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Volume 1 Issue 1

Published May 2011

Articles in this issue

  • Using Mortality Compost in Vegetable Production: A comparison between summer and winter composting and its use in cabbage production

    Published 05/2011

    volume 1 issue 1
    Pp. 6-14

    Keywords: , , ,

    Abstract:

    A study was conducted to determine the effectiveness of composting to breakdown the carcasses of daily poultry mortality and in the process destroy pathogenic microorganisms that may be present. The study was conducted during the summer and repeated in the winter to determine whether the time of year would affect the temperature profile or the length of time required for the process to be completed. Daily mortalities were collected from a nearby producer and layered in a compost bin each day for four days. Samples were collected from the litter before it was placed in the bin. Compost samples were collected every other day for a week after the bin was compiled and then once per week until the process was completed. The samples were evaluated for microbial content. Temperature was taken and recorded at random points in the bins on a daily basis. Upon completion of the composting process, the material was used as a soil amendment in two vegetable plots while a third plot without compost material served as the control. Soil samples were collected from each of the plots prior to application of the compost material. Cabbage seedlings were then planted in each of the plots. Vegetative samples and soil samples were collected and evaluated for microbial presence prior to planting and at week, 1, 3, 7, and again at reaping. The summer compost had the highest temperature of 156°F on d 9 during the primary phase while the winter compost had the highest temperature of 156°F on d 42 during the secondary phase of the compost. The summer compost samples were Salmonella enterica (SE) negative from d 2 of the trial but mixed bacterial colonies remained for the duration of the study. The vegetative samples in plot 1 had coliform levels of 3.48 log10/gm at wk10 but the levels was not considered significantly different from the other two plots (p<0.05). The results show that while winter composting can effectively breakdown poultry carcasses and attain high temperatures, summer compost is more efficient and had consistently higher temperatures.

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  • Determination of antifungal activity of Pseudomonas sp. A3 against Fusarium oxysporum by high performance liquid chromatography (HPLC)

    Published 05/2011

    volume 1 issue 1
    Pp. 15-23

    Keywords: , , , , , , ,

    Abstract:

    It has frequently been reported that chitinolytic soil bacteria, in particular biocontrol strains, can lyse viable fungal hyphae and thereby release potential substrates for bacterial growth. The present work was carried out with an objective to get a better understanding of the relationship between chitinolytic and antifungal properties of bacteria that occur naturally in coastal soils, i.e. without artificial selection. Among the bacterial, strain A3 was identified as Pseudomonas sp. A3 based on morphologic observation and 16S rRNA analysis. Strain A3 exhibited a maximum chitinase production of 1.44 U/ml in CC broth after 3 days of cultivation. Besides having chitinolytic activity, the molecular weight of the crude enzyme was estimated to be 56 kDa by SDS-PAGE and zymogram. In vitro assays revealed that the crude chitinase inhibited activity of Fusarium oxysporum as identified by dual plate assay and microscopic methods. Hydrolysis products of the fungal cell wall by the crude enzymes of Pseudomonas sp. A3 were analyzed by high-pressure liquid chromatography (HPLC) and identified as oligosaccharides, which included monomers (GlcNAc), dimers (GlcNAc)2, and trimers (GlcNAc)3 using chitin oligomer standards. The crude chitinase isolated from strain A3 can be directly applied for suppressing growth of viable fungal hyphae.

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  • Multi food functionalities of Kalmi Shak (Ipomoea aquatic) grown in Bangladesh

    Published 05/2011

    volume 1 issue 1
    Pp. 24-32

    Keywords: , , , , ,

    Abstract:

    Kalmi Shak or water spinach (Ipomoea aquatic) is a Bangladeshi indigenous green leafy vegetable and herbaceous aquatic or semi aquatic perennial plant. A primary study was conducted to elucidate the multi functionalities of this vegetable. Extract of Kalmi Shak exhibited high antioxidant properties with hydrophilic-oxygen radical absorbance capacity (H-ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity being 341.92 ± 1.32 and 37.67 ± 2.63 µmol Trolox equivalent / gram of dry weight (TE/g DW), respectively. The total polyphenols content was estimated to be 12.56 ± 0.08 mg gallic acid equivalent / gram of dry weight (mg GAE/g DW), and moisture content was found to be 85%. The extract also showed anti-mutagenic effect on Trp-P2 induced mutagenicity to Salmonella Typhimurium TA98, and anti-tumor activity to mouse myeloma cell line P388. The extract of this vegetable also exhibited anti-bacterial activities against several spoilage and pathogenic bacteria. The multi functionalities, economic price and availability during the entire year have made this indigenous Bangladeshi vegetable important from both medicinal and industrial aspects.

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  • Using Hydrogen Limited Anaerobic Continuous Culture to Isolate Low Hydrogen Threshold Ruminal Acetogenic Bacteria

    Published 05/2011

    volume 1 issue 1
    Pp. 33-44

    Keywords: , , , , , , , ,

    Abstract:

    Hydrogen-limited continuous culture was used to isolate autotrophic acetogenic bacteria from rumen contents of cattle on either a high roughage or a high concentrate diet. Twenty bacterial isolates were ob- tained and were presumptively identified as acetogenic bacteria. They were able to use H2:CO2 and they produced acetic acid as their sole end-product. Two isolates were selected for further studies based upon their low hydrogen threshold values. The acetogenic strain H3HH was a strictly anaerobic gram positive coccus with a hydrogen threshold of 1390 ppm. The acetogenic strain Al0 was a facultatively anaerobic gram positive coccus with a hydrogen threshold of 209 ppm. The use of H2 limited continuous culture to isolate low H2 threshold ruminal acetogens suggests that not only do acetogens with these properties exist in the rumen but this approach could be used in other ecosystems as well.

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  • Effect of Plant-based Protein Meal Use in Poultry Feed on Colonization and Shedding of Salmonella Heidelberg in Broiler Birds

    Published 05/2011

    volume 1 issue 1
    Pp. 45-53

    Keywords: , , , , , , , ,

    Abstract:

    The objective of this experiment was to determine the effect of plant-based protein meals (soybean and canola) in poultry feed on colonization and shedding of Salmonella Heidelberg in broiler birds over a 42- day period. One-day old chicks were randomly assigned to 4 different dietary treatments (n=360 birds per treatment) with 6 replicates per treatment, 60 birds per replication. Three all plant protein meal diets and one commercial diet containing animal protein meal (meat and bone) were used in the study. Half of the birds (n=30) per pen were challenged with nalidixic acid-resistant (NA) S. Heidelberg on day one (called seeders), and the remaining unchallenged birds were called contacts. Drag swabs were collected from all pens on days 0 (prior to placement), 14, and 42. Ceca samples were collected from 20 birds per pen (10 seeders and 10 contacts) on day 42.Drag swabs and ceca samples were examined for NA- S. Heidelberg using enrichment and enumeration/enrichment, respectively. All drag swabs were negative on day 0, but positive for S. Heidelberg on both days 14 and 42. Within seeder and contact birds, there was no signiZ- cant differences in:1) NA-S. Heidelberg concentration (cfu/g of ceca), and 2) proportions of positive ceca among the treatment groups.It can be concluded that all plant-based protein meal diets did not signiZ- cantly reduce the environmental contamination with S. Heidelberg nor did it reduce the concentration and proportion of positive S. Heidelberg in contact and seeder birds compared to commercial diet containing animal protein meal.

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  • Optimization of Fermentative Production of Keratinase From Bacillus Subtilis NCIM 2724

    Published 05/2011

    volume 1 issue 1
    Pp. 54-65

    Keywords: , , , , ,

    Abstract:

    Microbial keratinases have become biotechnologically important since they target the hydrolysis of highly rigid, strongly cross-linked structural polypeptide “keratin” recalcitrant to the commonly known proteolytic enzymes trypsin, pepsin and papain. Keratinases are produced in a medium containing kerati- nous substrates such as feathers and hair. This paper reports on the optimization of keratinase production by Bacillus subtilis NCIM 2724. One factor-at-a-time method was used to investigate the effect of carbon sources, nitrogen sources and pH on keratinase production. An L8 orthogonal array design was adopted to select the most important fermentation parameters influencing the yield of keratinase. Response surface methodology (RSM) was used to develop a mathematical model to identify the optimum concentrations of the key parameters for higher keratinase production, and confirm its validity experimentally. The effect of various amino acids on the production of keratinase was also studied. The final optimized medium gave a maximum yield of 12.32 KU ml-1 of keratinase. Keratinases are commercially important among the proteases that have been studied since they attack the keratin residues and hence find application in developing cost-effective feather by-products for feeds and fertilizers.

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  • An Overview of Stress Response Proteomes in Listeria monocytogenes

    Published 05/2011

    volume 1 issue 1
    Pp. 66-85

    Keywords: , , , , , ,

    Abstract:

    Listeria monocytogenes adapts to diverse stress conditions including cold, osmotic, heat, acid, and alkali stresses encountered during food processing and preservation which is a serious food safety threat. In this review, we have presented the major findings on this bacterium’s stress response proteomes to date along with the different approaches used for its proteomic analysis. The key proteome findings on cold, heat shock, salt, acid, alkaline and HHP stresses illustrate that the cellular stress responses in this organism are a culmination of multiple protein expression changes in response to a particular stress stimuli. Moreover, a number of key proteins may be involved in conferring the cross protective effects against various stress environments. As an example, ferritin-like protein (designated as Fri or Flp) is induced during cold, heat, and HHP stresses. Similarly, general stress protein Ctc is induced in cold and osmotic stresses while molecular chaperones such as GroEL and DnaK are induced in cold and heat stresses. Furthermore, a number of stress proteins also contribute towards L. monocytogenes virulence and pathogenicity. Future research may lead to understanding the stress proteomes of this pathogen induced on various food matrices and processing environments in which it can persist for long periods of time.

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