ชื่อวิทยานิพนธ์:  Enumeration of Ochratoxin A Producing Fungi in Thai Coffee Beans
สถานที่ทำงานปัจจุบัน: คณะวิทยาศาสตร์และเทคโนโลยีอุตสาหกรรม มหาวิทยาลัยสงขลานครินทร์
วิทยาเขตสุราษฎร์ธานี

คณะกรรมการที่ปรึกษา:
                1. ผศ.ดร.วราภา  มหากาญจนกุล                     ประธานกรรมการที่ปรึกษาวิทยานิพนธ์
                2. ผศ.ดร.รัชนี  ฮงประยูร                                 กรรมการวิชาเอก
                3. ผศ.ดร.ธนะบูลย์  สัจจาอนันตกุล                  กรรมการวิชาเอก
                4. Dr. Robert  A.  Samson                              กรรมการวิชาเอก  

ผลงานตีพิมพ์:   

• Noonim, P., W. Mahakarnchanakul, J. C. Frisvad and R. A. Samson. 2008. Isolation, identification and
  toxigenic potential of ochratoxin A-producing Aspergillus species from coffee beans grown         
  two regions of Thailand. International Journal of Food Microbiology.
  Impact factor = 2.581
• Noonim, P., W. Mahakarnchanakul, J. Varga, J. C. Frisvad and R. A. Samson. 2008. Two novel
  species of Aspergillus section Nigri from Thai coffee beans. International Journal of
  Systematic and Evolutionary Microbiology 58(7): 1727-1734
  Impact Factor = 2.662
• oonim, P., W. Mahakarnchanakul, J. Varga and R. A. Samson. 2008. “Aspergilli and ochratoxin A in  coffee. Aspergillus in the Genomic Era: 213-231.
• errone, G., A. Susca, G. Cozzi, K. Ehrlich, J. Varga, J. C. Frisvad, M. Meijer, P. Noonim, W.        
  Mahakarnchanakul and R. A. Samson. 2007. Biodiversity of Aspergillus species in some important
  agricultural products.” Studies in Mycology 2007(59): 53-66.
  Impact Factor = 5.923

บทคัดย่อ:

           Ochratoxin A contamination of coffee is a worldwide problem and has been studied in different countries and on different types of coffee beans. 64 Thai coffee sampled in 2006-2007 were studied, originating from (1) Arabica coffee (Coffea arabica) from Chiang Mai Province (the Northern Thailand) and (2) Robusta coffee (Coffea canephora var. robusta) from Chumphon province (the Southern Thailand). Remarkable differences in the ecology of the ochratoxigenic Aspergillus species were found.  Arabica samples from the North had an average of 77.5% incidence of contamination from Aspergillus spp. in section Circumdati with A. westerdijkiae and A. melleus as the predominant species. The others were A. steynii and A. sclerotiorum. A. ochraceus was not detected in any samples. Black Aspergilli with A. niger and relatives as the predominant species were found in 75% of the samples. A. carbonarius was not recovered. Other Aspergilli were A. flavus, A. tamarii, A. candidus, etc.  All Robusta samples from the South were infected with black Aspergilli with A. carbonarius and A. niger as predominant species.  The second predominant Aspergilli belonged to section Flavi.  The diversity of the fungal population is probably explained by the differences of the geographical origin of the coffee, coffee cultivar, and processing method used.  In this study two new species of black Aspergilli: A. sclerotiicarbonarius, a biseriate-A carbonarius-related species, from only the Southern Thailand and A. aculeatinus, a uniseriate-A. aculeatus-related species, from both the Northern and the Southern Thailand were also discovered and described according to polyphasic taxonomic approach.  Representative isolates of section Circumdati (52) and Nigri (82) were determined for ochratoxin production by HPLC. Among the yellow Aspergilli, A. steynii was the best ochratoxin producer, following with A. westerdijkiae, while A. melleus was a poor producer. In section Nigri, only A. carbonarius and A. niger were found to produce ochratoxins. Being screened with RidascreenÒ Ochratoxin A ELISA kits, 98% of coffee bean samples were contaminated with ochratoxin A at levels varied from 0.6-5.49 ppb (for Arabica) and 1.3-26.69 ppb (for Robusta coffee beans)