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CONTROL OF AFLATOXIGENIC Aspergillus flavus IN PEANUTS USING NONAFLATOXIGENIC A. flavus, A. niger and Trichoderma harzianum
Get PDFThe effects of nontoxigenic Aspergillus flavus, A. niger and Trichoderma harzianum inoculated into planting media on toxigenic A. flavus infection and its aflatoxin production in peanut kernels at harvest were investigated together with (1) the moisture content of planting media before peanut planting, at the time of inflorescence, and at harvest, (2) the population of aflatoxigenic and nonaflatoxigenic A. flavus, A. niger and T. harzianum in peanut planting media before peanut planting, at the time of inflorescence, and at harvest, (3) the moisture content of peanut kernels at harvest, and (4) toxigenic A. flavus invasion in peanut plant parts (roots, stems, petioles, leaves and flowers) at the time of inflorescence. The fungal isolates were inoculated into planting media at the same time with the planting of peanut seeds. Peanut plants were grown under glasshouse conditions. Treated planting media were inoculated with the combined use of (1) toxigenic and nontoxigenic A. flavus, (2) toxigenic A. flavus and A. niger, and (3) toxigenic A. flavus and T. harzianum. Planting media inoculated only with each fungal isolate and uninoculated planting media were used as controls. Two watering treatments of peanut plants were carried out, i.e. watering until harvest and not watering for 15 days before harvest. The populations of the fungal isolates in the planting media and peanut kernels were determined using dilution method followed by pour plate method; the percentages of toxigenic A. flavus and test fungal colonizations in peanut plant parts were determined using plating method; the moisture content of planting media and peanut kernels were determined using oven method; the aflatoxin content of peanut kernels was determined using Thin Layer Chromatography method. The results indicated that at the time of harvest the decrease in moisture contents of planting media not watered for 15 days before harvest was higher than those watered until harvest. The lowest population of toxigenic A. flavus was in planting media inoculated with the combined use of toxigenic and nontoxigenic A. flavus at the time of inflorescence and at the time of harvest. Toxigenic A. flavus could invade the roots, stems and flowers of peanut plants. The lowest percentage of invasion was on the plant parts which planting media were inoculated with the combined use of toxigenic and nontoxigenic A. flavus. The moisture content of peanut kernels originated from watered plants until harvest were higher than those not watered for 15 days before harvest. The population of toxigenic A. flavus in peanut kernels derived from the plants whose planting media were inoculated with the combined use of toxigenic A. flavus and each test fungi, was lower than those inoculated only with toxigenic A. flavus. It indicated that the test fungi inoculated into planting media could inhibit toxigenic A. flavus infection in peanut kernels. Aflatoxin was only detected in peanut kernels originated from one plant whose planting medium was inoculated only with toxigenic A. flavus and the plant was watered until the time of harvest. Toxigenic A. flavus infection and aflatoxin production were not influenced by planting media which were not watered for 15 days before harvest. Keywords: Biocontrol / Aflatoxigenic / Nonaflatoxigenic / Aspergillus flavus I Aspergillus niger I Trichoderma harzianum I Peanut
ASPERGILLUS FLA VUS INFECTION AND AFLATOXIN CONTAMINATION IN PEANUTS AT VARIOUS STAGES OF THE DELIVERY CHAINS IN CIANJUR REGENCY, WEST JAVA, INDONESIA
Get PDFA survey to obtain information on pre- and postharvest handling of peanuts at farmer, collector, wholesaler and retailer levels, including Aspergillus flavus infection and aflatoxin BI contamination of peanuts collected in Cianjur regency, West Java, was conducted during the harvest period of the wet season of February 2004. The moisture contents and physical qualities of the peanuts were also determined. Thirteen and 40 dry pod samples were collected randomly from 12 farmers and 23 collectors, respectively. Seven dry kernel samples were also collected from collectors. Five and 45 dry kernel samples were collected randomly from 2 wholesalers and 45 retailers in traditional markets, respectively. Thus, a total of 110 dry peanut pod and kernel samples were collected. The results of interviews with farmers, collectors, wholesalers and retailers, and also the moisture contents and physical qualities of the peanuts arc described in this article. The percentages of samples infected by A. flavus were highest at the wholesaler as well as at retailer levels (100%, respectively), followed by those sampled at the collectors (85.0 and 85.7%, respectively), and farmers (84.6%). The mean percentage of infected kernels in infected samples of peanuts collected from retailers was the highest (87.6%), followed by those collected from wholesalers (72.4%), collectors in the form of kernels (23.3%) and pods (17.7%), and farmers (15.2%). The range of aflatoxin BI contents in peanut samples collected from farmers (dry pods), collectors (dry pods), wholesalers (dry pods and kernels) and retailers (dry kernels) were < 3.6 -114.2, < 3.6 -2999.5 and < 3,6 - 34.1, < 3.6 - 6065.9, and < 3.6 - 6073.0 ppb, respectively. The highest aflatoxin B, contents at the wholesaler and retailer levels were 6065.9 ppb (in one sample) and 6073.0 ppb (in one sample), respectively. The percentage of samples contaminated with more than 15 ppb of aflatoxin BI was the highest in peanuts collected from wholesalers (80.0% of samples), followed by retailers (75.6%), farmers (38.5%) and collectors (30.0 and 14.3%). In 1999 Codex Alimcntarius Commission determined that the maximum total aflatoxin content in peanuts intended for further processing is 15 ppb, suggesting that an alarming proportion of peanuts throughout the Indonesian food chain arc in excess of this maximum limit. Key words : ,4,spergillius flavus/Aflatoxin/Peanuts/Cianjur regenc
THE EFFECTS OF MILLING DEGREE AND TYPE OF BAG ON FUNGAL INFECTION AND SOME CHEMICAL CONTENTS OF STORED MILLED RICE
Get PDFThe effects of milling degree and type of bag on fungal infection of stored milled rice were investigated together with some chemical contents (glucose, amylose, protein and total lipid contents), and changes in moisture content. Rice var. IR 64 with different milling degrees (85, 90, 95 and 100%) packed in jute and polypropylene bags (1 kg of milled rice/bag) were stored under laboratory conditions with temperature between 24.3-27.3 C and relative humidity 52.6-81.9% for 3 months. The initial moisture content (m.c.) of milled rice was ± 14%. Three replications (3 bags) were used for each treatment. Each bag was put individually and was arranged randomly on a wooden pallet. The results showed that in general, the increase of milling degree and duration of storage decreased the m.c. Type of bag did not give significant differences on the m.c. Twenty eight fungal species were isolated from rice with different milling degree and bag type during storage. The predominant species was Aspergillus Candidas. Total fungal population decreased with the increase of milling degree and duration of storage. Bag type did not give significant differences on total fungal population. In general, the increase of milling degree increased glucose content. Glucose content in milled rice packed in jute bag was higher than that in polypropylene bag. Glucose content tended to decrease with the increase of storage duration. The increase of milling degree increased amylose content in milled rice. Amylose content of milled rice packed in jute bag was lower than that in polypropylene bag. The increase of storage duration decreased amylose content in milled rice. In general, protein content decreased with the increase of milling degree and duration of storage. 1 type did not give significant differences on protein content. Total lipid content decreased with the increase of milling degree and duration of storage. Total lipid content of milled rice packed in jute bag was lower than that in polypropylene bag, but based on chemical analysis the difference was not significant. Based on statistical analyses, correlation between the m.c. and total lipid content with total fungal population was positive. There was no correlation between glucose, amylose and protein contents with total fungal population. Rice with high milling degree can be stored safely for long period, but it has low chemical (nutritional) contents. Key words:  Milling degree/Bag type/Fungal infection/Chemical content/Milled rice
ANTAGONISTIC EFFECT OF THREE FUNGAL ISOLATES TO AFLATOXIN-PRODUCING^spergiY/HS/JavHS
Get PDFAflatoxin contamination in preharvest peanuts can be controlled among others by using antagonistic fimgi to aflatoxin-producing fungi. Aspergillus flavus is one of the fungal species where certain strains can produce aflatoxin. Informations regarding the type of interactions between antagonistic fungi and toxigenic A. flavus, and the effects of culture filtrates of the test fungi on the growth and aflatoxin production of toxigenic A. flavus are necessary, before antagonistic fungi could be used as biocontrol agent. Three fungal isolates (nontoxigenic A. flavus BIO 2127, A. niger BIO 2129 and Trichoderma harzianum BIO 19130) were tested for their antagonistic properties against toxigenic A. flavus BIO 2132 using direct and indirect confrontation methods. On direct confrontation method, four kinds of agar media were used, i.e PDA (Potato Dextrose Agar), MEA 1% (Malt Extract Agar 1%), SMKYA (Sucrose 200 g, MgSO47H2O 0.5 g, KNO3 3 g, yeast extract 7 g, and block agar AA 20 g), and the mixture of MEA 1 % + SMKYA (1:1). The results indicated that the type of interactions between toxigenic A. flavus either with nontoxigenic A. flavus or with T. harzianum was B type. In this type of interaction, the growth of both toxigenic A. flavus and the test fungi inhibited each other (mutual inhibition) with the zone of inhibition 2 mm. Culture filtrates derived from nontoxigenic A. flavus and A. niger grown on ME 1%, SMKY and ME 1% + SMKY inhibited the growth (based on dry weight) of toxigenic A. flavus, except culture filtrates derived from T. harzianum grown on SMKY and ME 1% + SMKY media stimulated the growth of toxigenic A. flavus. Culture filtrates of nontoxigenic A. flavus, A. niger and T. harzianum inhibited aflatoxin B\ production of toxigenic A. flavus. Culture filtrates of A. niger and T. harzianum with conidial concentrations of IxlO6, 2xl06 and 3xl06 per ml inhibited aflatoxin B, production up to 100%. The percentage of inhibition of aflatoxin Bi production increased with the increase of conidial concentrations of nontoxigenic A. flavus. The highest percentage of inhibition of aflatoxin BI production (62.5%) was obtained from conidial concentration of 3xl06 per ml. Aspergillus niger was the most potential fungus in inhibiting the growth of toxigenic A. flavus, either on agar media or on culture filtrates of test fungi. Culture filtrate of A. niger was also the most potential filtrate in inhibiting aflatoxin BI production of toxigenic A. flavus.Keywords:   Antagonistic effect / Aspergillus flavus I Aspergillus niger I Trichoderma harzianum I aflatoxi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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