Project description:Toxic elements have a negative impact on health, especially among infants and young children. Even low levels of exposure can impair the normal growth and development of children. In young children, all organs and metabolic processes are insufficiently developed, making them particularly vulnerable to the effects of toxic elements. The aim of this study is to estimate the concentration of toxic elements in products consumed by infants and young children. The health risk of young children due to consumption of ready-made products potentially contaminated with As (arsenic), Cd (cadmium), Hg (mercury), and Pb (lead) was also assessed. A total of 397 samples (dinners, porridges, mousses, snacks "for the handle", baby drinks, dairy) were analyzed for the content of toxic elements. Inductively coupled plasma mass spectrometry (ICP-MS) was used to assess As, Cd, and Pb concentration. The determination of Hg was performed by atomic absorption spectrometry (AAS). In order to estimate children's exposure to toxic elements, the content of indicators was also assessed: estimated daily intake (EDI), estimated weekly intake (EWI), provisional tolerable weekly intake (PTWI), provisional tolerable monthly intake (PTMI), the benchmark dose lower confidence limit (BMDL), target hazard quotient (THQ), hazard index (HI), and cancer risk (CR). The average content of As, Cd, Hg, and Pb for all ready-made products for children is: 1.411 ± 0.248 µg/kg, 2.077 ± 0.154 µg/kg, 3.161 ± 0.159 µg/kg, and 9.265 ± 0.443 µg/kg, respectively. The highest content As was found in wafer/crisps (84.71 µg/kg); in the case of Cd, dinners with fish (20.15 µg/kg); for Hg, dinners with poultry (37.25 µg/kg); and for Pb, fruit mousse (138.99 µg/kg). The results showed that 4.53% of the samples attempted to exceed Pb, and 1.5% exceeded levels of Hg. The highest value of THQ was made in the case of drinks, for Cd and Pb in mousses for children, and Hg for dairy products. The THQ, BMDL, and PTWI ratios were not exceeded. The analyzed ready-to-eat products for children aged 0.5-3 years may contain toxic elements, but most of them appear to be harmless to health.
Project description:We have previously shown that potentially pathogenic isolates of Staphylococcus epidermidis occur at high incidence in ready-to-eat food. Now, within 164 samples of ready-to-eat meat products we identified 32 S. epidermidis isolates. In 8 isolates we detected the genes encoding for staphylococcal enterotoxins, but in 7 S. epidermidis isolates these genes were not stable over passages. One isolate designated 4S was shown to stably harbour sec and sel genes. In the genome sequence of S. epidermidis 4S we identified 21,426-bp region flanked by direct-repeats, encompassing sec and sel genes, corresponding to the previously described composite staphylococcal pathogenicity island (SePI) in S. epidermidis FRI909. Alignment of S. epidermidis 4S and S. epidermidis FRI909 SePIs revealed 6 nucleotide mismatches located in 5 of the total of 29 ORFs. Genomic location of S. epidermidis 4S SePI was the same as in FRI909. S. epidermidis 4S is a single locus variant of ST561, being genetically different from FRI909. SECepi was secreted by S. epidermidis 4S to BHI broth ranging from 14 to almost 36?g/mL, to milk ranging from 6 to 9ng/mL, to beef meat juice from 2 to 3?g/mL and to pork meat juice from 1 to 2?g/mL after 24 and 48h of cultivation, respectively. We provide the first evidence that S. epidermidis occurring in food bears an element encoding an orthologue to Staphylococcus aureus SEC, and that SECepi can be produced in microbial broth, milk and meat juices. Regarding that only enterotoxins produced by S. aureus are officially tracked in food in EU, the ability to produce enterotoxin by S. epidermidis pose real risk for food safety.
Project description:Following the recent listeriosis outbreak in South Africa, this study was carried out to assess the safety level of various common ready-to-eat foods (RTE) obtained from supermarkets and grocery stores in major towns and cities within the Amathole, Chris Hani and Sarah Baartman Districts Municipalities, Eastern Cape Province, South Africa. A sum of 239 food samples was collected from these locations, and Listeria monocytogenes (Lm) was isolated in line with the recommended techniques by the International Organization for Standardization EN ISO 11290:2017 parts 1 and 2. Identification of the pathogen and detection of various associated virulence genes was done using Polymerase Chain Reaction (PCR) techniques. From the RTE food samples processed, Lm was detected in 107 (44.77%) of the samples. Russian sausage was the most contaminated (78.57%), followed by sliced polony (61.90%), muffins (58.33%), polony (52.63%), and pies (52.38%), while all vetkoek samples examined were negative for Lm. Although the prevalence of Lm in the food samples was very high, concentrations were generally < 100 CFU/g. Strains of Lm recovered from the RTE foods were predominantly epidemiological strains belonging to serotypes 1/2a, 1/2b and 4b. The prevalence of 10 virulence genes including the inlA, InlC, inlJ, plcA, hlyA, plcB, prfA, mpl, inlB, and actA were detected among Lm isolates. Most of the isolates (69.07%) demonstrated the potential for biofilm formation and were categorized as weak (14.95%), moderate (13.40%) and strong (40.72) biofilm formers. Furthermore, molecular typing revealed high levels of genetic diversity among Lm isolates. The findings of this investigation suggested that the presence of Lm in the RTE foods may constitute potential threats to the food sector and could pose public health hazards to consumers, particularly the high-risk group of the population. We, therefore, recommend that adequate food monitoring for safety and proper regulation enforcement in the food sector must be ensured to avoid any future listeriosis outbreak that could be linked to RTE foods in South Africa.
Project description:The contamination of ready to eat foods (RTE) products due to Listeria monocytogenes could compromise the products safety becoming a great risk for the consumers. The high presence of L. monocytogenes in RTE products has been described worldwide, but few data are available about these products from African countries. The aims of this study were to report the presence of L. monocytogenes in Zambian RTE products, providing genomic characterization and data on similarity with African circulating strains using whole genome sequencing (WGS). A total of 304 RTE products, produced by different Zambian manufacturers, were purchased at retail, from major supermarkets located in Lusaka, Zambia, comprising 130 dairy and 174 meat products. L. monocytogenes was detected only in 18 (10.3%) RTE meat products of the 174 samples tested. The MLST analysis grouped the 18 L. monocytogenes isolates in 7 clonal complexes (CCs): CC1 (n = 5), CC2 (n = 4), CC9 (n = 4), CC5 (n = 2), CC121 (n = 1), CC155 (n = 1), and CC3 (n = 1). According to the cgMLST results, several clusters were detected, in particular belonging to hyper-virulent clones CC1 and CC2. Regarding the virulence factors, a complete L. monocytogenes Pathogenicity Island 3 (LIPI-3) was present both in the CC1 and CC3, in addition to LIPI-1. Several resistance genes and mobile genetic elements were detected, including Stress Islands, the bcrABC cassette and Tn6188_qac transposon, plasmids and intact prophages. Despite being a first preliminary work with a limited number of samples and isolates, this study helped to increase existing knowledge on contaminated RTE products in Zambia, confirming the presence of hyper-virulent L. monocytogenes CCs, which could play an important role in human diseases, posing a public health concern for consumers.
Project description:Examination of Listeria monocytogenes prevalence among ready-to-eat foods in Japan revealed frequent (5.7 to 12.1%) contamination of minced tuna and fish roe products, and the isolates had the same virulence levels as clinical isolates in terms of invasion efficiency and infectivity in cell cultures and a murine infection model, respectively. Premature stop codons in inlA were infrequent (1 out of 39 isolates). Cell numbers of L. monocytogenes in minced tuna and salmon roe increased rapidly under inappropriate storage temperatures (from a most probable number [MPN] of 10(0) to 10(1)/g to an MPN of 10(3) to 10(4)/g over the course of 2 days at 10 degrees C). Thus, regulatory guidelines are needed for acceptable levels of L. monocytogenes in these foods.
Project description:Bacillus cereus is a major food-borne bacterial pathogen in the world, which can cause diarrhea and emetic syndrome. This study aimed to reveal the quantitative prevalence of B. cereus in ready-to-eat (RTE) rice products in Eastern China and to gain essential information on the characteristics of B. cereus isolates. A total of 91 out of the 1071 samples were positive for B. cereus. The contamination level of B. cereus in 0.5 % of RTE rice product samples outnumbered 103 CFU/g. The number of B. cereus attained 105-106 CFU/g in one sample. The distribution patterns of virulence genes in B. cereus isolates were identified. 84.6% of the B. cereus isolates had at least one enterotoxin or emetic toxin gene. The predominant pattern was XXV. 9.9% of isolates belonged to it and possessed one enterotoxin gene entFM. The occurrence rate of hblACD and nheABC was 36.3% and 47.3%, respectively. Antimicrobial susceptibility tests revealed a high resistance rate toward penicillin, and 23.1% of the isolates were multi-drug resistant. B. cereus isolates were genotyped by using ERIC-PCR. 89 genotypes were determined. The Hunter Gaston Discriminatory Index (HGDI) attained 0.9995. Relationships analysis revealed that Group A B. cereus isolates tended to carry hblA, hblC, hblD, nheA, nheB, and show resistance to penicillin/trimethoprim/sulfamethoxazole. This study was useful for updating the knowledge of the contamination status of B. cereus in RTE rice products in China.
Project description: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.
Project description:ObjectiveReady-to-eat (RTE) cereal is an important source of nutrients in the American diet. Recent regulatory changes to labelling requirements may impact the fortification of RTE cereal. We used an evidence-based approach to optimize the fortification of RTE cereal considering current dietary patterns and nutrition policy.DesignA US modelling study of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 2013-2014. The percentage of the population below the Estimated Average Requirement (EAR) and above the Upper Tolerable Intake Level (UL) was modelled under three scenarios: baseline, zero fortification and optimized fortification.SettingUSA.ParticipantsToddlers aged 1-3 years, n 559; children aged 4-12 years, n 1540; adolescents aged 13-18 years, n 992; and adults aged ≥19 years, n 576.ResultsComparing current with optimized fortification, nutrient/100 g RTE cereal decreased for vitamin A, thiamin, riboflavin, niacin, vitamin B6, folic acid, vitamin B12, Ca and Fe (by 2-82 %). The amount of vitamins C and D increased (by 13 and 50 %, respectively). Among RTE cereal eaters, these changes resulted in modest increases in the percentage of the population aged ≥1 year below the EAR (+0·5 to +11·5 percentage points). Decreases were observed in the percentage of the population above the UL.ConclusionsFortification of RTE cereal can be optimized to provide key nutrients and minimize the percentage of the population below the EAR and above the UL. Dietary intake modelling is useful to ensure that RTE cereal continues to help the population meet their nutrient needs.
Project description:Singapore is a multi-ethnic country with a great variety of traditional ethnic cuisines. In this modern society where there is an increasing prevalence of obesity, it is important to know the nutritional content and energy density of our foods. However, there have been little data on the nutritional content of our local foods. The energy density and nutrient content of 45 commonly consumed meals by three ethnic groups in Singapore (Chinese, Malay, and Indian) were assessed in this study. Chinese, Malay, and Indian cuisines had an average energy density of 661, 652, and 723 kJ/100 g, respectively. Moreover, the macronutrient content is different between the different ethnic groups. Compared to Chinese and Malay cuisines, Indian cuisine contained lower protein but higher fat and carbohydrate content (p = 0.03). From the mineral analysis of the ethnic foods, we found out that Chinese cuisines contain significantly higher sodium (average of 238 mg/100 g) than Malay cuisines (p = 0.006) and Indian cuisines (p = 0.03). Knowing the caloric density and nutrition content of local ethnic foods may aid hawkers and government officials in developing healthier options to tackle Singapore's obesity epidemic.
Project description:Listeria monocytogenes is a highly fatal foodborne causative agent that has been implicated in numerous outbreaks and related deaths of listeriosis in the world. In this study, six L. monocytogenes isolated from ready-to-eat (RTE) meat products were analysed using Whole Genome Sequencing (WGS) to identify virulence and resistance genes, prophage sequences, PCR-serogroups, and sequence types (STs). The WGS identified four different STs (ST1, ST121, ST204, and ST876) that belonged to serogroup 4b (lineage I) and 1/2a (lineage II). Core genome, and average nucleotide identity (ANI) phylogenetic analyses showed that the majority of strains from serogroup 4b (lineage I) clustered together. However, two isolates that belong to serogroup 1/2a (lineage II) grouped far from each other and the other strains. Examination of reference-guided scaffolds for the presence of prophages using the PHAge Search Tool Enhanced Release (PHASTER) software identified 24 diverse prophages, which were either intact or incomplete/questionable. The National Center for Biotechnology Information- Nucleotide Basic Local Alignment Search Tool (NCBI-BLASTn) revealed that Listeria monocytogenes strains in this study shared some known major virulence genes that are encoded in Listeria pathogenicity islands 1 and 3. In general, the resistance profiles for all the isolates were similar and encoded for multidrug, heavy metal, antibiotic, and sanitizer resistance genes. All the isolates in this study possessed genes that code for resistance to common food processing antiseptics such as Benzalkonium chloride.