Intraoperative liver deformation and organ motion caused by ventilation, laparotomy, and pneumoperitoneum in a porcine model for image-guided liver surgery.

BACKGROUND: Image-guidance promises to make complex situations in liver interventions safer. Clinical success is limited by intraoperative organ motion due to ventilation and surgical manipulation. The aim was to assess influence of different ventilatory and operative states on liver motion in an experimental model. METHODS: Liver motion due to ventilation (expiration, middle, and full inspiration) and operative state (native, laparotomy, and pneumoperitoneum) was assessed in a live porcine model (n = 10). Computed tomography (CT)-scans were taken for each pig for each possible combination of factors. Liver motion was measured by the vectors between predefined landmarks along the hepatic vein tree between CT scans after image segmentation. RESULTS: Liver position changed significantly with ventilation. Peripheral regions of the liver showed significantly higher motion (maximal Euclidean motion 17.9 ± 2.7 mm) than central regions (maximal Euclidean motion 12.6 ± 2.1 mm, p < 0.001) across all operative states. The total average motion measured 11.6 ± 0.7 mm (p < 0.001). Between the operative states, the position of the liver changed the most from native state to pneumoperitoneum (14.6 ± 0.9 mm, p < 0.001). From native state to laparotomy comparatively, the displacement averaged 9.8 ± 1.2 mm (p < 0.001). With pneumoperitoneum, the breath-dependent liver motion was significantly reduced when compared to other modalities. Liver motion due to ventilation was 7.7 ± 0.6 mm during pneumoperitoneum, 13.9 ± 1.1 mm with laparotomy, and 13.5 ± 1.4 mm in the native state (p < 0.001 in all cases). CONCLUSIONS: Ventilation and application of pneumoperitoneum caused significant changes in liver position. Liver motion was reduced but clearly measurable during pneumoperitoneum. Intraoperative guidance/navigation systems should therefore account for ventilation and intraoperative changes of liver position and peripheral deformation.

Assessment of the quality of root canal fillings performed on extracted teeth by undergraduate dental students in a sample from Saudi Arabia.

BACKGROUND: The educational process in the field of endodontics commences with preclinical exercises to enhance students' proficiency in cleaning, shaping, and performing root canal fillings. Therefore, this study aimed to radiographically evaluate the technical quality of root canal fillings performed by preclinical students on extracted teeth at the College of Dentistry, University of Ha'il, Saudi Arabia. METHODS: A total of 788 extracted human teeth received root canal treatment by undergraduate students. The samples were then gathered and radiographically assessed using the three quality criteria of length, density, and taper. The category of root canal fillings was classified as either acceptable or unacceptable. The criteria for evaluating the acceptability of filling quality were defined based on the presence of adequate length, density, and taper. The effectiveness of root canal fillings was also evaluated in relation to the tooth type, sex, and treatment year. The agreement between the examiners was evaluated using Cohen's kappa test, and the relationship between the research variables was determined using the chi-squared test. The significance threshold was set at 0. 05. RESULTS: The overall quality of root filling was determined to be satisfactory in 532 (67.5%) of 788 endodontically treated extracted teeth. The majority of the research sample (88.1%) had enough length, 89.6% had adequate density, and 86.4% had acceptable taper. The quality of anterior teeth was substantially better than that of posterior teeth (p < 0.001). Our findings showed that the quality of root canals was better in 2022 than it had been in earlier years (p = 0.001). The three RCT quality criteria differed significantly when compared between sexes (p = 0.002). CONCLUSIONS: The quality of the root canal fillings completed by undergraduate students was rated as acceptable. The findings of the research suggest that the implementation of routine assessments to evaluate the technical competence of undergraduate dental students performing root canal treatments could provide significant insights into the efficacy of the curriculum requirements.

A worldwide review of illness outbreaks involving mixed salads/dressings and factors influencing product safety and shelf life.

The trends toward healthy living, vegetarianism, and busy schedules have increased salad popularity. Salads are usually consumed raw without any thermal treatment, and therefore, without proper care they can become major vehicles for foodborne illness outbreaks. This review examines the microbial quality of 'dressed' salads which contain two or more vegetables/fruits and salad dressings. The possible sources of ingredient contamination, recorded illnesses/outbreaks, and overall microbial quality observed worldwide, besides the antimicrobial treatments available are discussed in detail. Noroviruses were most frequently implicated in outbreaks. Salad dressings usually play a positive role in influencing microbial quality. However, this depends on several factors like the type of contaminating microorganism, storage temperature, dressing pH and ingredients, plus the type of salad vegetable. Very limited literature exists on antimicrobial treatments that can be used successfully with salad dressings and 'dressed' salads. The challenge with antimicrobial treatments is to find ones sufficiently broad in spectrum, compatible with produce flavour which can be applied at competitive cost. It is evident that renewed emphasis on prevention of produce contamination at the producer, processor, wholesale and retail levels plus enhanced hygiene vigilance at foodservice will have a major impact on reducing the risk of foodborne illnesses from salads.

Detection of Salmonella Enteritidis in Milk Using Conductometric Immunosensor Coated on Polyaniline/Zinc Oxide Nanocomposite.

The demand for rapid and accurate detection methods for Salmonella Enteritidis necessitates the development of highly sensitive and specific biosensors to ensure proper monitoring of food safety and quality requirements in the food sector and to secure human health. This study focused on development of a polyaniline/zinc oxide (PANI/ZnO) nanocomposite film on a gold electrode conductometric immunosensor for detection of Salmonella Enteritidis. The sensor was modified with monoclonal anti-Salmonella Enteritidis antibodies as biorecognition elements. The fabricated sensor was able to detect and quantify the target pathogen within 30 min and showed a good detection range from 101 to 105 colony-forming units (CFU)/mL for Salmonella Enteritidis and a minimum detection limit of 6.44 CFU/mL in 0.1% peptone water. Additionally, the fabricated sensor showed good selectivity and detection limit toward the target bacterium and successfully determined Salmonella Enteritidis content in ultrahigh heat-treated skim milk samples without pretreatment of the food sample.

Virulence, antimicrobial susceptibility and phylogenetic analysis of Cronobacter sakazakii isolates of food origins from Jordan.

AIMS: The aim was to characterize a collection of Cronobacter sakazakii isolates collected from various origins in Jordan. METHODS AND RESULTS: The isolates were characterized using 16S rRNA sequencing, DNA microarray, multi-locus sequence typing (MLST), O-serotyping, virulence gene identification and antibiotic susceptibility testing. The identities and phylogenetic relatedness revealed that C. sakazakii sequence type 4 (ST4) and Csak O:1 serotype were the most prevalent STs and serovars amongst these C. sakazakii strains. PCR screening of putative virulence genes showed that the siderophore-interacting protein gene (sip) and iron acquisition gene clusters (eitCBAD and iucABCD/iutA) were the most detected genes with noticeable variability in the type 6 secretion system (T6SS) and filamentous hemagglutinin/adhesion (FHA) gene loci. The antibiotic resistance profiles revealed that the majority of the isolates were susceptible to all antibiotics used despite harbouring a class C ß-lactamase resistance gene. CONCLUSIONS: The results described in this report provide additional insights about the considerable genotypic and phenotypic heterogeneity within C. sakazakii. SIGNIFICANCE AND IMPACT OF THE STUDY: The information reported in this study might be of great value in understanding the origins of C. sakazakii isolates, in addition to their diversity and variability, which might be helpful in preventing future outbreaks of this pathogen.

How has public perception of food safety and health risks changed a year after the pandemic and vaccines roll out?

The recent coronavirus pandemic (COVID-19) has caused unprecedented turmoil and spurred fears that have profoundly changed the public's social and health behaviours, including the perception of food safety risks. One year after the pandemic and the global vaccination campaign, the public perception of food safety and the changes in their hygiene behaviour, health risks concerns, and trust were studied in Jordan, Lebanon, and Tunisia using a cross-sectional online survey. The results of 538 subjects showed a rise in the frequency of hygiene practices, notably in handwashing. Sixty-four percent of the participants were vaccinated, a proportion made up mainly of the Jordanians and Lebanese. For 66% and 64% of the two population groups, respectively, there were no longer trust concerns about COVID-19 health risks following vaccination, whereas the worries about getting COVID-19 persisted for others. Only 47% of participants trusted eating food prepared by vaccinated food handlers. A great majority of the Tunisians (81%) showed varying degrees of concern about COVID-19 transmission from food and the lowest vaccination rate (33%). The current study demonstrated that the impact of vaccination policy positively affects public perception of food-related risks during the pandemic. On the other hand, 33% of the surveyed Jordanians and Tunisians lost trust in the health authorities' management of the pandemic, and 45% of the Lebanese still don't trust them. Communication strategies on health and food safety with the public still represent a challenge for these and probably other countries in the Middle East and North Africa (MENA). Strategies for building and maintaining public trust are crucial to curb persistent fear of food, hence, avoiding potential stigmatization affecting the food economy by promoting health awareness and positive changes in food safety perceptions for safer practices.

Workplace violence toward emergency medicine physicians in the hospitals of Taif city, Saudi Arabia: a cross-sectional survey.

BACKGROUND: Workplace violence against health care workers is an emerging concern in various global health settings and the documentation of physical and verbal attacks against physicians in tertiary hospitals in Saudi Arabia is uncommon. This study aimed to determine the incidence of workplace violence against physicians in the emergency department of selected tertiary hospitals in Taif City, Saudi Arabia from June to July 2021. Associations between the incidence of violence and interventions and type of physicians and years of experience were also investigated. METHODOLOGY: Using a cross-sectional design, a total of 96 physicians were recruited to answer the World Health Organization Questionnaire on Violence against Health Care Workers last June to July 2021. RESULTS: It was found out that 75 physicians (78.1%) experienced verbal violence while 14 physicians (14.6%) experienced physical violence. Most of the workplace violence happened within hospital premises (84.4%). Despite having an experience of verbal and physical violence, only 44.8% of the respondents reported the incidents. The most common instigators were patients (55.21%), their relatives (78.00%), external colleagues (9.37%) and staff members (6.25%). Most respondents took no action, or reported the incidence to the police or senior staff member. The incidence of workplace violence and type of physician showed significant association. The number of years of practice in emergency medicine also exhibited statistically significant association with the incidence of verbal attack, frequency of violence, and location of incident. CONCLUSION: There is high incidence of workplace violence among physicians in tertiary hospitals, and younger physicians with less experience in emergency medicine were the most susceptible to both verbal and physical violence. There is a need to strengthen policies to protect physicians against workplace violence.

Duty to Work During the COVID-19 Pandemic: A Cross-Sectional Study of Perceptions of Health Care Providers in Jordan.

INTRODUCTION: This study aimed to assess perceptions of duty to work among health care providers during the coronavirus disease 2019 response and to identify factors that may influence their perceptions. METHODS: This was a cross-sectional study conducted from April 1, 2020, to April 20, 2020, using an online survey distributed to health care providers in Jordan. Descriptive statistics were used, as well as chi-square test for independence to assess relationships between variables. RESULTS: A total of 302 questionnaires were included. Commitment to serve the community was the primary reason for coming to work (36%), followed by commitment to faith (29.6%). The major perceived barriers for coming to work were lack of appropriate personal protective equipment and appropriate training (62.6% and 53.5%, respectively). Males perceived higher work obligations than females in all potential barriers (P < .05), except for the lack of appropriate training. Nurses perceived higher work obligations than other health care providers despite the lack of appropriate training (χ2 = 11.83, P = .005), lack of effective vaccine or treatment (χ2 = 21.76, P < .001), or reported infection among coworkers (χ2 = 10.18, P = .03). DISCUSSION: While the majority of health care providers perceive an obligation to work during the coronavirus disease 2019 pandemic, specific conditions, mainly lack of protective gear and training, may significantly alter their perception of work obligation. Providing training and proper personal protective equipment are among the vital measures that could improve the work environment and work obligation during pandemic conditions.

Back pain as an initial feature of advanced gastric cancer mimicking multiple myeloma: A case report and literature review.

BACKGROUND: Back pain is a rare initial presentation of gastric cancer. Isolated back pain with red flags in middle-aged patients might indicate multiple myeloma. However, it is rarely present in advanced gastric adenocarcinoma; hence, data are limited to case reports only. For a timely diagnosis of the underlying malignancy, endoscopy should be considered if the initial workup for this backache is unrevealing. CASE PRESENTATION: We present a 34-year-old previously healthy gentleman with severe unremitting backache. He was ultimately diagnosed with gastric adenocarcinoma stage IV and received palliative treatment. The manuscript also reviewed relevant literature. CONCLUSION: In rare cases, gastric malignancy can initially present as back pain with lytic bone lesions, mimicking multiple myeloma. Endoscopy early in the course of investigations may help reduce associated morbidities. Further, more extensive studies are required to understand better the clinical characteristics, demographics, and management of such patients.

Effects of laparoscopy, laparotomy, and respiratory phase on liver volume in a live porcine model for liver resection.

BACKGROUND: Hepatectomy, living donor liver transplantations and other major hepatic interventions rely on precise calculation of the total, remnant and graft liver volume. However, liver volume might differ between the pre- and intraoperative situation. To model liver volume changes and develop and validate such pre- and intraoperative assistance systems, exact information about the influence of lung ventilation and intraoperative surgical state on liver volume is essential. METHODS: This study assessed the effects of respiratory phase, pneumoperitoneum for laparoscopy, and laparotomy on liver volume in a live porcine model. Nine CT scans were conducted per pig (N = 10), each for all possible combinations of the three operative (native, pneumoperitoneum and laparotomy) and respiratory states (expiration, middle inspiration and deep inspiration). Manual segmentations of the liver were generated and converted to a mesh model, and the corresponding liver volumes were calculated. RESULTS: With pneumoperitoneum the liver volume decreased on average by 13.2% (112.7 ml ± 63.8 ml, p < 0.0001) and after laparotomy by 7.3% (62.0 ml ± 65.7 ml, p = 0.0001) compared to native state. From expiration to middle inspiration the liver volume increased on average by 4.1% (31.1 ml ± 55.8 ml, p = 0.166) and from expiration to deep inspiration by 7.2% (54.7 ml ± 51.8 ml, p = 0.007). CONCLUSIONS: Considerable changes in liver volume change were caused by pneumoperitoneum, laparotomy and respiration. These findings provide knowledge for the refinement of available preoperative simulation and operation planning and help to adjust preoperative imaging parameters to best suit the intraoperative situation.

Antagonistic effects of Lactobacillus reuteri against Escherichia coli O157:H7 in white-brined cheese under different storage conditions.

This study aimed to investigate the survival of the foodborne pathogen Escherichia coli O157:H7 in white-brined cheeses as influenced by the presence of Lactobacillus reuteri. The white cheeses were made from pasteurized bovine milk inoculated with E. coli O157:H7 (cocktail of 3 strains) to achieve ∼5 log10 cfu/g with absence or presence of Lb. reuteri (∼6 log10 cfu/g). Cheese samples were brined in 10% or 15% NaCl solution and stored at 10°C and 25°C for 28 d. The white-brined cheeses were assessed for salt content, pH, water activity (Aw), and numbers of E. coli O157:H7, Lb. reuteri, nonstarter lactic acid bacteria (NSLAB), yeasts, and molds. Results showed that E. coli O157:H7 survived in cheese stored in both brine solutions at 10°C and 25°C regardless of the presence of Lb. reuteri. A substantial reduction was observed in cheese stored in 10% NaCl brine at 25°C, followed by cheese stored in 15% NaCl brine at 10°C by 2.64 and 2.16 log10 cfu/g, respectively, in the presence of Lb. reuteri and by 1.02 and 1.87 log10 cfu/g, respectively, in the absence of Lb. reuteri under the same conditions. The pathogen in brine solutions survived but at a lower rate. Furthermore, the growth of Lb. reuteri and NSLAB were enhanced or slightly decreased in cheese and brine by 28 d, respectively. The salt concentrations of cheese ranged from 4 to 6% and 5 to 7% (wt/wt), during 28-d ripening in 10 and 15% brine, respectively. Values of pH and Aw slightly increased at d 1 after exposure to brine and reached 4.69 to 6.08 and 0.91 to 0.95, respectively, in all treatments. Therefore, the addition of Lb. reuteri can be used as a biopreservation method to inhibit the survival of E. coli O157:H7 in white-brined cheese when combined with the appropriate temperature, NaCl level, and storage time.

Aurintricarboxylic acid and its metal ion complexes in comparative virtual screening versus Lopinavir and Hydroxychloroquine in fighting COVID-19 pandemic: Synthesis and characterization.

The salt of Aurintricarboxylic acid (ATA) was utilized in this study to synthesize new alkaline earth metal ion complexes. The analytical results proposed the isolation of mononuclear (Sr+2&Ba+2) and binuclear complexes (Mg+2&Ca+2). These complexes were analyzed by available analytical and spectral techniques. The tetrahedral geometry was suggested for all complexes (SP3) through bidentate binding mode of ligand with each central atom. UV-Vis spectra reveal the influence of L â†’ M charge transfer and the estimated optical band gap mostly appeared close to that for known semiconductors. XRD, SEM and TEM studies were executed for new complexes and reflects the nano-crystallinity and homogeneous morphology. The structural forms of ATA and its complexes were optimized by DFT/B3LYP under 6-31G and LANL2DZ basis sets. The output files (log, chk &fchk) were visualized on program screen and according to numbering scheme, many physical features were obtained. It is worthy to note that, a virtual simulation for the inhibition affinity towards COVID-19 proteins as proactive study before the actual application, was done for ATA and its complexes. This was done in addition to drugs currently applied in curing (Hydroxychloroquine & Lopinavir), for comparison and recommendation. Drug-likeness parameters were obtained to evaluate the optimal pharmacokinetics to ensure efficacy. Furthermore, simulated inhibition for COVID-19 cell-growth, was conducted by MOE-docking module. The negative allosteric binding mode represents good inhibitory behavior of ATA, Ba(II)-ATA complex and Lopinavir only. All interaction outcomes of Hydroxychloroquine drug reflect unsuitability of this drug in treating COVID-19. On the other hand, there is optimism for ATA and Lopinvir behaviors in controlling COVID-19 proliferation.

The public perception of food and non-food related risks of infection and trust in the risk communication during COVID-19 crisis: A study on selected countries from the Arab region.

The coronavirus pandemic caused a state of panic worldwide. Mixed messages were given about its risk and how to contain it, when trust in authorities and reliable scientific information are essential to reduce unnecessary scares and inappropriate risk perceptions. We know little about public concerns and opinions in health authorities in the Arab world. Thus, an attempt was made to generate such information through a web-based survey. A total of 1074 subjects from Lebanon, Jordan, and Tunisia were recruited to explore their perception of food and non-food risks of infection and the influence of the source of information, trust, and attitudes towards the local authorities' communication of risk. Seventy percent of the respondents were concerned that COVID-19 may be transmitted through food. The perception of risk from touching contaminated surfaces and food packaging and being exposed to infected people during food shopping was even higher. For only less than half of the respondents, the information from local authorities was considered trustworthy and the associated risk communication and response to false rumors were timely, effective, and clear. But the satisfaction level among the Jordanians was remarkably stronger than for the Lebanese and Tunisian respondents. The demographic factors, trust in information, and attitudes towards authorities' performance in risk communication did not influence risk perceptions. Respondents' knowledge was limited based on their chief sources of information, such as social media, local news media broadcasts, and announcements by the World Health Organization. Our conclusion is that unnecessary fear increases among the public when risks that impact heath are unknown. More research in the Arab region is needed to understand the determinants of risk perceptions considering psychological factors on the risk to health. Unfortunately, it is difficult to restrict or contain misleading information from various forms of social media. We recommend that for reducing fear and building confidence with the public for appropriate action during the pandemic, local authorities should enhance the quality and level of details of the information that they share during such crises.

An on-line survey of the behavioral changes in Lebanon, Jordan and Tunisia during the COVID-19 pandemic related to food shopping, food handling, and hygienic practices.

The impact of the novel coronavirus pandemic (COVID-19) has spanned across the various aspects of life globally. Understanding public reactions is vital for effective risk communication and outbreak control and prevention. The Arab world has diverse cultural, economic, and social structures, so public choices and decisions also vary. To investigate the changes in behavior related to food shopping and handling, precautions measures, and hygiene practices of the public during the pandemic, a web-based survey tool was developed and conducted on 1074 subjects in three Arab countries, Lebanon, Jordan, and Tunisia, using a snowball sampling technique. The results showed a significant reduction in RTE consumption during the pandemic, as shown in the 19.2% and 12.2% rise in the proportion of respondents not ordering hot and cold RTE food delivery, respectively. Compared to pre-COVID-19 times, a substantial increase in behaviors related to hygiene and disinfection practices (22.0%-32.2%) was observed with a lesser increase (11.2%) in handwashing practices before food preparation. Moreover, public concerns about contracting COVID-19 from food led to almost doubling the number of Tunisians using cleaning agents for washing fresh fruits and vegetables (e.g., soaps, non-food grade chlorine bleach) besides a 16% and 26.1% increase in use among the Jordanian and Lebanese, respectively. However, a third of the respondents did not follow instructions on labels for the use of chemical products. In conclusion, this study identified culture-specific shortfalls in handwashing and unsafe food handling practices during COVID-19 in the Arab countries and sheds light on the paramount role of coordinated efforts between the local health authorities and the food safety and public health stakeholders in risk communication. To reduce health risks, there need to be rigorous educational campaigns and targeted messages that reach out to the general audience on hand hygiene, the health effects of haphazard use of unsafe chemical compounds on food, and recommendations on following label instructions.

Knowledge and Practice of Burn First Aid Among Saudi Arabian Medical and Non-Medical University Students.

Burns are serious injuries, resulting in high morbidity and healthcare costs. Effective first aid improves outcomes. The aim of this study was to assess the knowledge and practice of first aid for burn injuries among medical and non-medical students in Saudi Arabia. A cross-sectional study (N = 408) was conducted, in which a questionnaire was administered assessing students' experience with burns, as well as their hypothetical responses to vignettes involving patients with burn injuries. Although most students reported having personal experience with burns, and had received some information regarding burn first aid, only about half were able to provide correct responses regarding first aid techniques, and medical students were no more accurate than non-medical students in their responses. Results suggest that members of the Saudi Arabian population may lack appropriate knowledge about burn first aid, and education and public information resources may help to remedy this problem.

Microbiological quality of kitchens sponges used in university student dormitories.

BACKGROUND: Kitchen sponges are a major source of cross-contamination as they can transfer foodborne pathogens, infectious agents and spoilage causing microorganisms to food contact surfaces. Several studies have revealed that university students adopt poor practices regarding food safety, hygiene, and the handling of kitchen cleaning equipment. METHODS: A total of fifty kitchen sponges were collected along with a questionnaire addressing social demographics and kitchen sponge usage by students living at the University of Sharjah dormitories. The effect of storage (3 and 10 days) on the microbial population of kitchen sponges at room temperature (21 °C) was assessed. Enterobacteriaceae isolated from sponges were identified and their antibiotic resistance determined. RESULTS: Student responses revealed that kitchen sponges used to clean food contact surfaces were also used to clean the oven (32%), sink (26%), refrigerator (10%), and to clean spills on the floor (4%). Kitchen sponges contained high counts of mesophilic aerobic bacteria (7.9 log10/cm3), coliform (7.2 log10/cm3), Enterobacteriaceae (7.3 log10/cm3) and yeasts and molds (7.0 log10/cm3). After storage of the sponges at room temperature (21 °C) for 3 and 10 days, the number of mesophilic aerobic bacteria, coliform, Enterobacteriaceae and yeasts and molds decreased by 0.4 and 1.3 log10/cm3, 0.7 and 1.4 log10/cm3, 0.4 and 1.1 log10/cm3, and 0.6 and 1.3 log10/cm3, respectively. The most frequently isolated Enterobacteriaceae were Enterobacter cloacae (56%) and Klebsiella oxytoca (16%). All E. cloacae isolates were resistant to amoxicillin, cefalotin, cefoxitin and cefuroxime axetil. CONCLUSIONS: This study showed that students living in dormitories lacked good hygienic practices and were at increased risk of food poisoning. Kitchen sponges were highly contaminated with potentially pathogenic bacteria which could be transferred from the general kitchen environment to food contact surfaces and consequently lead to food contamination.

Inactivation of Salmonella spp. in tahini using plant essential oil extracts.

Tahini is a popular food product in the Middle East region and is used as a major ingredient in several ready-to-eat food products. Tahini and its products have been linked to foodborne illness outbreaks and product recalls worldwide as a result of Salmonella spp. contamination. The objectives of the current study were to investigate: i) the effectiveness of 10 plant essential oil extracts on the viability of Salmonella spp. using disc diffusion ii) the antimicrobial activity of the most effective oils against Salmonella spp. in commercial or 10% w/v hydrated tahini (tahini-based product model) stored at 37, 25 and 10 °C for 28 d and iii) the effect of the addition of essential oil extracts on the sensory acceptability of tahini and hydrated tahini. Among the tested essential oils, thyme (TO) and cinnamon oil (CO) showed the highest antimicrobial activity against tested Salmonella spp. at 37 and 10 °C using a disc diffusion assay method. In tahini, the addition of 2.0% CO reduced the numbers of Salmonella spp. by 2.87, 2.64 or 2.35 log10 CFU/ml at 37, 25 or 10 °C, respectively, by 28 d. However, the antimicrobial activity of CO was more pronounced at all storage temperatures in hydrated tahini where no viable cells were detected after 3 d storage at 25 and 37 °C, or after 7 d at 10 °C. However, at 25 and 37 °C, the antimicrobial activity of CO was more evident since no viable cells were detected after 14 d when 0.5% was used. The numbers of Salmonella spp. were reduced by 3.29, 3.03 or 2.17 log10 CFU/ml at 37, 25 or 10 °C, respectively, after 28 d when 2.0% TO was added to tahini. Salmonella spp. were not detected in the hydrated tahini treated with 2.0% TO after 28 d at 37 °C or 25 °C, while at 10 °C, the numbers of Salmonella spp. were not significantly reduced after 28 d in hydrated tahini compared to the initial numbers at zero time. Therefore, the addition of TO and CO could be used to preclude the post process contamination of tahini with foodborne pathogens, yet, the addition of TO and CO to tahini reduced its consumer acceptability compared untreated tahini.

Microbial safety of oily, low water activity food products: A review.

Oily, low water activity (OL aw) products including tahini (sesame seed paste), halva (tahini halva), peanut butter, and chocolate, have been recently linked to numerous foodborne illness outbreaks and recalls. This review discusses the ingredients used and processing of OL aw products with a view to provide greater understanding of the routes of their contamination with foodborne pathogens and factors influencing pathogen persistence in these foods. Adequate heat treatment during processing may eliminate bacterial pathogens from OL aw foods; however, post-processing contamination commonly occurs. Once these products are contaminated, their high fat and sugar content can enhance pathogen survival for long periods. The physiological basis and survival mechanisms used by pathogens in these products are comprehensively discussed here. Foodborne outbreaks and recalls linked to OL aw foods are summarized and it was observed that serotypes of Salmonella enterica were the predominant pathogens causing illnesses. Further, intervention strategies available to control foodborne pathogens such as thermal inactivation, use of natural antimicrobials, irradiation and hydrostatic pressure are assessed for their usefulness to achieve pathogen control and enhance the safety of OL aw foods. Sanitation, hygienic design of manufacturing facilities, good hygienic practices, and environmental monitoring of OL aw food industries were also discussed.

Factors affecting the viability of Staphylococcus aureus and production of enterotoxin during processing and storage of white-brined cheese.

Staphylococcus aureus is a major foodborne pathogen that causes severe disease in humans. It is commonly found in milk and dairy products, particularly in fresh brined cheese. Our aim was to investigate the behavior of Staph. aureus and enterotoxin production during the storage of white-brined cheese prepared with or without a starter culture and stored in a 10 or 15% NaCl brine at 10°C and 25°C for 28 d. NaCl concentration, water activity, pH, and number of Staph. aureus and lactic acid bacteria were determined in cheese and brine. Only 1 of 4 Staph. aureus strains (ATCC 439) was positive for enterotoxin production, and its production was detected in unsalted UHT milk, but not in salted milk or in any of the cheese treatments held at 37°C for 1, 3, or 7 d. Staphylococcus aureus grew in the cheese stored in both brines at 10°C and 25°C, regardless of the presence of a starter culture, although the latter significantly reduced Staph. aureus growth in cheese or its brine at 10°C. Staphylococcus aureus numbers were increased by 2.26 and 0.47 log10 cfu/g in cheese stored in 10 and 15% NaCl brine, respectively, in the presence of starter culture, and by 2.78 and 2.96 log10 cfu/g, respectively, in the absence of starter culture at 10°C. Nonetheless, the pathogen grew, but at a lower number in the brines. The salt concentration of cheese stored in 10% brine remained at approximately 5% during storage; however, in 15% brine, the salt concentration increased to almost 8% (wt/wt) by 28 d. The addition of a starter culture, high salt concentration, low temperature, and pH (∼5.2) had inhibitory effects on the growth of Staph. aureus. Moreover, lactic acid bacterial numbers increased considerably in cheese and brine by d 28. The use of starter cultures, salt (15%), and low storage temperature (10°C) reduced the growth of Staph. aureus, and salt may have prevented enterotoxin production in white-brined cheese.

Updates on understanding of probiotic lactic acid bacteria responses to environmental stresses and highlights on proteomic analyses.

Probiotics are defined as live microorganisms that improve the health of the host when administered in adequate quantities. Nonetheless, probiotics encounter extreme environmental conditions during food processing or along the gastrointestinal tract. This review discusses different environmental stresses that affect probiotics during food preparation, storage, and along the alimentary canal, including high temperature, low temperature, low and alkaline pH, oxidative stress, high hydrostatic pressure, osmotic pressure, and starvation. The understanding of how probiotics deal with environmental stress and thrive provides useful information to guide the selection of the strains with enhanced performance in specific situations, in food processing or during gastrointestinal transit. In most cases, multiple biological functions are affected upon exposure of the cell to environmental stress. Sensing of sublethal environmental stress can allow for adaptation processes to occur, which can include alterations in the expression of specific proteins.