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edu/mhuss/Aspergillus flavus pict.jpg

By:Rahayu WP

Department of Food Science and Technology, Bogor Agricultural University

Mycotoxin is widely known as one cause of the foodborne disease, produced by toxigenic fungi. Its prevalence becomes higher with the availability of supporting conditions such as proper climatic changes, plentiful substrates, and minimum controls. Any country should be aware about this high risk potency in order to maintain food safety and food security by knowing the mycotoxin, the affected commodities, the fungal sources, and  the toxicity effect to human or animal. Indonesia has made some regulations regarding the contamination of mycotoxin to food or feedstuff, including Aflatoxin, Fumonisin, Deoxynivalenol (DON), Ochratoxin, and Patulin (PAT). Besides controlling through regulations, many studies  controlling mycotoxin have also been done throughout the world.   The using of microorganism or metabolite compounds produced by microorganism as biological agent has many advantages such as mild reaction conditions, target specificity, efficiency and environmental friendly. Some microbial strains has been developed as commercial biological agent product including Aspergillus flavus AF36, A. flavus strain NRRL21882, etc. The microbial characteristic used for biological agent should be evaluated including the inability to produce toxic substance, the tendency to multiply, colonize, survive, the safety, and applicability to the environment. Studies related to mycotoxin biocontrol by using microorganism can be focused on (1) the effect to the mycotoxin, (2) the growth of microorganism, or (3) the application to food both raw material and processed products. Consideration to combine more than one species of microorganism instead of a single species also has been taken to gather the possibility of achieving more effective.  For example, Yeast (S. cerevisiae) has been used together with bacteria (LAB) to take control on mycotoxin produced by some fungi. Further studies are still needed to develop the possibility of other biological control agents and the effect of their application, which in the next have the potency to be developed as manufacturing products.

Keywords: alternatives, advantages, biological agents, mycotoxin biocontrol

Presented at International Conference on Mycological Aspects of Food and Feed Safety, Yogyakarta, 27-28 June 2013


[abstract] EFFECT of KEBAR GRASS (Biophytum petersianum) LEAF EXTRACT on THE GROWTH AND STRUCTURE of AFLATOXIGENIC Aspergillus flavus


Source: Private collection

By: Lisangan MM1,2, Syarief R1, Rahayu WP1,Dharmaputra OS3,4

1 Faculty of Agricultural Engineering and Technology, Bogor Agricultural University
2  Faculty of Agricultural and Agricultural Technology, The State University of Papua
Faculty of Mathematics and Natural Sciences, Bogor Agricultural University
4Southeast Asian Regional Centre for Tropical Biology (SEAMEO BIOTROP)- Indonesia

The objective of this study was to investigate the chemical composition and antifungal activity of kebar grass polar extract and its effect on the mycelial growth, conidiation and  morphological structure of two isolates of aflatoxigenic Aspergillus flavus, i.e. isolates BCCF0219 and AF1. A total of 64 components were identified using pyrolysis/gas chromatography/mass spectrometry (Py/GC/MS), consisting of a class of carboxylic acids (7.81%), amina (1.56%), phenolics (26.56%), terpenes (15.60%), alcohols (10.94%), hydrocarbons compounds (20.3 %), benzene derivatives (6.25%), carbohydrate derivatives (4.69%), steroidal saponin (1.56%),  haloalkane (1.56%), and sterols (3.13%).In the bioassay, the two isolates of A. flavus were cultured on three  types of model media, i.e. fat-enriched medium, protein-enriched medium and carbohydrate-enriched medium containing five concentrations (12, 14, 16, 18, and 20 mg/mL) of kebar grass polar extract.  The changes of hyphae structure and conidiation were observed usingScanning Electron Microscopy (SEM). The results showed that the percentage of growth inhibition of A. flavus isolate BCCF0219 caused by kebar grass polar extracts at a concentration of 14 mg/mL was 95.5% (in fat-enriched medium), whereas at a concentration of 12 mg / mL was 95.7% (in carbohydrate-enriched medium) and a concentration of 14 mg/mL was 91.0% (in protein-enriched medium).  The percentage of growth inhibition of A. flavusisolate AF1 caused by the extract at  a concentration of 16 mg/mL was 100% (in fat-enriched medium),while at a concentration of 12 mg / mL was 91.4% (in carbohydrate-enriched medium) and at a concentration of 16 mg/mL was 94.3% (in protein-enriched medium). A marked retardation in conidial production of the fungus was noticed in relation to the inhibition of mycelial growth. Under scanning electron microscopy, deformation of hyphae tips, formation of short branches, thinner hyphae, folded hyphae and collapse of entire hyphae were the major changes observed.  Morphological alterations might be due to the effect on cell permeability through the direct interaction between kebar grass extract and the fungal plasma membrane. These findings indicate the potential of  kebar grass leaf extract in preventing aflatoxigenic A. flavus infection  and minimize aflatoxin contaminationin stored food and feedstuff.


Keywords: Aspergillus flavus, Biophytum petersianum, growth inhibitor, morphological structure, Scanning Electron Microscopy

Presented at International Symposium on Tropical Fungi, Mikoina. Bogor 10-11 September 2013





Source: private collection

By:  Palupi NS 1),  Setyawardani T2) and Rahayu WP1)

1)Department of Food Science and Technology  and SEAFAST Center- Bogor Agricultural University
2)Faculty of Animal Science, Jenderal Soedirman University

Probiotic is live non-pathogenic microorganisms that give beneficial effects on health when they are administered in adequate amounts.  The objective of the study was to evaluate the influence L. rhamnosus TW2 and L. plantarum TW14 as well as cheese containing the probiotics on the profiles of microflora, morphological profile of ileum and caecum, lymphocyte proliferation and IgA levels in mice. Male SD rats was fed with the probiotics or cheese containing the probiotics for 10 days, infected with S. Typhimurium for 3 days, and continued to be fed with or without the probiotics or the cheese. Additionally a group of mice with standard feeding was used as control group. The results showed that the number of total lactic acid bacteria in the ileum and caecum in probiotic fed mice was higher than control, whereas the number of S. Typhimurium was lower. The growth of S. Typhimurium was completely inhibited when the mice were continuously given probiotics post-infection. Treatment of probiotic isolate was able to improve the number of lymphosite cellsduring the first 10 days, during infection with S. Typhimurium, and postinfection. Treatment of probiotic isolate was able to improve sIgA at the time of S. Typhimurium intervention. In conclusion, mixed isolates of L. rhamnosus TW2 and L. plantarum TW14 and cheese containg the probiotics were able to show preventive and remedial functions during S. Typhimurium ATCC 14028 infection, thus demonstrate the potential immunomodulatory.

Key words: Immunomodulatory, IgA, L. rhamnosus TW2, L. plantarum TW14, probiotic

Presented at 13th Asean Food Conference, SIFST (Singapore Institute of Food Science & Technology), Singapore 9-11 September 2013