Open Access Minireview Article

A Brief Review of Oyster-associated Microbiota

Zhen Li, Verona V. Nicolae, Raji Akileh, Tuoen Liu

Microbiology Research Journal International, Page 1-14
DOI: 10.9734/MRJI/2017/33842

Oysters are important mariculture species worldwide. Because of their filter-feeding behaviors, oysters contain complicated microbial populations, and these varying microbial populations can provide a correlation to increased oyster mortalities in the oyster farming industry as well as food outbreaks associated with public health surveillance. This review summarizes the significant outcomes in oyster microbiota research, including the identified oyster-associated bacterial taxa and comparison of different oyster tissues for microbial studies. In addition, environmental factors that could potentially affect the dynamics of oyster microbiota are discussed. Recent approaches developed to study oyster microbiota as well as their limitations are also highlighted in this review. Finally, future directions in oyster microbiota research have been suggested.

Open Access Original Research Article

Effect of Modified Atmosphere Packaging and Multilayer Flexible Films on pH of Fresh Quail Meat

Nazanin Zand, Sharare Jabbari

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/MRJI/2017/29564

Aim: In this study, the effect of different concentrations of three gas mixture (Carbon dioxide, Nitrogen, Oxygen), and also vacuum and ordinary conditions and using different flexible multi-layer pouches were studied for evaluating pH changes of quail meat at (4°C).

Methodology: Ordinary conditions (control conditions) were compared with four types of modified atmosphere packaging: (N270%+ CO230%), (N230% + CO270%), (45%CO2+45%N2+10%O2), and vacuum conditions. Samples of quail meat were packaged in flexible multilayer pouches under modified atmosphere packaging, 3-layer (PET(12)/AL(12)/LLD(100)), 4-layer (PET(12)/AL(7)/PET(12)/LLD(100)), and 3-layer ( PET(12)/AL(7)/LLD(100)), in different times during 16 days, with 15 treatment, 3 run. Statistical analysis and comparison of data, were done by software SPSS (Ver: 22) and Duncan’s new multiple range test, with confidence level of 95% (P <0.05).

Results: Packed samples were performed chemical test (pH test). The changes of pH in fresh samples were not acceptable under % 30 CO2 and also vacuum conditions in these containers. However, the best conditions belonged to CO2 70%, and then CO2 45%, that were acceptable. Packed samples in 4-layer under gas combination CO2 70% had best results.

Conclusion: Protection­ of these meats in 4-layer container was better than 3-layer container because the steam permeability of 4-layer was lower than 3-layer and also increasing CO2 could not adversely effect on pH ,and postponed the pH changes and preserving quail meat till 16 days.

Open Access Original Research Article

Effects of Water Treatment Methods on Protein Profile of Escherichia coli O157:H7 and Escherichia coli Non-O157 Isolated from Drinking Water Sources in Ado-Ekiti, Ekiti State, Nigeria

Busayo M. Olowe, Jacob O. Oluyege, Oladiran Famurewa, Titilayo O. Femi-Ola, Adebayo O. Osesusi, Catherine O. Edward

Microbiology Research Journal International, Page 1-10
DOI: 10.9734/MRJI/2017/33638

Aim: To examine the effects of water treatment methods on the protein profile of Escherichia coli O157 and Escherichia coli non-O157 isolated from different drinking water sources in Ado-Ekiti.

Study Design:  Experimental study design.

Place and Duration of Study: Department of Microbiology, Ekiti State University, Ado-Ekiti, Nigeria, between December 2015 and June 2016.

Methodology: The test organisms, E. coli O157 and E. coli non-O157, were charged against some water treatment methods such as silver nitrate, sunlight, low and high temperature and varied pH using standard methods. Protein expression profiles of these organisms, before and after exposure, were studied with cell crude proteins extract using standard SDS-PAGE method. Statistical analysis was carried out on the data generated using correlation matrix.

Results: The survivability testing showed that E. coli O157 survived better than E. coli non-O157. Silver nitrate, among all other agents used, exhibited the most lethal effect on both serotypes. The protein profile of the two serotypes was similar before their exposure (r = 0.9897, P-value = 0.941), while after their exposure, they exhibited different characteristic responses (r = 0.693, P-value = 0.018).

Conclusion: This study showed that the treatment methods had effects on the expression of bacterial protein profile following exposure.

Open Access Original Research Article

Effect of Fermentation on Nutrient and Antinutrient Contents of Fermented Whole and Ground African Breadfruit (Treculia africana) Seeds

K. T. Adegbehingbe, S. Fakoya, B. S. Adeleke

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/MRJI/2017/34444

Aim: This study investigated the microbial contents, proximate compositions and the antinutrient contents of whole and ground fermented African breadfruit seeds.

Methodology: The whole and ground samples were fermented for 72 hours. The microbial contents, pH, total titratable acidity and temperature of the samples were monitored on daily basis while their proximate composition and antinutrient contents were determined before and after fermentation.

Results: Total microbial counts increased in both samples but higher in fermented ground samples. The microorganisms isolated were Bacillus (B.) subtilis, B. pumulis, Staphylococcus (S.) aureus, Lactobacillus (L.) plantarum, L. bulgaricus, Leuconostoc (L.) mesenteroides, Aspergillus (A.) niger, A. flavus and Saccharomyces (S.) cerevisiae. B. subtilis and L. plantarum were isolated from both samples throughout the fermentation period. The pH of the fermented ground samples decreased from 6.53 to 5.25 while the fermented whole samples decreased from 6.42 to 5.73. The TTA of ground and whole samples increased from 2.34% to 3.60% and from 2.43% to 3.12% respectively. The temperature of the ground sample increased from 27.6°C to 30.8°C while the whole sample increased from 27.8°C to 31.2°C. The crude protein contents of the fermented ground and whole samples increased from 18.40% to 25.71% and 24.39% while crude fat contents reduced from 5.45% to 2.61 and 3.47% respectively. The crude ash contents had higher content in fermented ground sample (3.13%) than fermented whole sample (2.13%) while fibre contents significantly reduced from 2.66% to 1.46% and 1.87% and carbohydrate contents from 61.53% to 54.87% and 55.63% respectively. All the antinutrient contents significantly reduced in both fermented samples with more reductions in ground sample. The fermented ground sample had highest overall acceptability than the whole sample and the raw sample. 

Conclusion: Improvement in the nutritional content and reduction in the antinutrient contents of the fermented samples suggest their usefulness as supplements in food and feed formulation for human and livestock.

Open Access Original Research Article

Potential Public Health Risks of Pathogenic Bacteria Contaminating Marine Fish in Value Chain in Zanzibar, Tanzania

A. R. Rabia, P. N. Wambura, S. I. Kimera, R. H Mdegela, A. Mzula

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/MRJI/2017/34030

Aims: Marine sourced food, to a large extent, provides protein and nutrients to people of Zanzibar where 85% of Zanzibar population consume fish at least five times a week. This study was carried out to investigate the safety of marine foods consumed in Zanzibar.

Study Design: A longitudinal study design was used to investigate variations in colony forming units along the value chain of fishermen, vendors and consumers. A cross sectional study design was used to study the profile and number of microbial pathogens. A repeated cross sectional study was used for value chain analysis.

Place and Duration of Study: The study was carried out in Zanzibar, Tanzania between August 2014 and June 2015.

Methodology: A total of seven hundred and eighty fish samples were collected seasonally through the value chain from fishermen, through vendors to ready-to-eat food (consumer), between 2014 and 2015 with the aim of assessing bacterial contamination (colony forming units (CFUs), identify prevalent bacterial species and investigate if the pattern of CFUs is influenced by ambient temperatures, rainfall or human activities. The study was also intended to investigate antibiotic sensitivity profile of some of the prevalent bacteria. Sample collection was done from 8 different landing sites. Moreover, an additional 60 samples were collected from one recreation site.

Results: It was observed that bacterial load tended to increase in January-March season when ambient temperatures were high and fell down during the cool season July-September even though the difference was not statistically significant (p>0.05). Bacterial loads were higher in fish collected from vendors than in fishermen or consumers, again the difference was not significant (p>0.05). Bacterial load of fish from consumers in a recreation site (Forodhani) were highly significant (p<0.0001) compared with the rest of the counts in the value chain. There was no evidence that anthropogenic activities like tourism affected bacterial load. However, fish collected from town based landing sites tended to have higher bacterial loads which could be attributed to sewage disposal and human activities. Thirty one bacterial species were identified and many of them were of public health importance. Antibiotic disc sensitivity tests revealed existence of multidrug resistance among 21% of Staphylococcus aureus isolates.

Conclusion: To improve the hygiene situation food safety rules must be enforced, food tracing system must be strengthened and mass awareness for improvement of hygiene standards be implemented to all fish stakeholders.