Microwave-assisted extraction of bioactive compounds from Sarawak Liberica sp. coffee pulp: Statistical optimization and comparison with conventional methods

Coffea liberica, commonly known as Liberica coffee, is a kind of coffee that originated in Liberia, a West African country. It is considered a less- known coffee bean vari-ety, which accounts for less than 2% of commercially produced coffee worldwide. In this study, the influences of optimization of microwave-assisted extraction (MAE) on the total phenolic content (TPC), total flavonoid content (TFC), and total carbo-hydrate content (TCC) of bioactive compounds extracted from Sarawak Liberica sp. coffee pulp were studied. Response surface methodology was adopted with a face- centered central composite design to generate 34 responses by taking three micro-wave parameters into consideration, microwave power (watt), time of irradiation (second), and solvent-to-feed ratio as independent variables. As a result, the findings revealed that optimum extraction conditions were conducted as follows: microwave power of 700 W, time of irradiation of 180 s, and solvent-to- feed ratio of 86.644:1. While under optimal extraction conditions, MAE outperformed conventional mac-eration extraction in terms of extraction efficiency and had no significant difference (p< .05) with Soxhlet extraction on the extraction of TPC (12.94 ± 2.25 mg GAE/g), TFC (9.84 ± 0.38 mg QE/g), and TCC (876.50 ± 64.15 mg GE/g). Present work advances the usage of Sarawak Liberica sp. coffee for the development of functional products and aids in reducing environmental pollution by utilization of coffee pulp waste

Time course study on the growth of Salmonella Enteritidis on raw vegetables used in sandwiches

A time course study on the growth of Salmonella Enteritidis on raw vegetables used a part of the ingredients for sandwiches at room temperature and at 4°C, with initial microbial load of log 3 and log 1 spiked onto the lettuce and cucumber slices. The growth of Salmonella Enteritidis were higher at room temperature and were dose dependent. The information obtained in this study may contribute towards food handling solutions in order to be able to control the food safety of fresh produce

The Prevalence of Vibrio cholerae and Vibrio parahaemolyticus Virulence Genes and Multiple Antibiotics Resistant (MAR) Assessment from Local Shrimp Farm in Sarawak

Excessive and improper antibiotic use in animals raised for human consumption can increase the risk of antibioticresistant infections, causing more harm and higher treatment costs. This study examined the virulence genes and antibiotic susceptibility of Vibrio cholerae and V. parahaemolyticus, two bacteria that can affect public health. A total of 32 water samples were collected from August to December 2021 from a shrimp farm in Sarawak. Vibrio cholerae (n = 10) and V. parahaemolyticus (n = 10) presumptive isolates were identified and purified using selective agar and duplex-PCR method. The results showed that 70% of V. cholerae isolates contained rtxA and 90% of V. cholerae isolates contained rtxC while tdh and trh were not found in V. parahaemolyticus isolates. Antibiotic susceptibility testing showed that all V. cholerae and V. parahaemolyticus isolates were resistant to at least one antibiotic with the mean Multiple Antibiotic Resistance (MAR) indices of 0.34 for V. cholerae and 0.24 for V. parahaemolyticus. The MAR index of 0.20 and greater indicates that antibiotics are heavily contaminating the shrimp farm water. This study highlights the need for the proper administration of antibiotics in shrimp farming environments to reduce the risk of antibiotic-resistant infections caused by V. cholerae and V. parahaemolyticus. Water treatment should also be implemented before being released back to the environment to lessen the negative impact brought by the rearing of shrimp from a highly contaminated source

The effect of mouthwash on the DNA yield and quality of oral bacteria

The application of mouthwash is one of the oral hygiene treatments that commonly use after tooth brushing to control the bacterial colonization from overgrowth. This research is focused on investigating the effect of mouthwash on oral microbiome by analyzing the quality and yield of DNA obtained before and after using mouthwash and also to compare the bacterial abundance via 16S rRNA PCR detection. Methodology and results: The DNA was extracted from the saliva samples before and after using mouthwash using Phenol-Chloroform extraction method. The DNA extract was then evaluated using Nano Drop ND-1000 UV/VIS Spectrophotometer to determine the DNA quality and DNA yield. After that, the 16S rRNA gene was amplified via PCR for bacterial detection in the saliva using 27 F and 1492 R primers set, and the PCR products were observed on 1.5% gel electrophoresis. Statistical analysis was performed by using Graphpad Prism 7.03 software. For DNA yield, there was significantly higher yield observed after mouthwash usage with 80% of the samples was found to yield more DNA. To assess DNA quality, absorbance ratio of A260/A280 and A260/A230 were used. The DNA quality was seen to be similar for both A260/A280 and A260/A230 absorbance ratio even after the usage of mouthwash. The amplification of 16S rRNA gene was successful and 1500 bp expected band size was observed. Conclusion, significance and impact of study: This study demonstrated the usage of mouthwash is useful to increase the DNA yield as compared to without using mouthwash. However in terms of quality, no difference is seen. This result can be used to provide insight on mouthwash usage for saliva sampling in a non-invasive manner

Efficiency of Detergents against Microbial Biofilm Growth in Kuching, Sarawak

Biofilms formed on these surfaces are the main cause of contamination in the final product. The attachment of bacteria to food product or the product contact surfaces leads to serious hygienic problems and economic losses due to food spoilage. Detergent is commonly used as cleaning product to mitigate the growth of microbial on the food product surface and in any food supply chain process. In this study, the efficiency of commercial detergent was analyzed against single cell of foodborne pathogens to biofilm form; Klebsiella pneumonia, Bacillus cereus and Staphylococcus aureus. The antibacterial activity of three detergent; Detergent 1, Detergent 2 and Detergent 3, were evaluated by measuring the diameter zone of inhibition using disc diffusion test. S. aureus showed the highest zone inhibition which is 27.67 ± 0.577 mm (mean ± standard deviation) whereas K. pneumonia showed the lowest zone of inhibition which is 19.97 ± 0.577 mm against Detergent 4. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined using 96-well microtiter plates. All detergents exhibited inhibitory activity against bacteria tested. D3 showed the lowest MIC and MBC of S. aureus at 0.390 mg/ml and 0.781 mg/ml respectively, whereas K. pneumonia has the highest MIC and MBC at 3.125 mg/ml and 6.25 mg/ml. The studies have been further done to test minimum bactericidal eradication concentration (MBEC) in related to biofilm eradication capacity. The MBEC result showed Detergent 3 could eradicate biofilm of S. aureus at 3.125 mg/ml. Thus, the appropriate detergent can be incorporated into food product surfaces and processing lines to mitigate the biofilm growth that potentially cause disease outbreak in future

Detection of Beneficial Lactic Acid Bacteria (LAB) and Yeast In Sarawak Fermented Food

Sarawak native’s fermented food can be a catalyst for boosting the local economy in Sarawak. The Lactic Acid Bacteria (LAB) are generally regarded as safe, have a stability of usage, and originate from natural resources. Lactic acid bacteria and yeast work in synergy to provide a natural way to enhance the nutritive value and flavour of the food. The study aims to investigate the presence of potential probiotic Lactic Acid Bacteria (LAB) and yeast isolated from Sarawak fermented food. Two hundred fifty (n=250) of samples including fifty (n=50) each sample such as fermented shrimps (cencaluk), fermented mustard vegetables (kasam ensabii), fermented fish (kasam ikan), fermented dabai (Canarium odontophyllum) and fermented fish (rusip). Molecular identification of the bacteria and yeast isolates was carried out by PCR amplification of the 16S rRNA (27F and 1492-R) and ITS (ITS5-F and ITS4-R) rRNA region. The successfully amplified PCR products were sent for Sanger sequencing As a result, a total of 45.2% (113/250) Lactic Acid Bcateria (LAB) which are 96% (48/50) of W. paramesenteroides was detected in fermented dabai, 80% (40/50) S. pasteuri in fermented fish rusip samples and 50% (25/50) in P. agglomerans in cencaluk samples. Meanwhile, yeast Candida species; 90% (45/50) of C. magnoliae and 50% (25/50) of C. parapsilosis are detected in fermented dabai and ensabi respectively. Based on the findings, both yeast and bacteriocin-producing lactic acid bacteria found in the fermented food specifically in dabai. A better understanding of microbial ecology can help the food industry to improve the foods in terms of quality and safety. The good quality of the LAB and yeast in the food such as starter culture will enhance the texture and nutritional value and Sarawak fermented food product found enriched with LAB

A preliminary study on detection of periodontal pathogens from saliva samples of selected Sarawakian

Aims: The oral cavity has the most complex microbiota after the stomach. A disturbed oral equilibrium can lead to the onset and development of periodontal disease. The known causative agents are the red complex bacteria (Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola). This study was carried out to provide insights on the prevalence of periodontal pathogens in Sarawakian oral cavity since the data at present is still lacking. Methodology and results: A total of two millilitres (2 mL) of saliva samples were collected from twenty-seven (n=27) individuals (21 gingivitis, 6 healthy) between aged 18 until 30 years old, from Sarawak General Hospital. DNA extraction for the saliva samples was done by using phenol-chloroform method. Then, 16S rRNA PCR was performed followed by species-specific PCR for red complex bacteria detection. Statistical data was analysed using GraphPad Prism 8.4.1 software. As a result, 14% of gingivitis-affected female subjects were found with all the member of red complex species. Co-occurrence of red complex species was observed but no significant difference was found. An alarming presence of red complex bacteria particularly T. forsythia was detected in 57% of gingivitis subject as compared to the other red complex species. Conclusion, significance and impact of study: The risk of acquiring periodontal disease increases by having at least one of the red complex species in the oral environment. Therefore, the rapid molecular detection of red complex bacteria in this study is useful for risk assessment of periodontal disease and proper species-targeted treatment to patients especially Sarawakian in general as the result has shed lights to the fairly poor oral status of volunteers

Onion Essential Oil-in-Water Emulsion as a Food Flavoring Agent : Effect of Environmental Stress on Physical Properties and Antibacterial Activity

Plant essential oils (EOs), which are acknowledged as generally recognized as safe (GRAS) by the Food and Drug Administration (FDA), have the potential to be used as a flavoring agent. However, there are limitations to some EOs, such as low water solubility and high volatility, which limit their application in food technology. This study was conducted to develop onion (Allium cepa) EO as a flavoring agent and determine its stability against environmental stress via an emulsification technique, with different concentrations of sodium caseinate, as a delivery system. Emulsions containing onion EO were prepared using different concentrations of sodium caseinate (3, 5, and 7% w/w) via the solvent-displacement technique. The physical properties (average droplet size, color, turbidity, and stability measurement) and antibacterial activity (agar disk diffusion method) of emulsions were then determined. Results show that emulsion with 7% (w/w) sodium caseinate was the most desirable sample in terms of physical properties and antibacterial activity. Hence, it was selected for environmental stress studies (i.e., thermal processing, freeze-thaw cycles, and ultraviolet (UV) exposure). Results revealed that all types of environmental stresses had significant (p < 0:05) effects on droplet size, color, turbidity, and stability. Generally, the environmental stresses increased the droplet size except in the freeze-thaw cycle case, while all stresses decreased the stability and lightness. All types of environmental stress treatment did not show a significant (p < 0:05) effect on antibacterial activity enhancement against Salmonella Typhimurium and Listeria monocytogenes except in the case of UV treatment against L. monocytogenes. Therefore, the present work has demonstrated the potential use of emulsion as an encapsulation and delivery system of EO flavors for food applications

Biofilm assessment of vibrio parahaemolyticus from seafood using random amplified polymorphism DNA-PCR

Pathogenic Vibrio parahaemolyticus is one of the leading causes of bacterial gastroenteritis in many countries. Among the strains examined, 36 RAPD-types were found when amplified with primers OPA8 and OPA10. The analysis shows the majority of V. parahaemolyticus isolates originated from seafood were branched into four major clusters at 18.2%, 20.7% 34% and 3.4% similarity levels. This suggests that there is potential for a single strain to be distributed widely within a population and there also potential for multiple contaminating strains of different clonal lineages to be present within the same population. Optimum temperature (37°C) was the highest and stable formation of biofilm. The total percentage of biofilm formation at 37°C was 33.33% for each of weak, moderate and strong biofilm producers. Room temperature produces 61.1% of weak biofilm producer, while 13. 89% for moderate biofilm producers and produce 25% of strong biofilm. While a total of 91.67% weak biofilm producers at 4°C and 8:33% for room temperature and no growth of strong biofilm. Upon analysis, strong biofilm was tracked from the largest group at 37°C and room temperature which produce 27.27% of strong biofilm producer respectively. Interestingly, they are derived from cockles