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Journal : Jurnal Agritech

Pediococcus acidilactici F-11 Penghasil Bakteriosin sebagai Agensia Biokontrol Escherichia coli dan Staphylococcus aureus pada Sayuran Segar Simpan Dingin

Agritech Vol 24, No 3 (2004)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Our survey indicated that fresh vegetables contained. high population of microorganisms including pathogenic Staphylococcus aureus. Washing procedures, including the addition of sanitizes to the wash water have not been effectively in reduction of the number of microorganisms. Currently, there is interest in possible use bacteriocin producer of lactic acid bacteria as biocontrol agents to ensure safety of minimally processed, refrigerated (MPR) foods which are not acidified, including fruits and vegetables. Our previous result, indicated that Pediococcus acidilactici F-11 (PAF-11) produced bacteriocin with wide spectrum activity. Objectives of this research was to study the potency of PAF-I 1 as biocontrol agent to inhibit the growth of pathogenic bacteria occurred in ready to eat fresh vegetables, i.e., paprika, lettuce, carrot. The results showed that PAF-11 was able to inhibit the growth of naturally present coliform and Staphylococcus significantly, as well as that of tested bacteria of E. coil and S. aureus which were inoculated into paprika and carrot. PAF-11 was able to grow at these two vegetables, and their population were increased about I log cycle. Bacteriocin activity produced by PAF-11 was positively detected from these two vegetables inoculated with these bacteria. However, there was no inhibition activity of PAF-11 against naturally present coliform and Staphylococcus, as well as inoculated E. coil and S. aureus on lettuce. Bacteriocin activity produce by PAF-11 was also not detected in this vegetables. Conclusion of this study, Pediococcus acidilactici F-11 could be used as biocontrol agents in paprica and carrot.

Skrining Bakteri Asam Laktat Penghasil Bakteriosin dari Daging dan Produk Olahannya

Agritech Vol 24, No 2 (2004)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Lactic acid bacteria (LAB) which naturally occur in meat and meat products have been isolated and screened for their ability to produce bacteriocin. The objective of this research was to obtain the potential bacteriocin producer of lactic acid bacteria which could be used as food bio-preservative. Source of lactic acid bacteria used in this study were beef chicken flesh, vacuum packaged sausage and sliced meat obtained from traditional market or department store. Ten grams of each samples was put onto five different enrichment media, i.e., TGE (tryptoneglucose-yeast extract) pH 5 plus 3% NaCl; MRS (deMan Rogose Sharpe) pH 5,5; TGE broth pH 5,5; TGE buffer broth pH 5,5; and TGE broth plus Tween 80 & 1% Naazida pH 6,0, incubated for 24-71 hours to stimulate the growth of lactic acid bacteria. Different enrichment media were used to stimulate the growth of strains belong to each genus, since the nutritional and environmental requirement for optimum growth were suggested to be genera-dependent. Screening of LAB bacteriocin producer was carried out by dilution -pour plate methods (culture from each enrichment medium) followed by overlay using the indicator strains. Indicator strains used in this study were Lactobacillus plantarum NCDO 955, Pediococcus acidilactici LB-42, Leuconostoc mesenteroides LY, and Enterococcus faecalis MI. Colonies showing growth inhibition to indicator (indicated by clear zone) were isolated and purified. Isolates were then characterized based on Gram, catalase, shape and arrangement of cell, type of fermentation, effect of temperature to the growth and acid production from several carbon sources. From the primary screening (dilution - pour plate –overlay), 30 strains belong to Lactobacillus, Leuconostoc, Streptococcus and Enterococcus which suspected to produce antimicrobial substance were obtained. However, based on the confirmation lest (dUsion method), only three (3) strains were identified to produce bacteriocin. i. e. Leuconostoc mesenteroides SM 22, SM 32, and SM 46. In this study, Leuconostoc mesenteroides SM 22 was selected for food application. Bacteriocin of Leuconostoc mesenteroides SM-22 was able to inhibit the growth of psychrophilic bacteria naturally occur in meat and shrimp kept at refrigerator. Microbial population of raw meal with the initial number of about 3x104 CFU/g decreased one log cycle after treated with bacteriocin, and this number maintained less than 105 CFU/g after storage raw meat at refrigerator for five days. On the other side, microbial population of raw meat with no bacteriocin treatment increased to 106 CFU/g after 4 days kept at refrigerator. In the case of shrimp, washing raw shrimp with cold water could reduce the population of bacteria about one log cycle, followed treatment with bacteriocin, this populationincreased very slowly and still less than 105 CFU/g after 5 days storage at refrigerator. While without any treatment, microbial population of raw shrimp which initially about 3x105 CFU/g rapidly increased to 106 CFU/g after 3 days. This data showed that Leuconostoc mesenteroides SM-22 was a potential bacteriosin producer and can be applied as bio-preservative for cold storage fbod.

Lactic Acid Bacteria in Fermented Foods of Indonesian Origin

Agritech Vol 23, No 2 (2003)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

In this study, about 194 lactic acid bacteria strains have been isolated from 21 kinds of fermented foods (plant materials and fish origin). These fermented foods were salted-fermented fruits, vegetables & fish; fermented raw cassava (gatot & growol); tape (cassava & glutinous rice); microbial starter cultures (ragi); and fermented soybean (tempe & moromi). Among these strains, 109 belong to genus Lactobacillus, which dominated by homofermentative Lactobacillus plantarum pentosus, 25 strains belong to Pediococcus (mostly P. pentosaceus acidilactici), 45 strains Streptococcus which mostly identified as Streptococcus thermophilus, 7 strains belong to Enterococcus, which further identified as E. faecium and 8 strains Leuconostos (Weisella) as Weisella paramesenteroides. Lactobacilli have been found in all fermented foods, pediococci in 11 kind of fermented foods both plant material and fish origin, while streptococci mostly found in fermented fish, as well as enterococci and Leuconostoc. Nine strains belong to Lactobacillus plantarum - pentosus complex from different fermented food samples have been determined their DNA-DNA homology to L. plantarum NRIC 1067 and L. pentosus NRIC 1069. Result of their homology to these strains shown that all these nine strains are identified as L. plantarum. Lactic acid bacteria from Indonesian fermented foods are dominated by Lactobacillus plantarum, followed by Pediococcus pentosaceus, and Streptococcus thermophilus.

Penyiapan Starter Kering Bakteri Asam Laktat Halofilik untuk Pengolahan Hasil Perikanan Fermentatif Bergaram

Agritech Vol 22, No 2 (2002)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Lactic acid bacteria (LAB) is known as fermentation agent in traditional food fermentation products in Indonesia, which also include fish products. Objectives of this research were to select LAB strain isolated from peda, terasi, salted fish and bekasam which were potential for dry starter preparation. This research were consisted of three parts : (a) selection of halophilic LAB strain (b) dry starter preparation by addition glycerol protectant, sucrose and starter neutralization and further testing its viability upon storage and (c) ability of the selected isolate to inhibit pathogenic and spoilage bacteria. Results of this reseacrh indicated there were 8 moderate halophilic LAB, they were Lb. plantarum (isolate EDI-14, DES-21, DES-24, and DES-26), Leuc. paramesenteroides (isolate DAN-7 and DAN-7), and Lv. casei subsp. casei (isolateDES-27). Addition of 5% glycerol protects LAB viability during storage. Addition of 17.7% sucrose in the media and neutralized the pH increase LAB viability during storage. Within 5 weeks of storage. The viability of Leuc. paramesenteroides (DAN-7) and Lb. plantarum (DES-26) decrease 10.4% (from 33 x 107 sel/g to 3.3 x 107 sel/g dried starter) and 9.77% (from 36 x 107 sel/g to 3.5 x 107 sel/g dried starter), respectively. Freeze drying process and dry storage did not affect the LAB isolate towards inhibiting the pathogenic bacteria and spoilage bacteria such as Salmonella choleraesius JCM 3919, Shigella, Escherichia coli FNCC 0091, Vibrio parahaemolyticus JCM 2147 (gram negative), Staphylococcus aureus FNCC 0091, and Morganella morganii NCTC 2847 (gram positive).

Ketahanan Bakteri Psikotrofik dari Produk Perikanan Segar terhadap Bakteriosin

Agritech Vol 21, No 4 (2001)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Fresh fishery products are highly perishable and susceptible to spoilage caused by rapid growth and activity of bacteria. Psychotropic bacteria are the major microorganisms responsible for spoilage when these products stored in ice or under refrigeration. The purposes of this study were to isolate psychrotrophic bacteria from fresh fishery products and to evaluate its resistance to bacteriocins. Fresh fishery products (kembung fish, shrimp, shellfish) samples were obtained from Demangan and Kranggan traditional market. Colony count methods were used to enumerate bacteria, whereas isolation and identification of bacteria was performed by the identification method of Lahallec and Colin (1995). The identification conducted were covering Gram staining and cell morphological examintaion (cell form), motilitym presence or absence of an oxidise, mode of glucose utilization, and capacity for glucose or lactose fermentation, H2S production, and gas production. The resistance assyas by bacteriocin were carried out using agar diffusion method. Seventeen isolates were found abd they were classified as Pseudomonas, Xanthomonas, and Flavobacterium/ Cytophaga. The results show that psychrotropic bacteria resistance to supernatant of lactic acid bacteria and nisin.

Aspergillus Proteolitik Indigenous dari Koji dan Kemampuannya Mendegradasi Aflatoksin B1

Agritech Vol 24, No 3 (2004)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Legume and cereals are always exposed to the danger of fungal contamination. Among such fungi, some species of the genus Aspergillus are potential of aflatoxins producer. Aflatoxin BI (AFB1) which is the most carcinogenic mycotoxins , known very stable under cooking condition and other processing factors. The removal of AFB1 by degradation or detoxification is critical to reduce risk to human health. Microbiological degradation is a promising method for AFB1 degradation compared to others. The aim of this research was to isolate the proteolytic Aspergillus strain from "koji" and to determine its ability to degrade AFB). Out of 18 strains of Aspergillus, 16 strains were found proteolytic and only 5 strains had no afiatoxigenic properties, but all of them were able to degrade AFB1. There were no spesific pattern of the rate of AFBI degradation. Strain of KKB4 was identified as Aspergillus oryzae, that possess the highest ability to degrade AFB1. Two kind of substances were formed after degradation which were more polar than AFB1. The rate of AFB) uptake by Aspergillus oryzae KKB4 was similar with that of mycelia! growth. Aflatoxin BI inhibits mycelium growth, vesicle and conidial head formation.

Produksi Asam Asetat oleh Sel Acetobacter pasteurianus INT-7 Amobil pada Variasi Konsentrasi Etanol

Agritech Vol 24, No 2 (2004)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Acetic acid fermentation by Acetobacter pasteurianus 1NT-7 immobilized cells with alginate gel on various ethanol concentration was investigated. Immobilized acetic acid bacteria cells were prepared with alginate gel 3% concentration with ratio cell suspension and alginat gel 1:3 (v/v) and conditioning time 24 hours. Fermentation using 10% immobilized cells (beads), medium of fermentation is YEPE (yeast extract pepton ethanol) with three ethanol concentration 5%, 7,5% and 10% respectively. Fermentation is going on shaker incubator with condition 100 rpm, 30" C for 10 days. The acetic acid production, pH and cells number were monitored for evey day. The immobilized cell fermentation was compared with free cells fermentation. The yield of free cells fermentation on 5% ethanol concentration is higher (84,6%) than immobilized cells yield (64,25 %), but on 7,5% and 10% ethanol concentration the immobilised cells yield is higher (62,77% and 45,44% respectively) than free cells yield ( 61,23% and 2,54% respectively).So the acetic acid fermentation using immobilized cells is effective on 7,5% ethanol concentration, while fermentation using free cells is effective on 5% ethanol concentration

Isolasi dan Seleksi Lactobacillus yang Berpotensi sebagai Agensia Probiotik

Agritech Vol 23, No 2 (2003)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Lactic acid bacteria are important in food fermentation, in producing antimicrobial substances responsible for food preservation, and in balancing the microflora composition in gastrointestinal tract which contributing many healthful benefits (as probiotic agent). Disturbance due to pathogenic bacteria colonization in intestine as well as sterilisation of intestine due to antibiotic ingestion can be overcome by consumption of probiotic lactic acid bacteria. The objective of this study was to isolate Lactobacillus which potential for probiotic agent from intestinal material of healthy infant baby. Isolation was conducted using peptone glucose yeast extract media added with 0,2 % oxgall at pH 5, followed by incubation at 37 0C for 48 hr. Identifications were carried out based on Grain, morphological, biochemical and physiological characters, peptidoglycan types and protein profile on SDS-PAGE. Selection of probiotic agents were on based their antagonisms toward pathogenic bacteria, their resistance to antibiotics, and their survival at different oxygen availabilities. Based on morphological, biochemical and physiological characters among 12 lactobacilli strains obtained during isolation, 8 of them were identified as Lactobacillus acidophilus and the rest as Lactobacillus reuteri. However based on protein profile, L. acidophilus group has two different profiles, the first, consist of 7 strains and the second, consists of one strain. All isolates inhibited the growth of pathogenic bacteria including Shigella sp., Escherichia coli sp., Escherichia coli FNCC 009 I, Proleus sp., Salmonella choleraesius JCM 3919, Staphylococcus aureus FNCC 0047, Vibrio parahaemoliticus JCM 2147, Bacillus cereus ATCC 0057 and Listeria monocytogenes ATCC 7644, as shown by the inhibition zone ranging from 0,5-8 mm. Eight isolates of L. acidophilus were not resistant to antibiotics tested, while 3 isolates of L. reuteri were not resistant to chloramphenicol, rifampin and ampicillin, however they were resistant to tetracycline and elkosin. At reduced oxygen and anaerobic conditions all the isolates grew well, but at aerobic condition the growth was relatively slow. Strains of Lactobacillus acidophilus could be used for probiotic agents.

Cemaran Aflatoksin pada Produksi Jagung di Daerah Jawa Timur

Agritech Vol 23, No 4 (2003)
Publisher : Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia

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Abstract

Penelitian ini ditujuan untuk mengindentifikasi tingkat cemaran aflatoksin pada produksi jagung di Propinsi Jawa Timur =la, dart lingkat petani, pengecer maupun pedagang sena mendapatkan data tentang praktek pasca-panen melalui kuesioner maul, 1111 peninjauan lapangan. Pemantauan dilakukan di 4 (empat) kabupaten penghasil jagung terbesar di Propinsi Jawa Thrum yaitu Malang, Tuban, Kediri dan Senep. Uji infeksi jamur menunjukkan bahwa hampir 100% biji yang diambil balk dart petani. pengumpul maupun pedagang di empat kabupaten terinfeksi oleh jaunt)• bermiselia putih dan hitam (tidak dilakukan identifikasi lanjut), Aspergillus dan Penicillium. Kadar air jagung yang diuji berkisar antara 12.60% - 20.84%. Hal ini merupakan indikator bahwa proses pasca panen belum berlangsung dengan baik. Data uji infeksi jamur aflatoksigenik menggunakan media AFPA menunjukkan bahwa sampel dengan cemaran aflatoksin tinggi (>100 ppb), rata-rata terinfeksi dengan jamur aflatoksigenik >50 %. Hasil uji aflatoksin menunjukkan bahwa dart 115 sampel yang diambil dart petani, pengumpul dan pedagang. 27 sampel (23%) tidak terdeteksi aflatoksin, sedang 48 sampel (42%) dengan cemaran aflatoksin < 20 ppb, 26 sampel (23%) dengan cemaran 20 - 100 ppb, dan 14 sampel (12%) dengan cemaran > 100 ppb. Dart hash uji diperoleh bahwa 6 sampel memiliki cemaran aflatoksin > 300 ppb, dengan cemaran tertinggi adalah sekitar 350 ppb. Secara urnum dapat disimpulkan bahwa praktek produksi jagung yang kurang balk dapat memberi peluang terhadap tingginya cemaran aflatoksin. Rekomendasi cara bercocok tanam yang tepat, pengeringan hingga kadar air 13% yang tidak boleti ditunda, penyimpanan pada ruang yang. kering dan bersih perlu disampaikan untuk petani, pengecer dan pedagang, maupun penterintah. Demikian pula insentif bagi petani, pengumpul dan pedagang yang mampu mempertahankan kebersihan bpi dart infeksi jamur Aspergillus flavus dan cemaran aflatoksin perlu ditingkatkan.