Risk Of Salmonellosis Research Articles

Development and Validation of a Predictive Model for Growth of Salmonella Infantis in Ground Turkey

Most retail samples (25 g) of ground turkey contain no or low levels of Salmonella. However, temperature abuse after retail can lead to spread and growth of Salmonella in the package. In addition, it can lead to levels that pose a significant risk of salmonellosis. This is especially true when the serotype is a top human clinical isolate, like Infantis. Therefore, the current study was undertaken to develop and validate a predictive model for growth of Salmonella Infantis in ground turkey subjected to temperature abuse. The purpose was to fill a gap for serotype-specific data and models in risk assessments for this pathogen and food combination. Storage trials with a low initial inoculum (0.85 log10) of Salmonella Infantis in commercial ground turkey samples (0.2 g) with native microflora were conducted at 16 to 40°C for 0 to 28 h. Salmonella was enumerated in ground turkey samples using an automated, whole sample enrichment, miniature, most probable number (MPN) assay. The MPN data were fitted to a three-phase linear primary model. Secondary models for primary model parameters were developed and used in the primary model to create a tertiary model that predicted growth of Salmonella Infantis in ground turkey as a function of time and temperature. Data and tertiary model predictions were evaluated using the test data, model performance, and model validation criteria of the Acceptable Prediction Zones method in the Validation Software Tool. The tertiary model predictions were considered to have acceptable bias and accuracy when the proportion of residuals (observed – predicted) in the partly and fully acceptable prediction zones (pAPZ) was ≥ 0.7. The overall pAPZ of the tertiary model was 0.866 for dependent data (n = 406) and 0.853 for independent data for interpolation (n = 177). However, there were local prediction problems that limited the validated prediction range to a region from 0 to 8 h at 16 to 40°C. Nonetheless, this validation range was sufficient to simulate temperature abuse of ground turkey during meal preparation in the consumers’ home. Thus, the model fills an important data and modeling gap in risk assessments for Salmonella and ground turkey. Additional data is needed to repair and fully validate the model.

Salmonella Prevalence in Raw Cocoa Beans and a Microbiological Risk Assessment to Evaluate the Impact of Cocoa Liquor Processing on the Reduction of Salmonella

Salmonella in raw cocoa beans (n = 870) from main sourcing areas over nine months was analyzed. It was detected in 71 (ca. 8.2%) samples, with a contamination level of 0.3–46 MPN/g except for one sample (4.1 × 104 CFU/g). Using prevalence and concentration data as input, the impact of thermal treatment in cocoa processing on the risk estimate of acquiring salmonellosis by a random Belgian chocolate consumer was calculated by a quantitative microbiological risk assessment (QMRA) approach. A modular process risk model from raw cocoa beans to cocoa liquor up to a hypothetical final product (70–90% dark chocolate tablet) was set up to understand changes in Salmonella concentrations following the production process. Different thermal treatments during bean or nib steam, nib roasting, or liquor sterilization (achieving a 0–6 log reduction of Salmonella) were simulated. Based on the generic FAO/WHO Salmonella dose–response model and the chocolate consumption data in Belgium, salmonellosis risk per serving and cases per year at population level were estimated. When a 5 log reduction of Salmonella was achieved, the estimated mean risk per serving was 3.35 × 10−8 (95% CI: 3.27 × 10−10–1.59 × 10−7), and estimated salmonellosis cases per year (11.7 million population) was 88 (95% CI: <1–418). The estimated mean risk per serving was 3.35 × 10−9 (95% CI: 3.27 × 10−11–1.59 × 10−8), and the estimated salmonellosis cases per year was 9 (95% CI: <1–42), for a 6 log reduction. The current QMRA model solely considered Salmonella reduction in a single-step thermal treatment in the cocoa process. Inactivation obtained during other process steps (e.g. grinding) might occur but was not considered. As the purpose was to use QMRA as a tool to evaluate the log reduction in the cocoa processing, no postcontamination from the processing environment and ingredients was included. A minimum of 5 log reduction of Salmonella in the single-step thermal treatment of cocoa process was considered to be adequate.

Risk Assessment Predicts Most of the Salmonellosis Risk in Raw Chicken Parts is Concentrated in Those Few Products with High Levels of High-Virulence Serotypes of Salmonella

Salmonella prevalence declined in U.S. raw poultry products since adopting prevalence-based Salmonella performance standards, but human illnesses did not reduce proportionally. We used Quantitative Microbial Risk Assessment (QMRA) to evaluate public health risks of raw chicken parts contaminated with different levels of all Salmonella and specific high- and low-virulence serotypes. Lognormal Salmonella level distributions were fitted to 2012 USDA-FSIS Baseline parts survey and 2023 USDA-FSIS HACCP verification sampling data. Three different Dose-Response (DR) approaches included (i) a single DR for all serotypes, (ii) DR that reduces Salmonella Kentucky ST152 virulence, and (iii) multiple serotype-specific DR models. All scenarios found risk concentrated in the few products with high Salmonella levels. Using a single DR model with Baseline data (μ = −3.19, σ = 1.29 Log CFU/g), 68% and 37% of illnesses were attributed to the 0.7% and 0.06% of products with >1 and >10 CFU/g Salmonella, respectively. Using distributions from 2023 HACCP data (μ = −5.53, σ = 2.45), 99.8% and 99.0% of illnesses were attributed to the 1.3% and 0.4% of products with >1 and >10 CFU/g Salmonella, respectively. Scenarios with serotype-specific DR models showed more concentrated risk at higher levels. Baseline data showed 92% and 67% and HACCP data showed >99.99% and 99.96% of illnesses attributed to products with >1 and >10 CFU/g Salmonella, respectively. Regarding serotypes using Baseline or HACCP input data, 0.002% and 0.1% of illnesses were attributed to the 0.2% and 0.4% of products with >1 CFU/g of Kentucky ST152, respectively, while 69% and 83% of illnesses were attributed to the 0.3% and 0.6% of products with >1 CFU/g of Enteritidis, Infantis, or Typhimurium, respectively. Therefore, public health risk in chicken parts is concentrated in finished products with high levels and specifically high levels of high-virulence serotypes. Low-virulence serotypes like Kentucky contribute few human cases.

Effect of a Bacillus subtilis plus Yeast Cell Wall Synbiotic on Salmonella Enteritidis Colonization in Ceca of Layer Pullets

Salmonella Enteritidis (SE) is a major contamination concern in eggs and risk for Salmonellosis in humans. Strains of Bacillus subtilis and yeast cell wall can be used as substitutes for antibiotic substances in feed against Salmonella in poultry. The objective of this study was to assess the effect of BacPack® (Quality Technology International, Inc., Elgin, IL, USA) Q1+1 (BPQ11), a feed additive combination of a Bacillus subtilis strain and Saccharomyces cerevisiae cell wall, on SE cecal colonization in Lohmann LSL pullets. A control group (CON) and a test group (BPQ) were each randomly assigned 100-day-old chicks. CON was fed a corn–soybean meal-based vegetarian mash diet, and BPQ was fed the control diet supplemented with BPQ11 for the duration of the study. At 8 days of age, chicks were orally challenged with a nalidixic acid-resistant SE strain at a dose of 6.3 × 107 colony forming units (CFUs) per bird. At 7, 11, 15, and 19 days post-challenge (DPC), 25 birds per group were euthanized, and their cecal contents were collected and analyzed for SE. SE counts were 6.88, 7.98, 7.79, and 7.50 in CON and 7.18, 7.31, 6.35, and 6.30 log10 CFU/g in BPQ at 7, 11, 15, and 19 DPC, respectively. SE did not differ between CON and BPQ at 7 DPC; however, BPQ had lower (p &lt; 0.0001) SE at 11 (−0.67), 15 (−1.45), and 19 (−1.20 log10 CFU/g) DPC. Results indicate that synbiotic BPQ11 may be a useful dietary pre-harvest tool for SE management in layer birds.

Identifying a list of Salmonella serotypes of concern to target for reducing risk of salmonellosis.

There is an increasing awareness in the field of Salmonella epidemiology that focusing control efforts on those serotypes which cause severe human health outcomes, as opposed to broadly targeting all Salmonella, will likely lead to the greatest advances in decreasing the incidence of salmonellosis. Yet, little guidance exists to support validated, scientific selection of target serotypes. The goal of this perspective is to develop an approach to identifying serotypes of greater concern and present a case study using meat- and poultry-attributed outbreaks to examine challenges in developing a standardized framework for defining target serotypes.

Risks of Salmonellosis Linked to the Consumption of Lettuce Grown on the Outskirts and in Unexploited Intra-Urban Areas of the City of Bouaké, Central-Côte d’Ivoire

Lettuce is one of the most popular and consumed vegetables in the world. It could be contaminated with Salmonella spp. which would lead to food poisoning. The objective of this study was to quantitatively assess the risk of salmonellosis linked to the consumption of lettuce produced in Bouaké (Central-Côte d’Ivoire). A survey of 138 urban lettuce producers and 384 salad lettuce consumers was first conducted. Then, microbiological analyzes were carried out on forty-five lettuce samples collected in the city of Bouaké. A probabilistic approach was followed to quantitatively assess the risks associated with the consumption of lettuce. Finally, the risk of ingestion of the infectious dose which is 105 cells of Salmonella spp. was estimated by a Monte Carlo type simulation. Microbiological analyzes showed that Salmonella spp. loads ranged from 0 ± 0 CFU/g to 7.73.102 ± 2.33.101 CFU/g. Furthermore, the prevalence of Salmonella spp. in lettuce was 77.78%. The risk of salmonellosis exists and is 6.36% to 6.56%; i.e. 6,360 to 6,560 cases per 100,000 inhabitants. This study showed that lettuces were contaminated with Salmonella spp. There is a risk of developing typhoid or paratyphoid salmonellosis following their consumption.

Prevalence and antibiotic resistance of Salmonella in organic and non-organic chickens on the Eastern Shore of Maryland, USA.

Salmonella infections have been intensely increasing and becoming a universal public health crisis. This study investigated the prevalence of Salmonella in organic and non-organic chickens and the antimicrobial resistance profiles and virulence genes (invA, pagC, and spvC) in recovered Salmonella isolates. Whole chicken carcasses [organic (n = 240) and non-organic (n = 240)] were obtained monthly for 1 year (n = 480) from a retail store on the Eastern Shore of Maryland. Salmonella isolation and identification were conducted by following the whole carcass enrichment method recommended by USDA-FSIS. Confirmed Salmonella isolates (organic n = 76; non-organic n = 137) were serotyped and tested for antibiotic susceptibility and virulence genes using standard methods. Forty-nine percent (237/480) of the carcasses were positive for Salmonella. Organic and non-organic positivity rates were 37.1 and 61.8%, respectively. A significantly higher Salmonella contamination was observed in non-organic chickens (p < 0.05). The most common serovars were Salmonella Kentucky (47%), S. Infantis (35%), S. Enteritidis (6%), S. Typhimurium (5%), and S. Blockley (4%). Isolates were frequently resistant to at least one antibiotic (91.24%) or multidrug resistant (45.54%). Resistance was observed to tetracycline (82.8%), minocycline (42.3%), nitrofurantoin (40.3%), cefazolin (38.3%), ampicillin (32.1%), and ceftriaxone (26%). All isolates were susceptible to fluoroquinolone, carbapenem, and glycylcycline. The majority of isolates (99.1%) possessed at least one of three virulence genes of concern and 4.2% tested positive for all three. Ninety-five, 89, and 6.6% of isolates contained invA, pagC, and spvC genes, respectively. The spvC gene was not detected in serovars recovered from organic chickens though 92% and 82% of isolates were positive for invA and pagC. The frequency of Salmonella recovered from non-organic chickens possessing invA, pagC, and spvC genes were 97.1, 89.8, and 10.2%, respectively. Detection of invA and pagC genes showed no significant difference (p > 0.05) between organic and non-organic chickens but a significantly higher spvC gene (p < 0.05) was detected in non-organic chickens due to the majority of S. Enteritidis (92.3%) exclusively recovered from non-organic chicken carried spvC gene. This study reveals a high prevalence of Salmonella in both organic and non-organic chickens, which exhibit resistance to vital antibiotics and carry virulence genes, thereby creating a potential risk of salmonellosis.

Quantitative microbiological risk assessments for Salmonella spp. contaminated Taiwanese salty chicken in the Taiwanese population

The aim of the study is to develop Salmonella spp. Quantitative microbial risk assessments (QMRA) and to evaluate the risk of Salmonellosis illness in the Taiwanese population after consumption of Taiwanese salty chicken (TSC). We assume that Salmonella spp. May contaminate the fresh raw chicken used in TSC. After transport to the diner, fresh raw chicken is received, cleaned, and surface-washed by diner staff. The TSC is then cooked and sold to consumers. We set four different cross-contamination scenarios to evaluate the contamination level of Salmonella spp. In TSC. We used a Monte Carlo simulation method, a probabilistic analysis method, and exceedance risk to evaluate the risk of Salmonellosis illness. When the exceedance risk was 5 %, and taking the Taiwanese population above 19 years old as an example, the rate of contracting Salmonellosis from the consumption of TSC will be 2.94 % (2.94 million per 100 million people) if the chef does not clean their hands, knives, or cutting boards. However, if the chef washes their hands, knives, and cutting boards with cold water and soap, the illness rate of Salmonellosis from consuming TSC will be 1.93E-04 % (193 per 100 million people). Sensitivity analysis indicates that the most important risk factor in the QMRAs of TSC is the temperature of the fresh raw chicken during transportation, following which were the Salmonella spp. Residual. If the staff of the diner separates the cooking tools used for raw ingredients and those for cooked food, the illness risk of Salmonellosis will be very low.

Prevalence and genomic characterization of Salmonella isolates from commercial chicken eggs retailed in traditional markets in Ghana.

Salmonella enterica are important foodborne bacterial pathogens globally associated with poultry. Exposure to Salmonella-contaminated eggs and egg-related products is a major risk for human salmonellosis. Presently, there is a huge data gap regarding the prevalence and circulating serovars of Salmonella in chicken eggs sold in Ghana. In this study, 2,304 eggs (pools of six per sample unit) collected from informal markets in Accra, Kumasi and Tamale, representing the three ecological belts across Ghana, were tested for Salmonella. Antimicrobial susceptibility testing and Whole Genome Sequencing (WGS) of the isolates were performed using standard microdilution protocols and the Illumina NextSeq platform, respectively. The total prevalence of Salmonella was 5.5% with a higher rate of contamination in eggshell (4.9%) over egg content (1.8%). The serovars identified were S. Ajiobo (n = 1), S. Chester (n = 6), S. Hader (n = 7), S. enteritidis (n = 2); and S. I 4:b:- (n = 8). WGS analysis revealed varied sequence types (STs) that were serovar specific. The S. I 4:b:- isolates had a novel ST (ST8938), suggesting a local origin. The two S. enteritidis isolates belonged to ST11 and were identified with an invasive lineage of a global epidemic clade. All isolates were susceptible to ampicillin, azithromycin, cefotaxime, ceftazidime, gentamicin, meropenem, and tigecycline. The phenotypic resistance profiles to seven antimicrobials: chloramphenicol (13%), ciprofloxacin (94%), and nalidixic acid (94%), colistin (13%), trimethoprim (50%) sulfamethoxazole (50%) and tetracycline (50%) corresponded with the presence of antimicrobial resistance (AMR) determinants including quinolones (gyrA (D87N), qnrB81), aminoglycosides (aadA1), (aph(3")-Ib aph(6)-Id), tetracyclines (tet(A)), phenicols (catA1), trimethoprim (dfrA14 and dfrA1). The S. enteritidis and S. Chester isolates were multidrug resistant (MDR). Several virulence factors were identified, notably cytolethal distending toxin (cdtB gene), rck, pef and spv that may promote host invasion and disease progression in humans. The findings from this study indicate the presence of multidrug resistant and virulent strains of Salmonella serovars in Ghanaian chicken eggs, with the potential to cause human infections. This is a critical baseline information that could be used for Salmonella risk assessment in the egg food chain to mitigate potential future outbreaks.

Combined effects of UVC waterproof LED and slightly acidic electrolyzed water (SAEW) on the reduction of bacterial pathogens risk in fresh cabbage and mung bean sprouts

This study investigated the combined effects of washing with slightly acidic electrolyzed water (SAEW; 30 ppm) and ultraviolet-C waterproof light emitting diodes (UVC W-LED; 275 nm) on Salmonella spp. and Listeria monocytogenes numbers in fresh-cut shredded cabbage and mung bean sprouts. The risk reduction effect of washing was also evaluated by quantitative microbial risk assessment (QMRA) using @Risk. The combined treatment when used for 5 min, effectively decreased the contamination levels of hygiene indicator microorganisms, Salmonella spp., and L. monocytogenes in shredded cabbage (1.13–1.44 log CFU/g) and mung bean sprouts (1.45–1.64 log CFU/g). Neither pathogen survived in SAEW + UVC W-LED. The contamination levels of both pathogens increased from market to home, but L. monocytogenes grew more slowly than Salmonella spp. in cabbage and mung bean sprouts. Washing lowered the average probability risk of both pathogens in cabbage (Salmonella; 1.05 × 10−1, Listeria; 3.16 x 10−5) and mung bean sprouts (Salmonella; 6.62 × 10−2, Listeria; 1.25 × 10−7). The probability risk of salmonellosis and listeriosis was higher in cabbage than in mung bean sprouts, and the probability of listeriosis risk increased 10 times for the susceptible population. Transportation time from market to home is the most influential factor in increasing the risk of both pathogens in cabbage and mung bean sprouts. The synergistic effect of UVC W-LED with SAEW for washing fresh vegetables can be expected to decrease contamination levels and prevent cross-contamination during washing processing.

Multistate outbreak of turtle-associated salmonellosis highlights ongoing challenges with the illegal sale and distribution of small turtles.

The sale and distribution of small turtles (shell length <4 inches) as pets has been banned in the United States since 1975 because of the risk of Salmonella transmission, especially to children. Despite this 48-year-old ban, salmonellosis outbreaks continue to be linked to contact with small turtles. During investigations of turtle-associated outbreaks, information regarding the turtle farm of origin is difficult to obtain because turtles are commonly sold by transient vendors. During 2020-2021, public health officials investigated a multistate illness outbreak caused by Salmonella enterica serotype Typhimurium linked to pet small turtles. Cases were defined as a laboratory-confirmed Salmonella Typhimurium infection highly related (within 0-6 allele differences) to the outbreak strain based on whole-genome sequencing analysis by core-genome multilocus sequence typing with illness onset occurring during 27 August 2020-14 May 2021. Forty-three patients were identified from 12 states; of these, 35% (15/43) were children <5 years old. Among patients with available information, 37% (14/38) were hospitalized, and one death was reported. Seventy-four percent (25/34) of patients reported turtle exposure in the week before illness onset, and 84% (16/19) specified exposure to small turtles. The outbreak strain was isolated from samples collected from a Pennsylvania patient's small turtle tank. Two patients reported purchasing their small turtles from pet stores. Salmonella Braenderup was isolated from samples collected from small turtles and their habitat at one of these stores; however, at that time, this strain was not associated with any human illnesses. This investigation was notable because of the documented sale of small turtles from several pet stores combined with the identification of a single small turtle supplier to these pet stores. The high proportion of children involved in this outbreak highlights the continued need to educate the pet industry as well as parents and caregivers about the risk of turtle-associated salmonellosis especially in children. Understanding and addressing the persisting challenges related to the illegal sale and distribution of small turtles could reduce the burden of turtle-associated salmonellosis.

Dominant Salmonella Serovars in Australian Broiler Breeder Flocks and Hatcheries: a Longitudinal Study.

A longitudinal study was conducted to determine the dominance and prevalence of Salmonella enterica subsp in Australian broiler breeder flocks and hatcheries. Twenty-two flocks (n = 3339 samples) were sampled over 6 time points beginning at placement until week 40. Hatcheries (n = 274 samples) were sampled following removal of chicks hatched from eggs originating from the 22 donor parent flocks. The percent of positive flocks (36%) and frequency of positive samples (15.6%) were highest during rearing at week 7. The frequency of positive samples decreased over the 40 weeks; however, the number of positive flocks remained relatively consistent. Geographical location had a greater influence on Salmonella detection frequency than company sample origin, despite differing management and vaccination protocols within and between companies. Twelve serovars were detected in total. The predominant serovars during rearing were Salmonella Mbandaka (32%), S. Saintpaul (27%), and S. Liverpool (18%). The predominant serovars detected during production were S. Cubana (27%), S. Saintpaul (24%), and S. Havana (13%). Salmonella Typhimurium, S. Ohio, and S. Hessarek were detected in the hatcheries. Of the serovars detected, only S. Typhimurium and S. Ohio were found in both broiler breeder flocks and hatcheries. However, detection did not correspond to the status of the flock eggs feeding into the hatchery. This study provides an up-to-date capture of the current Salmonella serovars circulating in the broiler breeder industry. Continued surveillance within the Australian Chicken Meat industry is imperative to mitigate and reduce the risk of salmonellosis in the community related to chicken meat. IMPORTANCE This study identified prevalent and dominant Salmonella enterica subsp in Australian Broiler Breeder flocks, as well as in hatcheries post chick hatch and removal, from eggs originating from these donor parent flocks. The captured Salmonella data was further compared to the most common Salmonella serovars isolated from broilers, as well as human salmonellosis notification data, which is useful for consideration of the circulating serovars within the chicken meat industry and their significance in public health. As there are multiple entry points for Salmonella during the entire chicken meat production chain that can lead to carcass contamination, it is important to distinguish serovars present between the different stages of vertical integration to implement and enable Salmonella control strategies.

Is There a Shift in Salmonella Diversity Among Poultry in Northern India?

The present study was conducted to determine the serotype diversity of Salmonella among poultry in northern India. A total of 101 poultry droppings from 30 farms in the Jammu and Kashmir union territory were analyzed. Nineteen isolates of Salmonella were obtained, and these belonged to four serotypes: Salmonella enterica enterica serotype Kentucky (n = 3), Salmonella enterica enterica serotype Infantis (n = 5), Salmonella enterica enterica serotype Agona (n = 4), and Salmonella enterica enterica serotype Typhimurium (n= 7). The study has isolated some Salmonella serotypes that are infrequently reported in India. Some of the isolated serotypes are reported to be endemic for human nontyphoidal salmonellosis cases in the region. Whether this indicates a shift in the serotype pattern in poultry in the region needs to be investigated further. Nevertheless, the study clearly indicates the risk of foodborne salmonellosis associated with consumption of contaminated poultry and poultry products in the region.

Poultry Food Assess Risk Model for Salmonella and Chicken Gizzards: I. Initial Contamination

The Poultry Food Assess Risk Model (PFARM) project was initiated in 1995 to develop data collection and modeling methods for simulating the risk of salmonellosis from poultry food produced by individual production chains. In the present study, the Initial Contamination (IC) step of PFARM for Salmonella and chicken gizzards (CG) was conducted as a case study. Salmonella prevalence (Pr), number (N), and serotype/zoonotic potential (ZP) data (n = 100) for one sample size (56 g) of CG were collected at meal preparation (MP), and then Monte Carlo simulation (MCS) was used to obtain data for other sample sizes (112, 168, 224, 280 g). The PFARM was developed in Excel and was simulated with @Risk. Data were simulated using a moving window of 60 samples to determine how Salmonella Pr, N, and ZP changed over time in the production chain. The ability of Salmonella to survive, grow, and spread in the production chain and food, and then cause disease in humans was ZP, which was based on U. S. Centers for Disease Control and Prevention data for salmonellosis. Of 100 CG samples tested, 35 were contaminated with Salmonella with N from 0 to 0.809 (median) to 2.788 log per 56 g. Salmonella serotype Pr per 56 g was 16% for Kentucky (ZPmode = 1.1), 9% for Infantis (ZPmode = 4.4), 6% for Enteritidis (ZPmode = 5.0), 3% for Typhimurium (ZPmode = 4.9), and 1% for Thompson (ZPmode = 3.7). Results from MCS indicated that Salmonella Pr, N, and ZP among portions of CG at MP changed (P ≤ 0.05) over time in the production chain. Notably, the main serotype changed from Kentucky (low ZP) to Infantis (high ZP). However, the pattern of change for Salmonella Pr, N, and ZP differed over time in the production chain and by the statistic used to characterize it. Thus, a performance standard (PS) based on Salmonella Pr, N, or ZP at testing or MP will likely not be a good indicator of poultry food safety or risk of salmonellosis.

Quantitative risk assessment of salmonellosis in Cambodian consumers through chicken and pork salad consumption

Salmonella is a globally important foodborne bacterial pathogen that poses a high risk to human health. This study aimed to estimate the risk to Cambodian consumers from acquiring salmonellosis after consuming chicken and pork salad, using a quantitative microbial risk assessment (QMRA). Chicken and pork salads are typical Cambodian dishes containing raw vegetables and boiled chicken meat or pork. As previously described, chicken meat and pork samples (n = 204 of each) were collected from traditional markets in 25 Cambodian provinces to generate data on Salmonella contamination. Salad preparation and consumption practices were surveyed in 93 Cambodian households and this information was used to design an experiment to assess Salmonella cross-contamination from raw meat to ready-to-eat salad. In the part of the study reported here, data on consumption, Salmonella in salad, dose-response, and predicted salmonellosis were modeled using Monte Carlo simulations at 10,000 iterations. The prevalence of Salmonella in chicken meat and pork were set to 42.6 and 45.1%, respectively, with average most probable number (MPN) per gram of Salmonella in chicken meat was 10.6 and in pork 11.1 MPN/g, based on an earlier study. Half of the interviewed households cooked meat for the salad directly after purchase. The QMRA model showed that the modeled annual risk of salmonellosis from consuming chicken salad, pork salad and both chicken and pork salad were 11.1% probability of illness per person per year (90% CI 0.0–35.1), 4.0% (90% CI 0.0–21.3), and 14.5% (90% CI 0.0–33.5), respectively. The factors most influencing the estimate were cross-contamination while preparing the salad, followed by the prevalence of Salmonella in chicken meat and pork at the market. The wide confidence interval for the incidence was mainly due to the variability in reducing bacteria concentration by cooking and salad consumption. The predicted risk of salmonellosis due to chicken and pork salad consumption is high, and the study provides evidence supporting control measures of improving the safety of retailed chicken and pork obtained from markets to households and improving food preparation methods in the household.

Quantitative Risk Assessment for Salmonella in Lettuce (Lactuca sativa) Consumed in Benin, West Africa

The present study aims at quantitatively assessing the risk associated with Salmonella in lettuce (Lactuca sativa) consumed in Benin (West Africa). To that end, a survey was conducted involving 550 respondents to determine the conditions under which the product is handled along the supply chain and its consumption pattern. The prevalence and concentration of Salmonella in lettuce were collected from the literature. The consumption data and the data on Salmonella concentrations in lettuce were combined to estimate the exposure to Salmonella using a probabilistic risk assessment method. The @Risk software package (Palisade USA) was used to run Monte Carlo simulations with 10,000 iterations. Three dose-response models were used to assess the risk of salmonellosis. Different scenarios were tested to identify factors that could influence the risk of salmonellosis. The results showed that lettuce is exposed to temperature abuse under inappropriate hygienic conditions. In 90% of the cases, the exposure to Salmonella was between 3 and 7 log CFU/serving. The risk of salmonellosis per serving varied from 7.7% to 95% depending on the dose-response used with the scenario taking into account the current handling conditions of the lettuce. In contrast, when considering the scenario where the cold chain is respected along the supply chain, the risk of salmonellosis varied from 0% to 3.3% depending on the dose response used. The study highlights the importance of the cold chain, good agricultural practices and good hygienic practices to reduce exposure to Salmonella through the consumption of lettuce and thus the risk of salmonellosis.

Codex Alimentarius Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance Are Incompatible with Available Surveillance Data

Foodborne antimicrobial-resistant (AMR) microorganisms are a global food safety concern. Antimicrobial drug use (AMU) in livestock may increase the risk of resistant foodborne bacterial infections in humans via contaminated animal products. Consequently, countries have implemented different livestock AMU restriction policies, opening the potential for trade disputes. AMR risk equivalence between countries with different AMU policies must be established by using scientifically justified risk assessments. The Codex Alimentarius Commission's Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance (AMR Codex) recommends an approach that requires quantification of detailed information, for which, in many instances, little to no data exist. Using AMR Salmonella exposure from beef consumption as an example, we demonstrate the difficulty of implementing the AMR Codex by comparing key regionally specific parameters within the United States and European Union, two regions with substantial beef production and consumption, robust foodborne pathogen sampling and surveillance systems, and different AMU policies. Currently, neither region fully captures data for key regional variables to populate a detailed risk assessment as outlined in the AMR Codex, nor are they able to adequately link AMU in livestock to AMR infections in humans. Therefore, the AMR Codex guidelines are currently aspirational and not a viable option to assess the impact of livestock AMU reductions on the human health risk of AMR salmonellosis from beef or produce regionally comparable estimates of risk. More flexible risk assessment guidelines that more directly link livestock AMU to human health risk and are amenable to currently available data are needed to allow for country variations and to calculate comparable regional risk estimates, which can be used to guide international trade policy.

Pet Reptiles in Poland as a Potential Source of Transmission of Salmonella.

Reptiles are considered a potential source of Salmonella transmission to humans. The aim of this research was to determine the incidence of Salmonella in pet reptiles in Poland and to examine Salmonella isolates with regard to their biochemical characteristics, serotype, antimicrobial susceptibility, and pathogenic and zoonotic potential. The research material consisted of 67 reptile faeces samples. The taxonomic affiliation of the Salmonella isolates was determined by MALDI-TOF mass spectrometry, biochemical analyses, and serotyping; whole genome sequencing (WGS) analysis was performed on three isolates whose serotype could not be determined by agglutination. The antimicrobial susceptibility of the Salmonella isolates was determined by the broth dilution method, and in the case of some antimicrobials by the disk diffusion method. The pathogenic and zoonotic potential of the identified serotypes was estimated based on available reports and case studies. The presence of Salmonella was confirmed in 71.6% of faecal samples, with the highest incidence (87.1%) recorded for snakes, followed by lizards (77.8%) and turtles (38.9%). All isolates (n = 51) belonged to the species S. enterica, predominantly to subspecies I (66.7%) and IIIb (25.5%). Among these, 25 serotypes were identified, including 10 that had previously been confirmed to cause reptile-associated salmonellosis (RAS). Salmonella isolates were susceptible to all antimicrobial substances used except streptomycin, to which 9.8% of the strains showed resistance. None of the strains contained corresponding resistance genes. The study demonstrates that pet reptiles kept in Poland are a significant reservoir of Salmonella and contribute to knowledge of the characteristics of reptilian Salmonella strains. Due to the risk of salmonellosis, contact with these animals requires special hygiene rules.

Growth of food-borne pathogens Listeria and Salmonella and spore-forming Paenibacillus and Bacillus in commercial plant-based milk alternatives

The objective of the present study was to compare the growth of food-pathogens Listeria monocytogenes, Salmonella enterica, food spoilage Bacillus subtilis, an industrial milk product isolate, and spore-forming Paenibacillus in commercially available ultrahigh temperature processed (UHT) bovine milk and non-dairy, plant-based beverages (coconut, almond, cashew) stored at chilled and ambient temperatures (4 °C, 8 °C or 20 °C). Beverage samples were inoculated with a strain cocktail or individual strains of either Listeria or Salmonella, or Paenibacillus or Bacillus, respectively (approximately 1 × 103 CFU/mL). The findings indicate that the bacterial strains used in the study were capable of proliferating in plant-based beverages at higher rates than in bovine milk at 8 °C and 20 °C for Listeria and 20 °C for Salmonella and Paenibacillus, respectively. Bacillus subtilis grew equally fast in bovine milk and plant-based almond drink at 20 °C. No statistically significant difference (p > 0.05) in growth rates between different types of tested beverages was observed at 4 °C and at 8 °C for Listeria and Salmonella cocktails, respectively. These data suggest that plant-based beverages may present a significant risk for listeriosis and salmonellosis and post-opening recommendations should be carefully considered.

Genome-based analysis of infrequent Salmonella serotypes through the Thai pork production chain.

Salmonella is a prevalent zoonotic foodborne pathogen. Swine and pork are implicated as important sources of salmonellosis in humans. In Chiang Mai and Lamphun Provinces in northern Thailand, there has been a high prevalence of Salmonella persistence for over a decade. Infection is usually with dominant S. enterica serotypes, including serotypes Rissen and 1,4,[5],12:i:-. However, other serotypes also contribute to disease but are less well characterized. The whole genome sequencing data of 43 S. enterica serotypes isolated from pork production chain through 2011–2014, were used to evaluate genetic diversity and ascertain the possible source of Salmonella contamination based on Core Genome Multilocus Sequence Typing (cgMLST) approach. The Salmonella serotypes recovered from farms and slaughterhouses were re-circulating by swine environmental contamination. Conversely, the Salmonella contamination in the retail market represents cross-contamination from multiple sources, including contaminated foodstuffs. Salmonella contamination in the pork production chain has the competency for host cell adhesion, host cell invasion, and intracellular survival, which is enough for the pathogenicity of salmonellosis. In addition, all of these isolates were multi-drug resistant Salmonella, which contained at least 10 antimicrobial resistance genes. This result indicated that these S. enterica serotypes also pose a significant public health risk. Our findings support the need for appropriate surveillance of food-animal products going to market to reduce public exposure to highly pathogenic, multi-drug resistant Salmonella. Acquiring information would motivate all stakeholders to reinforce sanitation standards throughout the pork production chain in order to eradicate Salmonella contamination and reduce the risk of salmonellosis in humans.