Ethylene oxide gas is an agent in the sterilization of medical devices due to its effectiveness and compatibility with most materials. The advantages and disadvantages, as well as its recommended uses, are explored in this review article. The variables and their relevance on process optimization are described, the types of processing cycles are detailed and emphasis is given to the design and validation of the sterilization process.
A study on bioremediation of soil contaminated with petroleum sludge was performed using Bacillus pumilus/MVSV3 (Accession number JN089707). In this study, 5 kg of agricultural soil was mixed well with 5% oil sludge and fertilizers containing nitrogen, phosphorus and potassium (N:P:K). The treatment resulted in 97% removal of total petroleum hydrocarbon (TPH) in 122 d in bacteria mixed contaminated soil when compared to 12% removal of TPH in uninoculated contaminated soil. The population of the microorganism remained stable after introduced into the oil environment. The physical and chemical parameters of the soil mixed with sludge showed variation indicating improvement and the pH level decreased during the experiment period. Elemental analysis and Gas Chromatography-Mass Spectroscopy (GC-MS) analysis revealed the bacterial ability to degrade oil sludge components. Growth experiments with Trigonellafoenumgraecum (Fenugreek) showed the applicability of bioremediated soil for the production.
The kinetics of the inactivation of Vibrio parahaemolyticus in sodium chlorite (NaClO2) solution was studied in the weakly acidic pH range of 4.0 to 6.5 and at various temperatures. The logarithmic reduction of the survival ratio depended on the concentration-time product, and all the inactivation curves showed a linear reduction phase. The first-order inactivation rate constant (k) increased by approximately twice for every 0.44 unit fall in pH. During the inactivation experiments, no formation of chlorine dioxide occurred. These data indicated that undissociated HClO2 was the active species governing the inactivation of V. parahaemolyticus. It was also shown that the use of weakly acidic NaClO2 solutions containing high concentrations of ionized ClO2- gave slower kinetics of the inactivation, whereas it could achieve the significant reduction of viable cells of more than 4-log. The k value showed an Arrhenius-type temperature dependence in the temperature range of 5 to 40℃. The apparent activation energy for the inactivation of V. parahaemolyticus was estimated to be 43.5 kJ/mol. The k value increased by approximately 1.8 times for every 10℃ rise in temperature.
The antiaflatoxigenic and antifungal activities of essential oils (EOs) of finger root (Boesenbergia rotunda (L.) Mansf.), pine (Pinus pinaster), rosewood (Aniba rosaedora), Siam benzoin (Styrax tonkinensis), Thai moringa (Moringa oleifera), and ylang ylang (Cananga odorata) were tested for Aspergillus parasiticus and Aspergillus flavus in potato dextrose broth. Aflatoxin B1 (AFB1) was extracted from culture using a QuEChERS-based extraction procedure and analyzed with high performance liquid chromatography (HPLC) coupled to a fluorescence detector. EO of pine showed the greatest inhibition of growth and AFB1 production of A. parasiticus, followed by EOs of rosewood, finger root, Siam benzoin, and ylang ylang. EO of finger root gave the best inhibitory effects on A. flavus, followed by EOs of rosewood, pine, ylang ylang, and Siam benzoin. EO of Thai moringa did not show any significant inhibition of aflatoxigenic fungi. The antiaflatoxigenic activities of EOs correlated with their antifungal activities in the dosedependent manner. Comparison of the application of the five selected EOs in peanut pods by direct and vapor exposure indicated that the AFB1 production inhibitory effects of the five EOs by direct exposure were faster and more effective than by vapor exposure. EO of finger root showed the best inhibition of AFB1 production of A. flavus in peanut pods by direct exposure, followed by EOs of pine, rosewood, ylang ylang, and Siam benzoin.
The objective of this study was to determine the contamination of aflatoxin B1 (AF-B1) when keeping various dairy feeds in a farm environment. The study was carried out from March to May 2011 and involved 63 small holder dairy farms belonging to a single dairy cooperative in Chiang Mai province, Thailand. All feed samples used for milking cows including 4 commercial concentrates (CC1 to CC4), by-products from local corn processing factories fermented in plastic bags (SIL), and corn and cob meal or corn dust (CCD). Feed samples were collected 2 times at before and after storage. Farmers were requested to store CC1 to CC4 and CCD for a month and SIL for a week using their routine on-farm storage arrangements. All samples were measured for their AF-B1 concentrations by ELISA. Results showed that AF-B1 concentrations of CC1 to CC4, SIL and CCD before storage were 5.1, 4.1, 4.0, 4.2, 5.5 and 5.5 μg/kg, respectively, and after storage the concentration of AF-B1 were 9.7, 6.5, 9.8, 12.3, 11.4 and 20.0 μg/kg, respectively. CCD at after storage was the only feed that had mean level more than 20 μg/kg. Concentrations of AF- B1 at before storage in all feeds were significantly lower than after storage (P<0.01), and the increased ratio of AF-B1 levels was approximately 2 to 3 times. The study concluded that increased AF-B1 levels are related to feed types and farm conditions.
Quantitative antifungal testing methods for textile fabrics under growth-supportive conditions were studied. Fungal growth activities on unfinished textile fabrics and textile fabrics modified with Ag nanoparticles were investigated using the colony counting method and the luminescence method. Morphological changes of the fungi during incubation were investigated by microscopic observation. Comparison of the results indicated that the fungal growth activity values obtained with the colony counting method depended on the morphological state of the fungi on textile fabrics, whereas those obtained with the luminescence method did not. Our findings indicated that unique characteristics of each testing method must be taken into account for the proper evaluation of antifungal activity.
The present study surveyed the occurrence of Cronobacter spp. in dried foods including milk powder, spices and herbs and others, and fresh vegetables commercially available in markets, and ground soil materials for the agriculture. Cronobacter spp. were isolated from 15% of 33 spice and herb samples and 3% of 36 taste foods, and these were C. turicensis, C. malonaticus, C. sakazakii and C. dubliensis. Cronobacter spp. from fresh vegetables were detected in 12% of field vegetables and 13% of hydroponic vegetables. C. turicensis was prevalent in field vegetables, and C. malonaticus was in hydroponic ones. And, Cronobacter spp. in shredded vegetables were detected from 44% of 9 samples, and these were C. dubliensis, C. turicensis and C. sakazakii. Also, Cronobacter spp. in soil from rice field, vegetable field and sandpits were predominantly C. sakazakii and C. malonaticus.
Aquatic bacteria were isolated from the hands of working staffs by an adapted culture protocol. When the sample solution obtained by the“ glove juice method” was incubated for 3 days at room temperature, viable cell counts increased up to 105-fold, and the majority of the isolated colonies were shown to be Gram-negative aquatic bacteria, which carry the risk of contaminating water. Using R2A medium, coagulase-negative staphylococci were the dominant microbes immediately after recovery from the hands. Here it was revealed that bacteria of the phylum Proteobacteria isolated from the hand can be the causative bacteria of aqueous contamination. This modification in the GJ method may be useful as an effective training protocol to demonstrate the importance of hand hygiene and clean operation for aseptic manufacturing.
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