فهرست مطالب

  • Volume:6 Issue: 1, 2020
  • تاریخ انتشار: 1398/12/11
  • تعداد عناوین: 8
|
  • Lieu My Dong*, Le Thi Hanh Quyen, Truong Duc Thang, Dang Thi Kim Thuy Pages 1-5
    Background

    The present study aimed to investigate the effects of various encapsulation methods on Lactobacillus acidophilus viability using wall materials variably.

    Methods

    L. acidophilus was encapsulated using the extrusion and emulsion encapsulation methods with calcium-alginate and skim milk via mixing or coating. The particle size, encapsulation yield, and viability of L. acidophilus in the simulated gastric and intestinal fluids were investigated.

    Results

    The mean particle size in the emulsion and extrusion methods was within the range of 161 µm to1.95 mm, and the coated samples were smaller than the mixed samples. The encapsulation yield of the extrusion method was higher compared to the emulsion method. In addition, skim milk was essential to improving the L. acidophilus viability, which significantly improved in the calcium-alginate particles coated by skim milk compared to the mixed samples.

    Conclusion

    According to the results, the coating process by skim milk not only improved probiotic viability, but it also reduced the preparations particle size, which in turn decreased the adverse effects of the preparations on the sensory properties of food.

    Keywords: Emulsion, Encapsulation, Extrusion, Lactobacillus acidophilus, Skim milk
  • Ayodele Owolabi*, Patrick Adesida Pages 6-10
    Background

    Blasting is used for the extraction of hard rocks using explosives and has easy operation and high efficiency. The explosives used in blasting are combined chemical substances, which enter the environment after detonation. This study aimed to investigate the effects of the chemicals released into the environment in blasting.

    Methods

    Water and soil were collected from inside and outside the quarry. Heavy metals and other deleterious constituents were assessed for AAS, and the results were compared with the WHO standards (domestic water use) and FAO (classification of soil macro- and micronutrients). The impact of mining on water and soil was evaluated by comparing the samples of the inside/outside the quarry.

    Results

    The mean pH of the water samples of the inside and outside the quarry was 5.52 and 5.47, respectively. Manganese and chromium in both water samples were WHO standard, while lead and cadmium were not detected in these samples. The mean pH of the soil samples of the inside and outside was 5.98 and 6.0, respectively. The heavy metals in the soil samples were FAO standard.

    Conclusion

    Quarrying adversely affects the environment. The EIA and strict implementation of the outlined mitigation measures should be enforced to guarantee sustainability.

    Keywords: Blasting, Explosives, Heavy metals, Environmental impact
  • Maryam Shamsi, Abbasali Zamani*, Younes Khosravi, Abdolhossein Parizanganeh, Zahra Shamsi Pages 11-18
    Background

    Focus on environmental heavy metals is important due to their adverse impact on the human health and environment. This study aimed to determine the lead and nickel concentrations and their spatial patterns in the street dust of Zanjan city, Iran, which is enclosed with metal production (especially lead and zinc industries).

    Methods

    Fifty urban street dust samples were collected from Zanjan and analyzed for lead and nickel after Aqua Regia digestion via flame atomic-absorption spectrophotometry. The sediment contamination degree and origin of the pollutants were assessed using the geo-accumulation index. Pollution status was assessed using the enrichment factor and potential ecological risk index (Hakanson index).

    Results

    The mean, minimum, and maximum lead were 745, 30, and 4610 mg/kg and 72, 32, and 154 mg/kg for nickel, respectively. The mean lead concentration was higher than the local background value. The element spatial distribution showed higher lead concentration in the east, west, and southwest, main streets, and Qazvin-Tabriz highways. Higher potential ecological risk was observed for lead, confirming regional pollution.

    Conclusion

    High lead concentrations could be attributed to vehicle emissions and industrial activities (lead and zinc companies in Zanjan). Traffic and frequent braking of vehicles could increase nickel concentrations.


    Keywords: Pollution, Spatial analysis, Heavy metal, ArcGIS
  • Hassan Izanloo, Zahra Atafar, Yadollah Ghafuri* Pages 19-23
    Background

    The water safety plan is the new approach of the WHO to ensuring the quality and safety of drinking water. This study aimed to investigate the microbiological quality control accreditation process in the identification and risk assessment of the critical points in the water safety plan of Qom province, Iran.

    Methods

    This descriptive study was conducted in two phases; initially, the microbial indicators of microbial validation were monitored (fecal streptococci, heterotrophic plate count, Escherichia coli, and bacterial ratio). The other qualitative and chemical parameters of water in the distribution network were also assessed (pH, residual chlorine, temperature, and turbidity). The DotMapper software was used to identify the critical control points. The second phase involved risk assessment and critical control point design.

    Results

    We selected 160 urban water distribution network points. In 30 points, the critical points were determined based on the fecal contamination indicators using the DotMapper software. Based on the risk assessment model and semi-quantitative method, the urban water distribution network was considered high-risk.

    Conclusion

    Considering the implementation steps of the water safety program in urban water distribution networks, attention must be paid to validating microbial indicators and the impact on identifying critical control points and control criteria.

    Keywords: Water, Safety, Risk, Qom
  • Mahdieh Momayyezi, Hossein Fallahzadeh*, Zohreh Rahaei, Fatemeh Akrami, Mahdieh Hosseini, Shokufeh Shakhs Pages 24-29
    Background

    Proper food management during food preparation and maintenance is essential to reducing foodborne diseases. The theory of planned behavior (TPB) is commonly used for the examination of health behaviors. No research has assessed the effectiveness of TPB in predicting food safety behaviors in Iran. The present study aimed to examine food safety behaviors based on the TPB.

    Methods

    This cross-sectional study was conducted on 220 women in Yazd, Iran in 2018. Data were collected using a researcher-made questionnaire consisting of items on food safety behaviors and TPB constructs with confirmed reliability and validity. Data analysis was performed in SPSS version 21.0.

    Results

    A significant, positive correlation was observed between food safety behaviors and all the TPB constructs (r = 0.15- 0.38; P < 0.05). In addition, intention was significantly correlated with food safety behaviors (r = 0.35; P < 0.001), and 27% of the behavior variance was explained by the TPB constructs. Perceived behavioral control was the strongest predictor (β = 0.3; P < 0.001), and 31% of the intention variance was explained by the TPB constructs. Subjective norm was considered the strongest predictor (β = 0.41; P < 0.001).

    Conclusion

    The TPB could be used as a framework for the educational interventions aimed at health observance in food preparation.

    Keywords: Food safety, Behavior, Theory of planned behavior
  • Batool Soltaninezhad, Saeid Khanzadi*, Mohammad Hashemi, Mohammad Azizzadeh Pages 30-34
    Background

    Antimicrobial compounds have numerous applications, and essential oils could be used in edible films to enhance the food shelf life. This study aimed to assess the inhibitory effects of a chitosan/cellulose nanofiber (CNF) film containing the nanoemulsions of Bunium persicum essential oil (NBPEO) and Trachyspermum ammi essential oil (NTEO) on Escherichia coli O157:H7 inoculated in hamburger during storage  (4°C).

    Methods

    After inoculation, the hamburger samples were classified into three treatment groups of, control, chitosan containing 7.5% CNF (Ch-CNF), and chitosan containing 7.5% CNF enriched with 1.6% NTEO and 0.8% NBPEO (Ch-CNF-NEO). The samples were preserved at the temperature of 4°C, and the bacterial counts were determined on days zero, three, six, nine, and 12. Data analysis was performed using Bonferroni post-hoc test and repeated measures ANOVA.        

    Results

    The mean E.coli O157:H7 count significantly decreased in the treatments groups compared to the control group. In addition the Ch-CNF-NEO film exerted the most significant inhibitory effects on the growth of E. coli O157: H7 in the hamburger samples.

    Conclusion

    According to the results, the Ch-CNF-NEO film could effectively reduce the growth of E. coli O157:H7 in hamburger. Therefore, Ch-CNF-NEO film could be used to effectively increase the safety of meat products against E. coli O157: H7.

    Keywords: Trachyspermum ammi, Bunium persicum, Chitosan, Escherichia coli O157:H7, Nanoemulsion
  • Mansour Rezazadehazari, Fatemeh Sahatfardi*, Fatemeh Zarei, Sosan Salehpour, Hamid Soori, Mohammad Ranjbarian Pages 35-39
    Background

    Brick manufacturing produces dust, occupationally exposing workers to hazardous substances (e.g., silica dust). Iran is a ceramic exporter. Few studies have assessed the exposure of workers to silica dust. This study investigated occupational exposure to crystalline silica dust, total respiratory dust, and spirometry performance in traditional and mechanical brick factories.

    Methods

    This cross-sectional study involved 70 workers in two brick factories (case) and 70 workers in a food industry (control) in 2016, who were monitored for crystalline silica and respirable dust exposure (NIOSH No.7602 and No.600). The exposure of 40 workers in the mechanical brick factory and 30 workers in the traditional brick factory to respirable crystalline silica and dust was compared with the controls. Data were analyzed using SPSS version 19.

    Results

    The mean respirable crystalline silica and general dust exposure in the mechanical and traditional brick factories was 0.47, 18.43, 0.651, and 28.27 mg/m3, respectively. The cases (brick factory) had lower FEV1%, FVC%, FEV1/FVC%, and PEF% indices compared to the controls.

    Conclusion

    The mean substance exposure was above the occupational limits. The pulmonary capacities in the traditional and mechanical brick factories had no significant difference. However, the pulmonary function capacities were significantly lower than the controls.

    Keywords: Brick factory, Occupational exposure, Crystalline silica, Respirable dust, Lung function tests
  • Mahdi Maleki Kakelar*, Mohsen Yavari, Mohammad Reza Yousefi, Amir Nimtaj Pages 40-46
    Background

    Microbial induced carbonate precipitation (MICP) is a promising biological soil improvement method in geotechnical and geo-environmental engineering, which requires the recognition of the effects of various treatment methods on its applications.

    Methods

    To improve the efficiency of MICP by urea hydrolysis bacteria, bio-grouting experiments were conducted at low urease activity using laboratory sand columns, and injection scenarios with different procedure steps were performed. The scenarios varied in the incubation time, fixation fluid, and number of the injection steps, and their efficiency was assessed using the unconfined compressive strength test.

    Results

    The sand column experiments with multistep injection of bacteria and cementation solution showed that when the precipitated calcium carbonate content increased from 7.7% to 18.9%, the strength of the samples enhanced from 0.25 to 1.55 MPa, respectively. The precipitation conditions were influenced by the sand grain properties. The samples with diversified particle sizes had greater strength than those with uniform particle sizes. The multistep cementation solution injection at various concentrations had a significant clogging effect, thereby decreasing the sand column permeability.

    Conclusion

    According to the laboratory results, this innovative technique could be potentially practical for engineering applications, such as liquefaction prevention, clogging, and sand in oil reservoir consolidation.

    Keywords: Soil consolidation, Microbial induced carbonate precipitation, Urease, Injection procedure, Clogging