Stress Tolerance of Yeasts Dominating Reverse Osmosis Membranes for Whey Water Treatment

Filamentous yeast species belonging to the closely related Saprochaete clavata and Magnusiomyces spicifer were recently found to dominate biofilm communities on the retentate and permeate surface of Reverse Osmosis (RO) membranes used in a whey water treatment system after CIP (Cleaning-In-Place). Microscopy revealed that the two filamentous yeast species can cover extensive areas due to their large cell size and long hyphae formation. Representative strains from these species were here further characterized and displayed similar physiological and biochemical characteristics. Both strains tested were able to grow in twice RO-filtrated permeate water and metabolize the urea present. Little is known about the survival characteristics of these strains. Here, their tolerance toward heat (60, 70, and 80°C) and Ultraviolet light (UV-C) treatment at 255 nm using UV-LED was assessed as well as their ability to form biofilm and withstand cleaning associated stress. According to the heat tolerance experiments, the D60°C of S. clavata and M. spicifer is 16.37 min and 7.24 min, respectively, while a reduction of 3.5 to >4.5 log (CFU/mL) was ensured within 5 min at 70°C. UV-C light at a dose level 10 mJ/cm2 had little effect, while doses of 40 mJ/cm2 and upward ensured a ≥4log reduction in a static laboratory scale set-up. The biofilm forming potential of one filamentous yeast and one budding yeast, Sporopachydermia lactativora, both isolated from the same biofilm, was compared in assays employing flat-bottomed polystyrene microwells and peg lids, respectively. In these systems, employing both nutrient rich as well as nutrient poor media, only the filamentous yeast was able to create biofilm. However, on RO membrane coupons in static systems, both the budding yeast and a filamentous yeast were capable of forming single strain biofilms and when these coupons were exposed to different simulations of CIP treatments both the filamentous and budding yeast survived these. The dominance of these yeasts in some filter systems tested, their capacity to adhere and their tolerance toward relevant stresses as demonstrated here, suggest that these slow growing yeasts are well suited to initiate microbial biofouling on surfaces in low nutrient environments

Effect of Serving Time on Microbiological Quality of Food Served (Chicken Dish and Rice) During Wedding Banquet

Ayam masak merah (chicken in tomato sauce) and nasi minyak (flavoured ghee rice) are among the common dish served in Malay wedding banquet. The microbiological quality of these dishes becomes a concern when there was a food poisoning that caused four deaths after attending the wedding banquet. Therefore, the aim of this work is to investigate the microbiological quality of ayam masak merah and nasi minyak during the serving time (0, 1, 2, 3 and 4 hours) at the wedding banquet. The microbiological analysis were; total plate count (TPC), total coliform, Escherichia coli , Staphylococcus aureus, Bacillus cereus, Salmonella spp., and Listeria spp. The results showed that ayam masak merah has the highest count for TPC, total coliform, Escherichia coli, Staphylococcus aureus, but low count in Listeria spp. and Salmonella spp. was not detected. Highest TPC was observed at the first hour of serving time, 7.33 log CFU/g, while for total coliforms and Staphylococcus aureus was at the 4 hours of serving time, 7.44 log CFU/g and 7.27 log CFU/g respectively

Effect of fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) on microbial quality and sensory acceptability of frozen paratha

Fennel (Foeniculum vulgare Mill.) and coriander (Coriandrum sativum L.) are known to possess good antimicrobial properties. In the present work, spice-infused frozen parathas were formulated to investigate the effect of fennel and coriander on microbial (aerobic mesophilic bacteria, yeast and mould, and Bacillus cereus) reduction and sensory acceptability of frozen paratha throughout the storage at -18°C. The present work was also aimed at determining the relationship between spice concentrations and storage durations on microbiological quality of the samples. Fennel and coriander seed powder were used at concentrations of 2, 4 and 6% of wheat flour (w/w). The microbiological analysis was performed by total plate count, yeast and mould count, and Bacillus cereus count after 9, 12 and 15 weeks of storage. Sensory evaluation was conducted using hedonic scales at the end of storage durations. Results showed that spice infusion in frozen paratha significantly delayed the growth of aerobic mesophilic bacteria, yeasts and moulds, and Bacillus cereus during storage. The lowest log count was demonstrated by coriander at 6% in total plate count (3.85, 3.90 and 3.91 log10 CFU/g), and yeast and mould count (2.54, 2.59 and 2.60 log10 CFU/g) after 9, 12 and 15 weeks, respectively. Bacillus cereus was not detected throughout the storage durations. Fennel exhibited minimum activity against Bacillus cereus with no significant difference on log count reduction when compared with control. Coriander showed the highest decrease in both total plate count and Bacillus cereus count during the storage duration. Sensory evaluation result indicated that control sample exhibited the highest preference over all attributes when compared with fennel and coriander. Coriander-infused paratha was slightly darker in colour due to high concentration of 6%. Fennel yielded the lowest score in terms of taste among all samples. Fennel and coriander showed no significant difference for sensory acceptability. Overall, all frozen parathas were in good quality after 15 weeks of frozen storage. It can thus be concluded that fennel and coriander can be used as potential natural preservatives to inhibit the growth of microorganisms in paratha during frozen storage. Nevertheless, the optimum spice concentration should be determined to minimise the effects on the sensory attributes

Isolation of Bacteria from Psophocarpus Tetragonolobus and Biofilm Formation

Vegetables are easily spoiled by different microorganisms with bacterial and fungal species during processing. Usually, vegetables are serving as carrier for pathogenic bacteria, parasites and viruses and lead to food borne illness outbreaks. The winged bean (Psophocarpus tetragonolobus) species is goes to the genus Psophocarpus, a tropical legume plant commonly known as the Goa bean, Manila bean, four-angled bean or four-cornered bean and Mauritius bean. The ability of bacteria to attached on surfaces and form a distinct biofilm can lead to food spoilage. Biofilm formation relies on three main parameters including the bacterial cells, the surface attached, and the surrounded medium but the attachment of bacteria to the surface is the initial process of biofilm. This research conducted to isolate bacteria from the winged bean and to determine biofilm formation. Throughout the study, four different types of bacteria were isolated from winged bean such E. coli, Listeria, Salmonella, and Shigella. Then, all the isolated bacteria were further analyzed for biofilm formation. As the results, only E. coli bacteria show the ability to form a biofilm on winged bean at room temperature. The other bacteria such as Listeria, Salmonella, and Shigella have not shown the biofilm formation. This could be due to the environment, temperature or the sample size which not being favourable factors for the formation. However, there is an urgent need to ensure the microbiological safety in food industries, especially in processed foods, like fresh-cut vegetables, in such a way that the lack of heat treatment does not promote the growth of potentially pathogenic microorganisms

Toxic Elements in Food: Occurrence, Binding, and Reduction Approaches

Toxic elements such as mercury, arsenic, cadmium, and lead, sometimes called heavy metals, can diminish mental and central nervous system function; elicit damage to blood composition as well as the kidneys, lungs, and liver; and reduce energy levels. Food is considered one of the main routes of their entry into the human body. Numerous studies have been performed to examine the effects of common food processing procedures on the levels of toxic elements in food. While some studies have reported negative effects of processing, several have shown that processing practices may have a positive effect on the reduction of toxic elements in foodstuffs. A number of studies have also introduced protocols and suggested chemical agents that reduce the amount of toxic elements in the final food products. In this review, the reported methods employed for the reduction of toxic elements are discussed with particular emphasis on the chemical binding of both the organic and inorganic forms of each element in various foods. The molecular groups and the ligands by which the food products bind with the metals and the types of these reactions are also presented

Microbiological quality of municipal tap water and filtered drinking water in Serdang, Selangor

Microbiological quality is one of the primary indicators of the safety of drinking water supply. Contaminated municipal and drinking water may result in waterborne diseases like gastrointestinal illness or diarrhea. The microbiological quality of tap water from municipal water supplies and drinking water from water cooler were comparatively studied. Heterotrophic plate count (HPC) and total coliform (TC) were enumerated from both samples that collected from Serdang area. The method used in this study for water analysis was membrane filtration (MF) method with using acetate cellulose membrane filter (0.45 mm). The heterotrophic plate count was found not significantly different (p > 0.05) in municipal tap water (MTW) and filtered drinking water (FDW), which was 1.60 log10 cfu ml-1 and 1.45 log10 cfu ml-1, respectively. For total coliform, MTW (1.44 log10 cfu ml-1) were found significantly (P ≤ 0.05) higher compared to FDW (1.00 log10 cfu ml-1). Heterotrophic plate count in MTW and FDW among the samples were not significantly different (p > 0.05) with the range value is 1.51 to 1.71 log10 cfu ml-1 and 1.01 to 1.65 log10 cfu ml-1 respectively. In conclusion, FDW possesses lower heterotrophic plate count and total coliform count than MTW, and microbiological quality of the drinking water system depends on regular cleaning of filters in the water cooler to ensure the safety of the water cooler users

Proper hand washing practices in school canteen: a qualitative study on food handlers' belief

Improving hand washing practice among food handlers is one of the ways to reduce food borne illness. This study aimed to assess behavioural belief, normative and control beliefs underpinning food handlers’ decision to perform hand washing practices in school canteen in Malaysia. A qualitative study comprising eight focus group discussions with 71 food handlers were conducted to elicit the underlying belief specific to hand washing practices. Respondents from school canteen within Klang Valley were recruited using purposive sampling strategy. All focus group audio recordings were transcribed verbatim. A thematic content analysis was conducted using Atlas.ti software to code, manage and analyze data. Results obtained from the focus group discussions were coded according to key concepts in the Theory of Planned Behaviour (TPB) framework which explain behavioural belief (i.e. advantages and disadvantages of hand washing), normative belief (i.e. an individual’s perception of social normative pressure) and control belief (i.e. barriers and facilitators) to perform hand washing. Themes emerge for the advantages of proper hand washing are cleanliness, prevent bacteria/virus infection, reduce food poisoning risk, while the disadvantages are time pressure, hassle, and work load pressure. The barriers for proper hand washing identified were time pressure, work load pressure, the frequency of hand washing required, steps in proper hand washing, and availability of hand washing soap. The facilitators for hand washing practices include poster reminder, reminder from manager/owner and rewards/punishment from manager/owner. Themes found under normative belief are the influence from school administration, manager, co-worker and health inspector. In summary, all the beliefs elicited may provide valuable information for the development and evaluation of intervention strategies to improve food handlers’ proper hand washing practices

Arabic as Foreign Language Learning in Pandemic COVID-19 as Perceived by Students and Teachers

Teaching and learning process using mobile application becomes one of alternative tools to substitute face-to-face learning during Pandemic Covid-19. The lecture process during the period has been experienced since March 2020 until the end of the even semester of the academic year 2019/2020. There were various obstacles felt by lecturers and students in the courses. Under normal conditions, learning Arabic as a foreign language is still faced with various problems. Since, there are no specific studies in this issues that have been conducted by experts for Indonesian context, we are interested to identify the perception of students and lecturers on the quality of Arabic teaching and learning process. This research uses qualitative method where the sources of data are students and lecturers of Arabic language education study program Faculty of Islamic Studies, Muhammadiyah University of West Sumatra. The data collection taken from interview by phone. The finding showed that the students and lecturers' perceptions of the quality of the online learning process are negative. Then, students' and lecturers' perceptions of the quality of online Arabic learning outcomes are negative