The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future.
1 February 2019 in Saudi Journal of Biological Sciences
Aflatoxins (AFS) are toxic and carcinogenic fungal metabolites. Aflatoxin B1 is the most toxic and has been classified as a Group I carcinogen by the International Agency for Research on Cancer (IARC). Samples of imported rice were analyzed for their AFS content. Finley ground rice subsamples were extracted with water/methanol (100:150 v/v) followed by purification with Immunoaffinity columns (IAC). AFS purified from extracts were determined with RP-HPLC-FLD using post column electrochemical derivatization with a Kobra Cell. Concentrations of aflatoxin B1 and total AFS in test rice samples were ≤0.123 and ≤2.58 µg/kg, respectively. Tween 80 improved recoveries (86 and 106%) of aflatoxin B1 and aflatoxin G1 from brown rice. Recoveries of Aflatoxin B2 and aflatoxin G2 were substantially reduced (non-detected to 27%) by Tween 80 used in IAC cleanup of brown rice extracts. Visible dense growth of Aspergillus parasiticus (food isolate) occurred at 25 °C but higher aflatoxin B1amounts (23.9-39.3 µg/kg) accumulated when the mold grew at 37 °C in rice seeds stored for three weeks. It could be concluded that levels of aflatoxin B1 and total AFS in rice samples were within the permissible amounts of the EU and other international legislations.
The microbial contamination of 60 samples from six date cultivars in therutabstage purchased from different retail outlets in AL-Hofuf City, Saudi Arabia was studied. All samples were found contaminated with aerobic mesophilic bacteria at loads in the order 102to 105 cfu/cm2with some significant differences among varieties that can be attributed to differences in the weather conditions duringrutabseason. Also all samples, except only one, were contaminated with molds and yeasts at loads in the order 102to 103 cfu/cm2. Potentially pathogenicStaphylococcus aureuswas detected in 57 samples andA. flavus/parasiticusin 13 samples, while coliforms were detected in 39 samples.
1 January 2024 in Journal of Food Processing and Preservation
Red beetroot is a unique vegetable crop with high nutritional value and various health benefits, but due to the short shelf life, it requires a suitable preservation method. The purpose of the current investigation is to study the impacts of pretreatment coating with gum Arabic and drying method (oven, microwave, and freeze‐drying) on the quality parameters and storage stability of beetroot slices. Freeze‐dried beetroot samples showed the lowest moisture content (MC) (7.59%) and the highest rehydration ratio (RR) (5.47), betalain content (48.57 mg/100 g), antioxidant activity (70.92%), and overall acceptability scores (4.48). Generally, the pretreatment coating with gum Arabic reduced the degradation of betalain and antioxidants and maintained higher sensory scores of dried beetroot samples compared to uncoated ones. The beetroot extract prepared from freeze‐dried and coated with gum Arabic samples decreased the oxidation of low‐density lipoprotein (LDL) compared to control. Freeze‐dried samples coated with gum Arabic revealed higher storage stability (after 4 weeks of storage at room temperature) in terms of betalain content and antioxidant activity with values of 43.84 mg/100 g and 67.02%, respectively, compared to uncoated ones which recorded 35.15 mg/100 g and 64.22% for betalain content and antioxidant activity, respectively. Generally, freeze‐drying and coating with gum Arabic is considered a promising treatment to maintain the quality and storage stability of dried beetroot slices. Further investigations including nutritional, technological, and economic aspects are required for the optimum application in the future.
Introduction: Ensuring hospital food safety is essential for patient health, infection control, and public trust. This study evaluates food exposure risks in two hospitals in Al-Ahsa Governorate, Saudi Arabia, focusing on critical control points during food processing and delivery.Methods: Microbial analysis was conducted on food samples from various stages of food preparation, including raw meat, chicken, fish, and prepared meals. Temperature monitoring and chemical hazard assessments were also carried out, including pesticide residue and heavy metal analysis.Results: The microbial analysis detected specific pathogens, including Salmonella, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus, along with yeasts and molds. Total bacterial counts (TBC) in raw meat, chicken, and fish ranged from 2.5 to 5.0 log cfu/g, while prepared meals had TBCs between 1.0 and 3.0 log cfu/g. No Salmonella or Listeria monocytogenes were detected. Chemical hazards, including mycotoxins in white flour and heavy metals, were within permissible limits. However, 12 pesticides were detected, with six exceeding European Food Safety Organization limits.Discussion: Temperature monitoring revealed that hot foods cooled to unsafe levels during transport, and cold samples were not consistently maintained at SFDA-recommended temperatures. Hospitals generally comply with health regulations but improvements are necessary in temperature control and preventing chemical contamination of raw materials.
17 October 2023 in Arab Gulf Journal of Scientific Research
Purpose: Fresh vegetables contain advantageous phytochemical components, making them one of the most significant sources of nutrition. The threat of harmful bacteria still exists because these vegetables are not heated in restaurants before being consumed. Therefore, this study aimed to evaluate the microbial quality of fresh vegetables in restaurants of different levels.Design/methodology/approach: A total of 499 fresh vegetable samples (from sandwiches and fresh-cut vegetable salads) were collected from 3 different types of food service establishment: 201 from international restaurants (IRs), 210 from national restaurants (NRs), and 88 from cafeterias (CAs). The samples were prepared and inoculated on specific growth media. The aerobic mesophilic bacteria (AMB) Campylobacter spp., Staphylococcus aureus(S. aureus), Enterobacteriaceae, Escherichia coli(E. coli) and yeast and molds were counted, and Listeria monocytogenes, Salmonella spp. and Escherichia coli O157 were detected using specialized medium.Findings: High counts of S. aureus, above 3 log cfu/g, suggested that 71.5% of samples collected from NRs and 77.3% from CA were not accepted, whereas 81.6% of samples collected from IRs were accepted. The low population of E. coli, less than 2 log cfu/g, suggested that 99.0, 97 and 92.0 % of samples collected from IRs, NRs and CA, respectively, were accepted. Listeria monocytogenes and Escherichia coli O157 were absent from every sample. One sample was positive for Salmonella spp. in each of the NR and CA sample groups.Originality/value: RIs adhere to health and hygiene standards better than NRs and CAs, according to the findings of vegetable contamination tests.