Assessment of the Microbiological Quality and Effect of Public Health of Ready-to-Eat Salad Samples in Isparta

Salmonella spp. and Citrobacter spp. are among the microorganisms causing important foodborne outbreaks. In this study, it was tried to determine the presence and rate of Salmonella spp. and Citrobacter spp. in salad samples collected from certain regions of province of Isparta in Türkiye. A total of 50 salad samples were analyzed. Classical culture technique was used for microbiological analysis of salad samples. Suspected isolates obtained were identified using the VITEK-2 system. Although no negative visual changes were observed in the salad samples used in the study, it was determined that the number of Gram-negative microorganisms was very high and six salad samples were not suitable for public health. In 50 salad samples, 2% Salmonella and 4% Citrobacter freundii were detected. In addition, it was determined that the Salmonella strain isolated from the salad sample was resistant to three different antibiotics and Citrobacter was resistant to two different antibiotics. Salmonella spp. and Citrobacter spp. are considered very dangerous to public health because they are associated with foodborne outbreaks and can develop antibiotic resistance very quickly. Salad producers should try to reduce the possibility of microbial contamination by using different technologies.

Causal Associations of Modifiable Risk Factors With Migraine: Evidence From Mendelian Randomization Analysis

Background and objectives The exact etiology of migraine is unknown; however, it is likely a mixture of genetic and non-genetic factors including lifestyle variables like smoking and diet. This study aims to assess the causal effect of modifiable risk factors on the risk of migraine using two-sample Mendelian randomization. Materials and methods The study used publicly available genome-wide significant single nucleotide polymorphisms (SNPs). The study evaluated a diverse smoking exposure, encompassing age at smoking initiation, smoking intensity, and maternal smoking, alongside other pertinent risk factors, namely key dietary aspects, coffee consumption, BMI, and physical activity. Self-reported migraine was the outcome of the study. The genetic data for migraine were obtained from the FinnGen (Finland) and the UK Biobank (United Kingdom) cohorts. Results With sample sizes ranging from 64,949 to 632,802 for each risk factor collected from several consorts, the study included a total of 282 SNPs for all risk factors. The findings demonstrated that in the FinnGen consortium, genetically estimated dietary factors as well as BMI, were significantly associated with the risk of migraine (OR 0.765 per single unit of BMI, p = 0.011; OR 0.468 per one SD higher cheese intake, p = 0.012; OR 0.286 per one SD higher salad intake, p = 0.004, and 0.625 per one SD higher coffee consumption, p = 0.003, respectively). The results also showed that in the UK Biobank specifically, a genetically estimated history of maternal smoking was significantly associated with an elevated risk of migraine (OR=1.02, p=0.004). Conclusions The latest study implies a connection between maternal smoking and a heightened risk of migraines, whereas cheese intake, salad intake, coffee consumption, BMI, and physical activity are associated with a lower risk of migraine development.

An In Vitro Study on the Effects of Selected Natural Dietary Fiber from Salad Vegetables for Lowering Intestinal Glucose and Lipid Absorption

BACKGROUND

Salad vegetables are good sources of dietary fiber and are becoming increasingly popular among consumers. Therefore, these plants have the potential to be developed as functional foods.

OBJECTIVE

Using an in vitro model, this study investigated the physical properties and intestinal glucose and lipid absorption capacities of dry dietary fiber from vegetables typically consumed in salads (types of lettuce, including red oak, red coral, green oak, butterhead, and cos).

METHOD

Fiber was prepared from each type of lettuce using an enzymatic method and then characterized. Physical properties, including solubility and water-binding, swelling, cation-exchange, and oil-binding capacities, and antihyperglycemic and antihypercholesterolemic effects of fiber were investigated.

RESULTS

The hydration capacity of total dietary fiber and insoluble fiber from the majority of sources was significantly different from that of cellulose. Adsorption and diffusion of glucose were directly proportional to incubation time, and the diffusion rate was significantly lower in the treatments containing fiber compared to the cellulose control. Fiber from these vegetables also inhibited amylase and alpha-glucosidase activities. Moreover, fiber from all sources exhibited significantly higher sodium cholate and cholesterol-binding capacity compared to cellulose, and also retarded pancreatic cholesterol esterase activity in a concentration-dependent manner.

CONCLUSION

This study demonstrates that natural dietary fiber from salad vegetables can reduce glucose and lipid absorption and breakdown rates, thus preventing increases in postprandial blood glucose and cholesterol levels, which can be beneficial to human health.

Microbial risk assessment of ready-to-eat mixed vegetable salads from different restaurants of Bangladesh Agricultural University campus

Objective:

The study was aimed to analyze the microbiological quality of mixed vegetable salads and to understand the risk related with its consumption from different restaurants around Bangladesh Agricultural University campus in Mymensingh.

Materials and Methods:

Sixty (60) samples of mixed vegetable salads were taken from twelve (12) different restaurants in five different time points from each restaurant. In parallel, restaurant workers were asked for handling practices while the consumers were interviewed about their salad consumption pattern and whether they had experienced any health-related problems. Microbial risk assessment of Staphylococcus spp., Salmonella spp., and Escherichia coli was estimated by Monte Carlo simulation (10,000 iterations), an exponential model.

Results:

Aerobic plate count was ranged from 7.73 ± 0.61 to 9.04 ± 0.26 log cfu/gm, Staphylococcus spp. from 4.64 ± 0.61 to 6.42 ± 0.53 log cfu/gm, Salmonella spp. from 4.75 ± 0.08 to 5.27 ± 0.53 log cfu/gm, and E. coli from 4.98 ± 0.20 to 6.66 ± 0.80 log cfu/gm. From the survey, it was found that total consumers had 18% chances where the male had 13% and the female had 30% chances of being infected with salads. Again frequent, average, and occasional consumers had 31%, 13%, and 0% chances, respectively, of being infected with those salads. From the Monte Carlo simulation, the calculated mean annual risks of Staphylococcus spp., Salmonella spp., and E. coli infection for the three exposure scenarios were found to be about 100%.

Conclusion:

The study actually revealed the potential microbial contamination in mixed vegetable salads which may impact on food safety and human health. So, the findings suggest that following hygienic measures during processing and handling the microbiological quality of mixed vegetables salads can be improved.

Prevalence of Antibiotic Resistome in Ready-to-Eat Salad

Ready-to-eat salad harbors microorganisms that may carry various antibiotic resistance genes (ARGs). However, few studies have focused on the prevalence of ARGs on salad, thus underestimating the risk of ARGs transferring from salad to consumers. In this small-scale study, high-throughput quantitative PCR was used to explore the presence, prevalence and abundance of ARGs associated with serving salad sourced from two restaurant types, fast-food chain and independent casual dining. A total of 156 unique ARGs and nine mobile genetic elements (MGEs) were detected on the salad items assessed. The abundance of ARGs and MGEs were significantly higher in independent casual dining than fast-food chain restaurants. Absolute copies of ARGs in salad were 1.34 × 10⁷ to 2.71 × 10⁸ and 1.90 × 10⁸ to 4.87 × 10⁸ copies per g salad in fast-food and casual dining restaurants, respectively. Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the dominant bacterial phyla detected from salad samples. Pseudomonas, Acinetobacter, Exiguobacterium, Weissella, Enterobacter, Leuconostoc, Pantoea, Serratia, Erwinia, and Ewingella were the 10 most dominant bacterial genera found in salad samples. A significant positive correlation between ARGs and MGEs was detected. These results integrate knowledge about the ARGs in ready-to-eat salad and highlight the potential impact of ARGs transfer to consumers.

NMR study of fresh cut salads: Influence of temperature and storage time on leaf structure and water distribution in escarole

Consumption of fresh-cut vegetables has rapidly increased over the past decades. Among salads, escarole is one of the most popular varieties. Specific packaging limits gas exchange and consequently water loss and bacterial respiration, increasing the shelf life of salads. Although the major cause of quality loss for minimally processed salads is the leaf textural changes, this aspect has rarely been investigated. Therefore, investigating structural changes of leaves during storage is important in order to understand and minimize quality loss of salads. In this study, we focused on the impact of storage duration and temperature on the escarole leaf structure. The complex leaf structure was investigated by relaxation NMR, via transverse relaxation times, which allows the specific description of vacuolar water compartment of the cell. The storage duration (maximum 12 days) and temperatures (4°C, 7°C, 10°C, and 12°C) have been chosen in order to represent the conditions registered in factory. The results showed that the temperature did not have significant impact on the salad structure during the first week. During the second week, changes in the water distribution and changes in the relaxation time T2 have been observed. The changes in transverse relaxation times associated with vacuolar water are related to lost of cell membrane and wall integrity. The NMR results confirmed the effect of storage temperature on the degradation process of the cell before visual detection of the salad leaf degradation. The present study confirmed the sensibility of NMR relaxometry for monitoring water changes in the leaf.

Viral outbreaks linked to fresh produce consumption: a systematic review

AIMS

Α systematic review to investigate fresh produce-borne viral outbreaks, to record the outbreak distribution worldwide and to analyse the implication of different types of fresh produce and viral types as well.

METHODS AND RESULTS

Four databases (PubMed/Medline, Scopus, Eurosurveillance Journal and Spingerlink electronic journal) and a global electronic reporting system (ProMED-mail) were searched up to 2016. One hundred and fifty-two viral outbreaks linked to fresh produce consumption were identified. The majority of the reported outbreaks was reported in Europe, followed by North America, Asia, Australia, Africa and South America. A great number of the outbreaks was recorded in Denmark and Finland. The most common viral pathogens were norovirus (48·7%) and hepatitis A virus (46·1%). The most frequent type of fresh produce involved was frozen raspberries (23·7%). Differences in the reporting of outbreaks were recorded between the scientific literature and ProMED.

CONCLUSIONS

The number of reported illnesses linked to fresh produce has increased in several countries. Consumption of contaminated fresh produce represents a risk to public health in both developed and developing countries, but the impact will be disproportionate and likely to compound existing health disparities. For this reason, all countries should systematically collate and report such data through a disease surveillance system, in order to adopt risk management practices for reducing the likelihood of contamination.

Efficacy Evaluation of Control Measures on the Reduction of Staphylococcus aureus in Salad and Bacillus cereus in Fried Rice Served at Restaurants

The objective of this study was to assess the effect of washing on Staphylococcus aureus reduction in salads and the effect of reheating on Bacillus cereus vegetative cells and spores reduction in fried rice at restaurants using the stochastic food safety objective (FSO) tool. The leaf vegetable was inoculated with S. aureus and washed with tap water, 100 ppm of NaClO, or 30 ppm of slightly acidic electrolyzed water (SAEW) for either 60 s or 5 min. The washing effect of 30 ppm SAEW was greater than that of 100 ppm NaClO. Based on the FSO concept, washing leaf vegetables with 30 ppm SAEW for 5 min was the most efficient control measure for S. aureus in salads. In addition, the salad should be consumed within 4 h at 25°C and 2 h at 35°C after 5 min of washing with 100 ppm NaClO or 30 ppm SAEW. The fried rice was first inoculated with B. cereus vegetative cells or spores and was then reheated in a frying pan at medium (internal temperature of fried rice: 69.2°C-78.8°C) or high heat (internal temperature of fried rice:103.8°C-121.4°C) or in a microwave oven (internal temperature of fried rice:86.3°C-90.6°C) for 3 or 4 min. Based on the FSO, reheating rice in a microwave oven was the most efficient control measure for B. cereus vegetative cells and spores in fried rice. The holding time for fried rice can be extended up to 6 h at 25°C, 3 h at 35°C, and 2 h at 45°C with reheating. Microbiological hazards in salads and fried rice can be controlled by washing with a sanitizer and reheating, respectively and then by controlling of holding temperature before being served at restaurants.

A food-borne outbreak of gastroenteritis due to genotype G1P[8] rotavirus among adolescents in Japan

Six high school students in Tochigi prefecture, Japan, developed gastroenteritis after eating at a pork cutlet shop. Molecular epidemiologic analyses showed that the causative agent was genotype G1P[8] rotavirus (RV), this being detected in stool samples from both the patients and the asymptomatic food handlers. The detected RV strains were closely related genetically. The only uncooked food that all victims had eaten was raw sliced cabbage. These findings results suggest that uncooked foods contaminated with RV may be sources of infectious gastroenteritis in adolescents.

Isolation of toxigenic Clostridium difficile from ready-to-eat salads by multiplex polymerase chain reaction in Isfahan, Iran

Background:

Since 2003, the incidence of community associated Clostridium difficile infection (CA-CDI) has increased; different types of food have been supposed to be the vectors of C. difficile strains. The purpose of this study is to investigate the occurrence of C. difficile strains in ready-to-eat salads distributed in food services.

Materials and Methods:

A total of 106 ready-made salad specimens were sampled from different restaurants and food services located in Isfahan, in the center of Iran. Positive isolates of C. difficile were identified and confirmed for the existence of three genes including tpi, tcdA and tcdB by multiplex PCR.

Results:

A total of six (5.66%) samples were positive for C. difficile strains. Of which, one strain (16.6%) was positive for A and B toxins.

Conclusion:

The existence of toxigenic C. difficile in ready-made salads could be a caution for public health. Further investigation is required to assess the relationship between the isolated strains in our study and those from diarrheic patients through molecular typing.

Clostridium difficile in ready-to-eat salads, Scotland

Of 40 ready-to-eat salads, 3 (7.5%) were positive for Clostridium difficile by PCR. Two isolates were PCR ribotype 017 (toxin A-, B+), and 1 was PCR ribotype 001. Isolates were susceptible to vancomycin and metronidazole but variably resistant to other antimicrobial drugs. Ready-to-eat salads may be potential sources for virulent C. difficile.