Modeling the Reduction of Salmonella spp. on Chicken Breasts and Wingettes during Scalding for QMRA of the Poultry Supply Chain in China

Bacterial contamination of chicken meat in slaughterhouses and the associated risk factors: A nationwide study in Thailand

Slaughterhouses are a key source of bacterial contamination in poultry meat and products, which is a major health and economic concern for several public authorities. This study aimed to quantify the non-compliance of bacterial contamination on chicken meat sampled from slaughterhouses and identify risk factors associated with the contamination. A questionnaire survey of 569 chicken slaughterhouses was undertaken and 1,707 meat samples were collected to determine the level of bacterial contamination. The proportion of the non-compliance associated with aerobic plate count [APC] (24.6%), Staphylococcus aureus (6.3%), Enterococcus spp. (24.7%), coliforms (13.5%), Escherichia coli (33.3%), and Salmonella spp. (33.4%) based on the livestock authorities' criteria was determined. Our results highlighted that the scalding process without scalding water temperature control or improper scalding increased the risk of APC (odds ratio, OR = 4.84, 95% CI: 2.72-8.61), S. aureus (OR = 2.68, 95% CI: 1.29-5.55), Enterococcus spp. (OR = 3.38, 95% CI: 2.01-5.69), coliforms (OR = 3.01, 95% CI: 1.47-6.15), and E. coli (OR = 2.69, 95% CI: 1.58-4.56) contamination on meat samples. Meat from eviscerated carcasses was more likely to be non-compliance due to contamination by E. coli (OR = 1.96, 95% CI: 1.14-3.38). Furthermore, open or semi-closed system slaughterhouses (OR = 1.79, 95% CI: 1.23-2.60) and lack of equipment for specific slaughtering areas (OR = 1.65, 95% CI: 1.04-2.61) increased the likelihood of Salmonella spp. occurrence. This is the first study of factors influencing the non-compliance of meat samples across Thailand. Authorities can use the study findings to enhance food safety strategies at the national level.

Using Risk–Benefit Analysis to Control Salmonella in Chicken Meat

We have created a risk–benefit analysis (RBA) model to assist in food safety decision-making by analyzing Salmonella control in Brazilian chicken meat. First, we described the issues in a risk profile and used a 5×5 matrix to rank the risks associated with Salmonella. We then classified the magnitude of benefits and costs of control measures using another matrix. Finally, we verified the beneficial effects of recommended control measures using Quantitative Microbiological Risk Assessment (QMRA). The RBA classified Salmonella contamination as risk 6, indicating that control measures should be taken in the short and medium terms. It also recommended the adoption of biosecurity measures on farms to reduce the prevalence of Salmonella in birds, better control of carcass washings and chiller tank management, and information placement on packages and campaigns to raise the awareness of the population about the need to control Salmonella contamination before consumption. On the other hand, it did not recommend better controls at scalding and defeathering. QMRA confirmed the beneficial effects of the recommended control measures. For example, as Salmonella prevalence in poultry increased from 4.04 per cent to 50 per cent, the risk of infection per serving also increased from 0.0080 to 0.071. Although better controls in washings and chiller tank management did not affect the risk of infection, it reduced Salmonella counts on carcasses. We assume that the presence of Salmonella on carcasses was due to improper thermal processing or cross-contamination, which increased the risk from 0.0080 to 0.015962. The RBA demonstrated the logic involved in the adoption of control measures, and this can be helpful in the risk management of food safety issues.

A multi-period multi-modal stochastic supply chain model under COVID pandemic: A poultry industry case study in Mississippi

The poultry industry is one of the most important agricultural sectors, which constitutes a significant part of the per capita consumption of protein and meat. Integrating operations of poultry industry sections including production, distribution and consumption becomes vital. Although the proper poultry supply chain has been established and made plenty of benefits for a long time, the global outbreak of COVID-19 shows that operations under pandemic are still challenge for the poultry industry. In this paper, the impacts of pandemic on poultry industry is investigated by developing a multi-period multi-modal stochastic poultry supply chain. Two models are developed aiming to mitigate the negative effects of pandemic occurrence through product stocking policy. In the first model, distribution system is in accordance with a multi-component structure, while the second model allows direct connections between suppliers (farmers) and demanders (customers). In both models, poultry productions are negatively affected by COVID 19. Due to the complexity of the model, a hybrid solution approach based on Branch and Cut and Dynamic Programming is developed. To validate the performance of the proposed model and solution procedure, a case study on the broiler industry in the state of Mississippi is performed. The results show that storing poultry products in the pre-pandemic along with direct logistics during pandemic period can save the broiler supply chain cost up to 30%.

Development of new strategy combining heat treatment and phage cocktail for post-contamination prevention

Heat treatment is an effective method for ensuring food safety and quality by controlling microbial contamination. However, food poisoning outbreaks have continuously occurred in heat-treated products due to improper thermal treatment and/or post-contamination of foodborne pathogens. This study proposes a novel strategy combining thermostable bacteriophages with thermal processing of food production plants to control foodborne pathogens and even bacterial contamination. Typically, bacteriophages' susceptibility to heat is a major challenge to their application with thermal processing, we isolated thermostable bacteriophages by a modified isolation method of applying heat to samples and characterized the thermostable bacteriophages. Furthermore, we optimized the bacteriophage cocktail components to expand the controllable host range and reduce the risk of bacteriophage resistance development. Finally, we verified this antibacterial strategy by combining heat treatment with thermostable bacteriophages in model systems, including milk and chicken breast. After the phage cocktail and heat treatment, we artificially contaminated the food products to mimic the post-contamination event. Surprisingly, the remaining bacteriophages that withstood heat treatment significantly reduced the number of post-contaminated Salmonella. Altogether, thermostable phages could be applied as complementary tools to control post-contamination after thermal processing of food products.

Predictive Modeling for the Growth of Salmonella spp. in Liquid Egg White and Application of Scenario-Based Risk Estimation

The objective of the study was to develop a predictive model of Salmonella spp. growth in pasteurized liquid egg white (LEW) and to estimate the salmonellosis risk using the baseline model and scenario analysis. Samples were inoculated with six strains of Salmonella, and bacterial growth was observed during storage at 10–37 °C. The primary models were developed using the Baranyi model for LEW. For the secondary models, the obtained specific growth rate (μ_max) and lag phase duration were fitted to a square root model and Davey model, respectively, as functions of temperature (R² ≥ 0.98). For μ_max, the values were satisfied within an acceptable range (A_f, B_f: 0.70–1.15). The probability of infection (P_inf) due to the consumption of LEW was zero in the baseline model. However, scenario analysis suggested possible salmonellosis for the consumption of LEW. Because Salmonella spp. proliferated much faster in LEW than in egg white (EW) during storage at 20 and 30 °C (p < 0.01), greater P_inf may be obtained for LEW when these products are stored at the same conditions. The developed predictive model can be applied to the risk management of Salmonella spp. along the food chain, including during product storage and distribution.

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

Food of animal origin, especially meat products, represent the main vehicle of foodborne pathogens and so are implicated in foodborne outbreaks. Poultry meat is a widely consumed food in various forms, but it is also a reservoir of thermotolerant Campylobacter and Salmonella bacterial species. To assess human health risks associated with pathogenic bacteria in poultry meat, the use of quantitative microbial risk assessment (QMRA) has increased over the years as it is recognized to address complex food safety issues and is recommended by health authorities. The present project reviewed poultry meat QMRA, identified key steps of the farm-to-fork chain with significant impacts on food safety, highlighted current knowledge gaps, and provided risk mitigation advices. A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)-based systematic analysis was carried out and enabled the collection of 4056 studies including 42 QMRA kept for analysis after screening. The latter emphasized Campylobacter spp. and Salmonella spp. contaminations during the consumer stage as the main concern. The role of consumer handling on cross-contamination and undercooking events were of major concern. Thus, proper hygiene and safety practices by consumers have been suggested as the main intervention and would need to be followed with regular surveys to assess behavior changes and reduce knowledge gaps.

Distribution of Salmonella Serovars in Humans, Foods, Farm Animals and Environment, Companion and Wildlife Animals in Singapore

We analyzed the epidemiological distribution of Salmonella serovars in humans, foods, animals and the environment as a One-Health step towards identifying risk factors for human salmonellosis. Throughout the 2012-2016 period, Salmonella ser. Enteritidis was consistently the predominating serovar attributing to >20.0% of isolates in humans. Other most common serovars in humans include Salmonella ser. Stanley, Salmonella ser. Weltevreden, Salmonella ser. Typhimurium and Salmonella ser. 4,5,12:b:-(dT+). S. Enteritidis was also the most frequent serovar found among the isolates from chicken/chicken products (28.5%) and eggs/egg products (61.5%) during the same period. In contrast, S. Typhimurium (35.2%) and Salmonella ser. Derby (18.8%) were prevalent in pork/pork products. S. Weltevreden was more frequent in seafood (19.2%) than others (≤3.0%). Most isolates (>80.0%) from farms, companion and wildlife animals belonged to serovars other than S. Enteritidis or S. Typhimurium. Findings demonstrate the significance of a One-Health investigative approach to understand the epidemiology Salmonella for more effective and integrated surveillance systems.

Modeling the Reduction and Cross-Contamination of Salmonella in Poultry Chilling Process in China

: The study was to establish a predictive model for reduction and cross-contamination of Salmonella on chicken in chilling process. Reduction of Salmonella on chicken was 0.75 ± 0.04, 0.74 ± 0.08, and 0.79 ± 0.07 log CFU/g with 20, 50, and 100 mg/L of chlorine, respectively. No significant differences of bacterial reductions with 20-100 mg/L of chlorine were found and a Normal (-0.75, 0.1) distribution could describe the uncertainty of bacterial reductions. Inoculated and non-inoculated chicken samples were washed together and bacterial transfer rates among them were 0.13%-0.004% with 20-100 mg/L of chlorine. No significant differences of transfer rates with 50-100 mg/L of chlorine were observed and a Triangle (-2.5, -1.5, -1.1) distribution could describe the log transfer rate. Additionally, a 3-factor response surface model based on the central composite design was developed to evaluate the effects of initial contamination level (1-5 log CFU/g), pre-chill incidence (3%-40%) and chlorine concentration (0-100 mg/L) on post-chill incidence. The post-chill incidences in these treatments were within 30%-91.7%. The developed model showed a satisfactory performance to predict the post-chill incidence as evidenced by statistical indices (pseudo-R2 = 0.9; p < 0.0001; RMSE = 0.21) and external validation parameters (Bf = 1.02; Af = 1.11).