochratoxin A ◽

Pcr Amplification ◽

Biosynthetic Genes ◽

Putative Orthologs ◽

Aspergillus Section Nigri ◽

Field Isolates ◽

Potential Sources ◽

Fumonisin B2 ◽

Aspergillus Section

Fungi belonging to Aspergillus section Nigri occur frequently and in high populations on grapes. Species within this section include Aspergillus niger, A. tubingensis, and A. carbonarius, and they are potential sources for mycotoxins including ochratoxin A and fumonisin B2 (FB2) in grapes and grape products. Aspergillus section Nigri strains were isolated from California raisins to examine the frequency and extent of FB2 production. Of 392 strains isolated, 197 strains were identified as A. niger, 131 of which produced FB2. These strains produced from 1.2 to 27 μg/ml FB2 in culture. PCR amplification of fum1 and fum19 gene fragments showed that all FB2-producing strains and nearly all nonproducing strains of A. niger contain these genes. An additional 175 strains were identified as A. tubingensis, none of which produced FB2. PCR with fum1 and fum19 primers amplified gene fragments of 14 and 25% of A. tubingensis strains, respectively, suggesting that putative orthologs of A. niger fumonisin biosynthetic genes might occur in A. tubingensis. These results indicate that FB2 production is common among field isolates of A. niger and suggest that the potential for FB2 contamination of California raisins should be addressed further.

Download Full-text

Isolation and Identification of Aspergillus Section Nigri, and Genotype Associated with Ochratoxin A and Fumonisin B2 Production in Garlic Marketed in Brazil

Current Microbiology ◽

10.1007/s00284-020-01915-6 ◽

2020 ◽

Vol 77 (7) ◽

pp. 1150-1158 ◽

Cited By ~ 1

Author(s):

Dayane Oscarina Aparecida Vanzela ◽

Fernanda Pelisson Massi ◽

André Luiz Martinez de Oliveira ◽

Maria Helena Pelegrinelli Fungaro ◽

Daniele Sartori

Keyword(s):

Ochratoxin A ◽

Isolation And Identification ◽

Aspergillus Section Nigri ◽

Fumonisin B2 ◽

Aspergillus Section

Download Full-text

Occurrence of Ochratoxin A Contamination and Detection of Ochratoxigenic Aspergillus Species in Retail Samples of Dried Fruits and Nuts

Journal of Food Protection ◽

10.4315/0362-028x.jfp-14-471 ◽

2015 ◽

Vol 78 (4) ◽

pp. 836-842 ◽

Cited By ~ 23

Author(s):

JEFFREY D. PALUMBO ◽

TERESA L. O'KEEFFE ◽

YVONNE S. HO ◽

CARLO J. SANTILLAN

Keyword(s):

European Union ◽

Ochratoxin A ◽

The United States ◽

Aspergillus Species ◽

The European Union ◽

Dried Fruits ◽

Tree Nuts ◽

Low Levels ◽

Contamination Levels ◽

Potential Contaminant

Ochratoxin A (OTA) is a mycotoxin produced by several species of Aspergillus and Penicillium and is a potential contaminant of a wide variety of food products. To determine the incidence of OTA contamination in dried fruits and tree nuts, retail packaged and bulk raisins, dates, figs, prunes, almonds, pistachios, and walnuts were collected from small and large supermarkets in seven areas of the United States between 2012 and 2014. Of the 665 samples analyzed, OTA was detected in 48 raisin samples, 4 fig samples, 4 pistachio samples, and 1 date sample. OTA contamination levels ranged from 0.28 to 15.34 ng/g in dried fruits and 1.87 to 890 ng/g in pistachios; two raisin samples and one pistachio sample exceeded the European Union regulatory limit of 10 ng/g. PCR detection of potential OTA-producing Aspergillus species revealed the presence of A. niger, A. welwitschiae, and A. carbonarius in 20, 7, and 7 of the 57 OTA-contaminated samples, respectively. However, OTA-producing A. carbonarius was isolated from only one raisin sample, and no other OTA-producing Aspergillus species were found. These results suggest that raisins are more frequently contaminated with low levels of OTA than are other dried fruits and nuts and that Aspergillus species are the likely source of that contamination.

Download Full-text

Influence of light on growth, conidiation and the mutual regulation of fumonisin B2 and ochratoxin A biosynthesis by Aspergillus niger

World Mycotoxin Journal ◽

10.3920/wmj2011.1364 ◽

2012 ◽

Vol 5 (2) ◽

pp. 169-176 ◽

Cited By ~ 12

Author(s):

F. Fanelli ◽

M. Schmidt-Heydt ◽

M. Haidukowski ◽

R. Geisen ◽

A. Logrieco ◽

...

Keyword(s):

Aspergillus Niger ◽

Ochratoxin A ◽

Blue Light ◽

Short Wave ◽

Light Conditions ◽

Dark Incubation ◽

Mutual Regulation ◽

Blue Wavelength ◽

Fumonisin B2 ◽

Dark Production

Aspergillus niger is a fungus able to produce the carcinogenic mycotoxins ochratoxin A (OTA) and fumonisins. We analysed the influence of light of various wavelengths on growth, conidiation, fumonisin B2 (FB2) and OTA biosynthesis by A. niger ITEM 7097. Light from both sides of the spectrum, from long (627 nm) to short wavelengths (470-455 nm), had a stimulating effect on growth, with the highest stimulation under blue (455 nm, 1,700 Lux) and short-wave blue light (390 nm). Conidiation was reduced by 40% under a short blue wavelength (455 nm, 200 Lux), but strongly promoted under light at an even shorter wavelength (390 nm), with an increase of about 200 fold in comparison to the dark. Production of FB2 and OTA was mutually regulated by light. FB2 production was promoted under light conditions: red and blue light in particular increased FB2 biosynthesis by 40%. Conversely, OTA production was greatly inhibited under red and blue light in comparison to dark incubation, with a mean reduction of about 40 fold, indicating a reverse regulation of both biosynthetic pathways. Incubation under a 390 nm wavelength repressed the production of both toxins to non-detectable levels.

Download Full-text

Isolation, Molecular Identification, and Mycotoxin Production of Aspergillus Species Isolated from the Rhizosphere of Sugarcane in the South of Iran

Toxins ◽

10.3390/toxins12020122 ◽

2020 ◽

Vol 12 (2) ◽

pp. 122 ◽

Cited By ~ 1

Author(s):

Maryam Tavakol Noorabadi ◽

Valiollah Babaeizad ◽

Rasoul Zare ◽

Bita Asgari ◽

Miriam Haidukowski ◽

...

Keyword(s):

Genetic Diversity ◽

Aspergillus Terreus ◽

Plant Pathogens ◽

Fungal Species ◽

Aspergillus Species ◽

Aspergillus Tubingensis ◽

Ecological Role ◽

The South ◽

Mycotoxin Production ◽

Aspergillus Section

Knowledge of the genetic diversity detected among fungal species belonging to the genus Aspergillus is of key importance for explaining their important ecological role in the environment and agriculture. The current study aimed to identify Aspergillus species occurring in the rhizosphere of sugarcane in the South of Iran, and to investigate their mycotoxin profiles. One-hundred and twenty-five Aspergillus strains were isolated from the soil of eight major sugarcane-producing sites, and were molecularly identified using sequences of partial -tubulin (benA) and partial calmodulin (CaM) genes. Our molecular and phylogenetic results showed that around 70% of strains belonged to the Aspergillus section Nigri, and around 25% of species belonged to the Aspergillus section Terrei. Species belonging to both sections are able to produce different mycotoxins. The production of mycotoxins was measured for each species, according to their known mycotoxin profile: patulin (PAT) and sterigmatocystin (STG) for Aspergillus terreus; ochratoxin A (OTA) and fumonisins for Aspergillus welwitschiae; and OTA alone for Aspergillus tubingensis. The data showed that the production of OTA was detected in only 4 out of 10 strains of A. welwitschiae, while none of the A. tubingensis strains analyzed produced the mycotoxin. Fumonisins were produced by 8 out of 10 strains of A. welwitschiae. Finally, none of the 23 strains of A. terreus produced STG, while 13 of them produced PAT. The occurrence of such mycotoxigenic plant pathogens among the fungal community occurring in soil of sugarcane fields may represent a significant source of inoculum for the possible colonization of sugarcane plants, since the early stages of plant growth, due to the mycotoxin production capability, could have worrisome implications in terms of both the safety and loss of products at harvest.

Download Full-text