Review of Quantitative Microbial Risk Assessment in Poultry Meat: The Central Position of Consumer Behavior

Health risk assessment of Staphylococcus aureus and Salmonella from the consumption of street foods in Ethiopia

INTRODUCTION

Due to inadequate hygienic practices and improper handling, street foods may become contaminated, posing a significant risk for various foodborne diseases. This study aimed to determine the health risks to consumers from consuming street foods contaminated with Staphylococcus aureus and Salmonella.

METHOD

A cross-sectional study design was used from December 2022 to February 2023 on the street foods of Addis Ababa, Hawassa, Dire Dawa, and Jimma towns. A total of 525 street foods were taken from 175 street food vending stalls. A stratified sampling technique was used to select vending stalls. A questionnaire was used to collect the data which were analyzed via SPSS-25. Food samples were analyzed at the Ethiopian Public Health Institute food microbiology laboratory using the standard microbiological methods used for the isolation, enumeration, and identification of bacteria. A quantitative microbial risk assessment was used to assess and determine the risk of infection using a deterministic approach.

RESULT

The frequent, average, and occasional consumers of street foods were 26.9%, 52.6%, and 20.5% respectively. The prevalence of Staphylococcus aureus was 43.4% whereas 25.7% for Salmonella species. The risk of infection from S. aureus was higher than Salmonella. The mean annual risk of S aureus infection of consumers was 100%, 99%, and 93% for frequent, average, and occasional consumers respectively. A total of 32.6% of the sampled foods had greater than 104 CFU/g a colony count of Staphylococcus aureus whereas in 25.7% of the samples Salmonella exceeded the safety standards and made the food unfit for consumption.

CONCLUSION

The results highlighted the significant risk of infection with Staphylococcus aureus and Salmonella in Ethiopian street foods, and revealed that frequent consumption of street foods was associated with a high risk of infection. This urges improved hygiene practices to mitigate hazards and protect public health.

CircFBLN2 regulates duck myoblast proliferation and differentiation through miR-22-5p and MEF2C interaction

The growth and development of duck skeletal muscle significantly affect duck meat production, making it essential to understand the molecular mechanisms underlying these processes. Circular RNAs (circRNAs) and microRNAs (miRNAs) are identified in many species and play essential roles in the regulation of myogenic processes; however, research on circRNAs and miRNAs involved in the duck skeletal muscle development is limited. In prior whole-transcriptome RNA sequencing study, we identified differential expression of miR-22-5p and the novel circular RNA circFBLN2, which arises from the second exon of the FBLN2 gene, in duck primary myoblasts (DPMs). In this study, we confirmed the circular structure of circFBLN2 and explored its expression patterns and functional implications in myogenesis. To elucidate the function of circFBLN2 in the myogenic processes of duck, we conducted experiments involving both the silencing and overexpression of circFBLN2 in DPMs. Our findings indicated that circFBLN2 inhibits DPM proliferation while promoting their differentiation. Conversely, when miR-22-5p was silenced and overexpressed, it exhibited opposing effects by promoting the proliferation of DPMs and inhibiting their differentiation. These results suggest a complex dynamic interplay between circFBLN2 and miR-22-5p in the regulation of DPMs proliferation and differentiation. Additionally, our results revealed that both circFBLN2 and myocyte enhancer factor 2 C (MEF2C) act as sponges for miR-22-5p, as demonstrated by binding predictions and dual-luciferase reporter assays. These results offer novel perspectives on the regulatory pathways underlying the duck embryonic skeletal muscle development, underscoring the pivotal function of circFBLN2 in the regulation of miR-22-5p expression. This research deepens our comprehension of the molecular underpinnings of avian myogenesis, potentially paving the way for more effective approaches to bolster growth and development of livestock.

Cultivated meat microbiological safety considerations and practices

Cultivated meat, produced using cell culture technology, is an alternative to conventional meat production that avoids the risks from enteric pathogens associated with animal slaughter and processing. Cultivated meat therefore has significant theoretical microbiological safety advantages, though limited information is available to validate this. This review discusses sources and vectors of microbial contamination throughout cultivated meat production, introduces industry survey data to evaluate current industry practices for monitoring and mitigating these hazards, and highlights future research needs. Industry survey respondents reported an average microbiological contamination batch failure rate of 11.2%. The most common vectors were related to personnel, equipment, and the production environment, while the most commonly reported type of microbiological contaminant was bacteria. These will likely remain prominent vectors and source organisms in commercial-scale production but can be addressed by a modified combination of existing commercial food and biopharmaceutical production safety systems such as Hazard Analysis and Critical Control Points (HACCP), Good Manufacturing Practices (GMP), and Good Cell Culture Practice (GCCP). As the sector matures and embeds these and other safety management systems, microbiological contamination issues should be surmountable. Data are also included to investigate whether the limited microbiome of cultivated products poses a novel food safety risk. However, further studies are needed to assess the growth potential of microorganisms in different cultivated meat products, taking into account factors such as their composition, pH, water activity, and background microflora.

Exploring Gene Expression and Alternative Splicing in Duck Embryonic Myoblasts via Full-Length Transcriptome Sequencing

The duck industry is vital for supplying high-quality protein, making research into the development of duck skeletal muscle critical for improving meat and egg production. In this study, we leveraged Oxford Nanopore Technologies (ONT) sequencing to perform full-length transcriptome sequencing of myoblasts harvested from the leg muscles of duck embryos at embryonic day 13 (E13), specifically examining both the proliferative (GM) and differentiation (DM) phases. Our analysis identified a total of 5797 novel transcripts along with 2332 long non-coding RNAs (lncRNAs), revealing substantial changes in gene expression linked to muscle development. We detected 3653 differentially expressed genes and 2246 instances of alternative splicing, with key genes involved in essential pathways, such as ECM-receptor interaction and Notch signaling, prominently featured. Additionally, we constructed a protein-protein interaction network that highlighted critical regulators-MYOM3, MYL2, MYL1, TNNI2, and ACTN2-associated with the processes of proliferation and differentiation in myoblasts. This extensive transcriptomic investigation not only sheds light on the intricate molecular mechanisms driving skeletal muscle development in ducks but also provides significant insights for future breeding strategies aimed at enhancing the efficiency of duck production. The results emphasize the efficacy of ONT sequencing in uncovering complex regulatory networks within avian species, ultimately contributing to progress in animal husbandry.

Microbial Food Safety of Sous Vide Cooking Processes of Chicken and Eggs

Sous vide cooking implies cooking foods, packed under vacuum conditions, at controlled temperatures (<80 °C). Although this method opens a new window of culinary possibilities, it also involves a series of risks, mainly microbiologically related, that must be assessed. The aim of this work was to evaluate the effectiveness of SV processes to inactivate three important foodborne pathogens (Campylobacter, Salmonella, and Clostridium spores) in chicken breast and eggs (omelet). For this purpose, two levels of inoculation (102 and 106 CFU/g), two different recipes, and two distinct treatments (with and without storage) for each food were studied. After treatments and storage, the corresponding microbiological counts were performed with standard methods. Average inactivation rates observed were 1.70, 4.82, and 4.34 log for Clostridium spores, Campylobacter, and Salmonella, respectively. No significant differences in microbial inactivation were perceived between the different recipes (food composition) or treatments, except for Clostridium spores, which showed a higher inactivation rate (2.30 log) when samples were stored. In general, preliminary results showed that, although appropriate levels of inactivation are reached for vegetative pathogenic cells, in some cases (spores in breast and Salmonella in eggs), the remaining microbiological risks should be considered and further studied, especially if long-term storage is planned.

Airborne concentrations of bacteria and mold in Korean public-use facilities: measurement, systematic review, meta-analysis, and probabilistic human inhalation risk assessment

Bioaerosols adversely affect human health posing risk to users of public facilities in Korea. Between October 2021 and May 2022, airborne bacteria and mold were measured in 1,243 public-use facilities across 23 categories. A systematic review and meta-analysis were performed on these and other studies from June 2004 to May 2021, and the non-carcinogenic risks to humans were assessed using Monte Carlo simulations. For bacteria, the maximum 95th percentile concentration was 584.4 cfu/m3 and 1384.8 cfu/m3 for mold. The heterogeneity statistic I2 was over 50% in all facilities, and for subway station bacteria, there was a significant difference according to the measurement method. The 95th percentile of hazard by population group was 8.83 × 10-2 to 3.42 × 10-1 for bacteria, and 1.31 × 10-1 to 3.55 × 10-1 for mold. The probability of a hazard quotient exceeding 1 for some population groups was derived from exposure to bacteria and mold in the air resulting from the use of all public facilities. The most powerful explanatory factor for risk was exposure time to the facility, both within (up to 0.922 for bacteria and up to 0.960 for mold) and between populations (up to 0.543 for bacteria and 0.483 for mold). This study identified populations at risk of bioaerosol exposure in Korean public-use facilities and estimated the influencing factors, highlighting the need for comprehensive improvement in bioaerosol control in public-use facilities.

Cross-contamination in the kitchen: A model for quantitative microbiological risk assessment

A quantitative microbiological risk assessment model for the cross-contamination transmission route in the kitchen (KCC) is presented. Bacteria are transmitted from contaminated (chicken) meat to hands, kitchen utensils, and other surfaces, subsequently contaminating a salad. The model aims to estimate the fraction of bacteria on the meat that is ingested due to cross-contamination, determine the importance of the different transmission routes, and assess the effect of scenarios (interventions) on the fraction ingested. The cross-contamination routes defined, bacterial source-to-recipient transfer fractions as available and derived from literature, and important characteristics (e.g., washing in cold water vs. hot water with soap) shaped the KCC model. With this model, 32 scenarios of an eight-step preparation of a "meat and salad" meal in a domestic kitchen were stochastically simulated. The "cutting board-salad" route proved dominant and the salad plays a major role in the final exposure. A realistic scenario (washing hands, cutting board, and knife with cold water after cutting the meat) estimates that a mean fraction of 3.2E - 3 of the bacteria on the meat is ingested. In the case of "hand washing with hot water and soap" and "cutting board and knife replacement," the mean fraction ingested is 3.6E - 6. For a subsequent meal, where the contaminated sources were kitchen fomites, the estimated mean fraction is 4.3E - 4. In case of hamburger, part of the bacteria is unavailable for cross-contamination, resulting in a mean fraction ingested of about 5.4E - 5. The role of the dishcloth in cross-contamination transmission proved to be minor.

Poultry Food Assess Risk Model for Salmonella and Chicken Gizzards: III. Dose Consumed Step

The Dose Consumed step of the Poultry Food Assess Risk Model (PFARM) for Salmonella and chicken gizzards was presented and compared to the Exposure Assessment step of Quantitative Microbial Risk Assessment (QMRA). The specific objectives were 1) to demonstrate the dose consumed step of PFARM for Salmonella and chicken gizzards; 2) to compare Salmonella dose consumed from cooked chicken gizzards to that from cross-contaminated and temperature-abused lettuce; 3) to determine if Salmonella dose consumed changed over time in a production chain; and 4) to compare PFARM and QMRA predictions of Salmonella dose consumed. The PFARM and QMRA were developed in an Excel notebook and simulated with @Risk. Salmonella prevalence and number data (P = 100) for chicken gizzards (56 g) and scenario analysis were used to address objectives 1, 2, and 4, whereas running windows of 60 consecutive chicken gizzard samples and scenario analysis were used to address objective 3. A lot size of 1,000 kg of chicken gizzards was simulated. Mean portion size was 168 g resulting in the simulation of 5,952 meals per lot. Of these, 3.69 ± 0.32% and 0.49 ± 0.07% (mean ± SD) resulted in Salmonella dose consumed of ≥1 per meal from cooked chicken gizzards and lettuce, respectively. However, the total Salmonella dose consumed per lot from cooked chicken gizzards (272 ± 27) was less (P ≤ 0.05) than from lettuce (6,050 ± 4,929) because of a few highly contaminated (>310 Salmonella) lettuce portions at consumption. Over time in the production chain, Salmonella prevalence and total dose consumed per lot changed (P ≤ 0.05) but the patterns differed. The QMRA predicted higher (P ≤ 0.05) Salmonella dose consumed per meal than PFARM. In part, this was because QMRA only simulated contaminated grams, whereas PFARM simulated contaminated and non-contaminated meals. However, other factors, which are discussed, also contributed to the overestimation of Salmonella dose consumed by QMRA.

Whole-Transcriptome RNA Sequencing Uncovers the Global Expression Changes and RNA Regulatory Networks in Duck Embryonic Myogenesis

Duck meat is pivotal in providing high-quality protein for human nutrition, underscoring the importance of studying duck myogenesis. The regulatory mechanisms governing duck myogenesis involve both coding and non-coding RNAs, yet their specific expression patterns and molecular mechanisms remain elusive. To address this knowledge gap, we performed expression profiling analyses of mRNAs, lncRNAs, circRNAs, and miRNAs involved in duck myogenesis using whole-transcriptome RNA-seq. Our analysis identified 1733 differentially expressed (DE)-mRNAs, 1116 DE-lncRNAs, 54 DE-circRNAs, and 174 DE-miRNAs when comparing myoblasts and myotubes. A GO analysis highlighted the enrichment of DE molecules in the extracellular region, protein binding, and exocyst. A KEGG analysis pinpointed pathways related to ferroptosis, PPAR signaling, nitrogen metabolism, cell cycle, cardiac muscle contraction, glycerolipid metabolism, and actin cytoskeleton. A total of 51 trans-acting lncRNAs, including ENSAPLT00020002101 and ENSAPLT00020012069, were predicted to participate in regulating myoblast proliferation and differentiation. Based on the ceRNAs, we constructed lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA ceRNA networks involving five miRNAs (miR-129-5p, miR-133a-5p, miR-22-3p, miR-27b-3p, and let-7b-5p) that are relevant to myogenesis. Furthermore, the GO and KEGG analyses of the DE-mRNAs within the ceRNA network underscored the significant enrichment of the glycerolipid metabolism pathway. We identified five different DE-mRNAs, specifically ENSAPLG00020001677, ENSAPLG00020002183, ENSAPLG00020005019, ENSAPLG00020010497, and ENSAPLG00020017682, as potential target genes that are crucial for myogenesis in the context of glycerolipid metabolism. These five mRNAs are integral to ceRNA networks, with miR-107_R-2 and miR-1260 emerging as key regulators. In summary, this study provides a valuable resource elucidating the intricate interplay of mRNA-lncRNA-circRNA-miRNA in duck myogenesis, shedding light on the molecular mechanisms that govern this critical biological process.

Distribution-based maximum likelihood estimation methods are preferred for estimating Salmonella concentration in chicken when contamination data are highly left-censored

Salmonella is a common chicken-borne pathogen that causes human infections. Data below the detection limit, referred to as left-censored data, are frequently encountered in the detection of pathogens. The approach of handling the censored data was regarded to affect the estimation accuracy of microbial concentration. In this study, a set of Salmonella contamination data was collected from chilled chicken samples using the most probable number (MPN) method, which consisted of 90.42% (217/240) non-detect values. Two simulated datasets with fixed censoring degrees of 73.60% and 90.00% were generated based on the real-sampling Salmonella dataset for comparison. Three methodologies were applied for handling left-censored data: (i) substitution with different alternatives, (ii) the distribution-based maximum likelihood estimation (MLE) method, and (iii) the multiple imputation (MI) method. For each dataset, the negative binomial (NB) distribution-based MLE and zero-modified NB distribution-based MLE were preferable for highly censored data and resulted in the least root mean square error (RMSE). Replacing the censored data with half the limit of quantification was the next best method. The mean concentration of Salmonella monitoring data estimated by the NB-MLE and zero-modified NB-MLE methods was 0.68 MPN/g. This study provided an available statistical method for handling bacterial highly left-censored data.

Quantitative microbiological risk assessment of nontyphoidal Salmonella in ground pork in households in Chengdu, China

Foodborne disease caused by nontyphoidal Salmonella (NTS) is one of the most important food safety issues worldwide. The objectives of this study were to carry out microbial monitoring on the prevalence of NTS in commercial ground pork, investigate consumption patterns, and conduct a quantitative microbiological risk assessment (QMRA) that considers cross-contamination to determine the risk caused by consuming ground pork and ready-to-eat food contaminated during food handling in the kitchen in Chengdu, China. The food pathway of ground pork was simplified and assumed to be several units according to the actual situation and our survey data, which were collected from our research or references and substituted into the QMRA model for simulation. The results showed that the prevalence of NTS in ground pork purchased in Chengdu was 69.64% (95% confidence interval [CI], 60.2-78.0), with a mean contamination level of -0.164 log CFU/g. After general cooking, NTS in ground pork could be eliminated (contamination level of zero). The estimated probability of causing salmonellosis per day was 9.43E-06 (95% CI: 8.82E-06-1.00E-05), while the estimated salmonellosis cases per million people per year were 3442 (95% CI: 3218-3666). According to the sensitivity analysis, the occurrence of cross-contamination was the most important factor affecting the probability of salmonellosis. To reduce the risk of salmonellosis caused by NTS through ground pork consumption, reasonable hygiene prevention and control measures should be adopted during food preparation to reduce cross-contamination. This study provides valuable information for household cooking and food safety management in China.

Profiling Analysis of N6-Methyladenosine mRNA Methylation Reveals Differential m6A Patterns during the Embryonic Skeletal Muscle Development of Ducks

Simple Summary

Recent studies show that N6-methyladenosine (m6A) modification, the most common RNA chemical modification, influences the modification, processing, transport, and translation of RNA. N6-methyladenosine is an epigenetic modification that influences skeletal myogenesis and skeletal muscle development. However, the N6-methyladenosine modification profile and its function during poultry muscle development is unclear, and there is only one report about m6A modification in ducks, which focuses on duck hepatitis A virus infection. Here, we compared the m6A modification profiles between E13 (embryonic day 13) and E19 (embryonic day 19) in duck breast muscle differentiation using MeRIP-seq, and evaluated the expression profile of the methyl transferase METTL14 and its cofactors during breast muscle development. This is the first study of N6-methyladenosine modification patterns in duck muscle tissue. The current study not only elucidates the regulation mechanisms of duck skeletal muscle development, but also lays the groundwork for studying the role of RNA modification in poultry muscle development.

Abstract

N6-Methyladenosine is a reversible epigenetic modification that influences muscle development. However, the m6A modification profile during poultry skeletal muscle development is poorly understood. Here, we utilized m6A-specific methylated RNA immunoprecipitation sequencing to identify m6A sites during two stages of breast muscle development in ducks: embryonic days 13 (E13) and E19. MeRIP-seq detected 19,024 and 18,081 m6A peaks in the E13 and E19 groups, respectively. Similarly to m6A distribution in mammalian transcripts, our results revealed GGACU as the main m6A motif in duck breast muscle; they also revealed that m6A peaks are mainly enriched near the stop codons. In addition, motif sequence analysis and gene expression analysis demonstrated that m6A modification in duck embryo skeletal muscles may be mediated by the methyltransferase-like 14. GO and KEGG analysis showed that m6A peaks containing genes at E19 were mainly enriched in muscle-differentiation- and muscle-growth-related pathways, whereas m6A peaks containing genes in E13 were mainly enriched in embryonic development and cell proliferation pathways. Combined analysis of MeRIP-seq and RNA-seq showed that the mRNA expression may be affected by m6A modification. Moreover, qRT-PCR analysis of the expression of METTL14 and its cofactors (WTAP, ZC3H13, RBM15 and VIRMA) during duck embryonic skeletal muscle development in breast and leg muscle samples revealed a significant downward trend as the developmental age progressed. Our results demonstrated that m6A mRNA methylation modifications control muscle development in ducks. This is the first study of m6A modification patterns in duck muscle tissue development, and it lays the foundation for the study of the effects of RNA modification on poultry skeletal muscle development.

Salmonella spp. in Chicken: Prevalence, Antimicrobial Resistance, and Detection Methods

Multidrug-resistant Salmonella spp. is one of the leading causes of worldwide foodborne disease outbreaks. Animal-derived foods, particularly chicken and poultry products, are the most likely source of Salmonella transmission to humans. The increasing demand for chicken meat has raised a global food safety issue. This review aims to determine the prevalence and antimicrobial resistance of Salmonella spp. in chickens from various countries in Asia. The methods for detecting Salmonella will also be discussed in this review. The prevalence of Salmonella spp. in chicken and poultry products is lower in developed countries than in developing countries. In addition, the incidence of Salmonella spp. in chicken and poultry products from fresh markets is higher than those from supermarkets. Furthermore, this review also reported the presence of multidrug-resistant Salmonella strains in various Asian countries. Rapid Salmonella detection based on immunological assays, molecular-based assays, and biosensors can provide more accurate results with high sensitivity and specificity. These methods also require a shorter time than the cultural-based Salmonella detection method. The use of suitable detection methods to determine the presence of Salmonella spp. in chicken and poultry products is important to ensure food safety.

A scoping review of factors potentially linked with antimicrobial-resistant bacteria from turkeys (iAM.AMR Project)

Antimicrobial resistance (AMR) is a complex problem that is a threat to global public health. Consumption of turkey meat may be an important source of foodborne exposure to resistant bacteria; recent outbreaks of multi-drug-resistant Salmonella Reading in Canada and the USA have implicated raw turkey products. To better understand the epidemiology of AMR in farmed turkey production, a scoping review was conducted. The objectives were to identify (1) modifiable factors potentially associated with antimicrobial-resistant Campylobacter, Enterococcus, Escherichia coli and Salmonella enterica along the farm-to-fork pathway in turkeys, and (2) data gaps with respect to factors potentially associated with AMR and Canadian commercial turkey production. A comprehensive search of the peer-reviewed literature was conducted in 2019 and updated in 2021. Thirteen references were included, reporting 36 factors. Antimicrobial use factors and their potential associations with AMR were most frequently reported (n = 15 factors; 42%), followed by biosecurity (n = 11; 31%) and management practices (n = 10; 28%). This review revealed important data gaps; no factors pertaining to S. enterica or to stages other than the farm (e.g. abattoir, retail) were identified, and only one Canadian reference was identified. These findings will inform priorities for future research and surveillance regarding turkeys and AMR.

Growth of Listeria monocytogenes in Partially Cooked Battered Chicken Nuggets as a Function of Storage Temperature

Battered poultry products may be wrongly regarded and treated by consumers as ready-to-eat and, as such, be implicated in foodborne disease outbreaks. This study aimed at the quantitative description of the growth behavior of Listeria monocytogenes in fresh, partially cooked (non-ready-to-eat) battered chicken nuggets as function of temperature. Commercially prepared chicken breast nuggets were inoculated with L. monocytogenes and stored at different isothermal conditions (4, 8, 12, and 16 °C). The pathogen’s growth behavior was characterized via a two-step predictive modelling approach: estimation of growth kinetic parameters using a primary model, and description of the effect of temperature on the estimated maximum specific growth rate (μ_max) using a secondary model. Model evaluation was undertaken using independent growth data under both constant and dynamic temperature conditions. According to the findings of this study, L. monocytogenes may proliferate in battered chicken nuggets in the course of their shelf life to levels potentially hazardous for susceptible population groups, even under well-controlled refrigerated storage conditions. Model evaluation demonstrated a satisfactory performance, where the estimated bias factor (B_f) was 0.92 and 1.08 under constant and dynamic temperature conditions, respectively, while the accuracy factor (A_f) value was 1.08, in both cases. The collected data should be useful in model development and quantitative microbiological risk assessment in battered poultry products.