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5 pages, 194 KiB

Open AccessEditorial

Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms

by Arícia Possas and Fernando Pérez-Rodríguez

Foods 2024, 13(10), 1551; https://doi.org/10.3390/foods13101551 - 16 May 2024

Cited by 1 | Viewed by 3430

Abstract

Despite significant efforts from government and industry, enteric foodborne diseases continue to pose a substantial public health challenge worldwide [...] Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

Research

Jump to: Editorial

13 pages, 1533 KiB

Open AccessArticle

Variability in Physicochemical Parameters and Its Impact on Microbiological Quality and Occurrence of Foodborne Pathogens in Artisanal Italian Organic Salami

by Frédérique Pasquali, Antonio Valero, Arícia Possas, Alex Lucchi, Cecilia Crippa, Lucia Gambi, Gerardo Manfreda and Alessandra De Cesare

Foods 2023, 12(22), 4086; https://doi.org/10.3390/foods12224086 - 10 Nov 2023

Cited by 1 | Viewed by 1500

Abstract

Artisanal salami is produced in small-scale production plants, where the lack of full automation might result in higher variability in food intrinsic properties. The aim of the present study was to evaluate the inter- and intra-batch variability in physicochemical parameters and its impact [...] Read more.

Artisanal salami is produced in small-scale production plants, where the lack of full automation might result in higher variability in food intrinsic properties. The aim of the present study was to evaluate the inter- and intra-batch variability in physicochemical parameters and its impact on microbial quality and occurrence of foodborne pathogens on 480 samples collected from six batches of an artisanal Italian production of organic salami. Relatively high total bacterial counts (TBC) were found on the surface of the table in the stuffing room (4.29 ± 0.40 log cfu/cm²). High loads of Enterobacteriaceae in the meat mixture of batch 2 and TBC in batch 5 were associated with a higher occurrence of bacterial pathogens. During ripening, water activity (a_w) and pH failed to reach values lower than 0.86 and 5.3, respectively. Six Staphylococcus aureus and four Listeria monocytogenes isolates were collected from the salami meat mixture during ripening and the processing environment. A total of 126 isolates of Enterobacteriaceae were characterized at a species level, with Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Citrobacter freundii isolated from the final products. Results suggest the relevance of first steps of production in terms of the hygiene of raw materials and handling during stuffing procedures, especially when the physicochemical parameters of the final products do not reach values that represent hurdles for foodborne pathogens. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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17 pages, 1412 KiB

Open AccessArticle

Use of Doehlert Matrix as a Tool for High-Throughput Screening of Organic Acids and Essential Oils on Miniaturized Pork Loins, Followed by Lab-Scale Validation That Confirmed Tested Compounds Do Not Show Synergistic Effects against Salmonella Typhimurium

by Cristina Resendiz-Moctezuma, Arianna P. L. Fonville, Bailey N. Harsh, Matthew J. Stasiewicz and Michael J. Miller

Foods 2023, 12(21), 4034; https://doi.org/10.3390/foods12214034 - 5 Nov 2023

Cited by 1 | Viewed by 1568

Abstract

The many possible treatments and continuously changing consumer trends present a challenge when selecting antimicrobial interventions during pork processing. Thirty-five potential antimicrobials were screened at commercial working concentrations by individually adding them to miniaturized (69 cm³) disks of pork loin ends, [...] Read more.

The many possible treatments and continuously changing consumer trends present a challenge when selecting antimicrobial interventions during pork processing. Thirty-five potential antimicrobials were screened at commercial working concentrations by individually adding them to miniaturized (69 cm³) disks of pork loin ends, followed by inoculation with Salmonella Typhimurium ATCC 19585. Two organic acids and nine essential oils significantly inhibited Salmonella counts on pork (p < 0.05). However, six compounds that represent different levels of significance (p < 0.05–p < 0.0001) were selected as independent variables to build a Response Surface Methodology model based on a Doehlert matrix (Doehlert Matrix—RSM): lactic acid 1.25%, formic acid 0.25%, cumin 0.25%, clove 0.25%, peppermint 0.5%, and spearmint 0.5%. The goal of the Doehlert Matrix—RSM was to study single and paired effects of these antimicrobials on the change in Salmonella over 24 h. The Doehlert Matrix—RSM model predicted that lactic acid, formic acid, cumin, peppermint, and spearmint significantly reduced Salmonella when added alone, while no significant interactions between these antimicrobials were found. A laboratory-scale validation was carried out on pork loin end slices, which confirmed the results predicted by the model. While this screening did not identify novel synergistic combinations, our approach to screening a variety of chemical compounds by implementing a miniaturized pork loin disk model allowed us to identify the most promising antimicrobial candidates to then formally design experiments to study potential interactions with other antimicrobials. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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11 pages, 1829 KiB

Open AccessArticle

Dynamic Thermal Treatments in Green Coconut Water Induce Dynamic Stress Adaptation of Listeria innocua That Increases Its Thermal Resistance

by Gerardo A. González-Tejedor, Alberto Garre, Asunción Iguaz, Ricardo Wong-Zhang, Pablo S. Fernández and Arícia Possas

Foods 2023, 12(21), 4015; https://doi.org/10.3390/foods12214015 - 3 Nov 2023

Cited by 1 | Viewed by 1644

Abstract

The global coconut water market is projected to grow in the upcoming years, attributed to its numerous health benefits. However, due to its susceptibility to microbial contamination and the limitations of non-thermal decontamination methods, thermal treatments remain the primary approach to ensure the [...] Read more.

The global coconut water market is projected to grow in the upcoming years, attributed to its numerous health benefits. However, due to its susceptibility to microbial contamination and the limitations of non-thermal decontamination methods, thermal treatments remain the primary approach to ensure the shelf-life stability and the microbiological safety of the product. In this study, the thermal inactivation of Listeria innocua, a Listeria monocytogenes surrogate, was evaluated in coconut water and in tryptone soy broth (TSB) under both isothermal (50–60 °C) and dynamic conditions (from 30 to 60 °C, with temperature increases of 0.5, 1 and 5 °C/min). Mathematical models were used to analyse the inactivation data. The Geeraerd model effectively described the thermal inactivation of L. innocua in both TSB and coconut water under isothermal conditions, with close agreement between experimental data and model fits. Parameter estimates and analysis revealed that acidified TSB is a suitable surrogate medium for studying the thermal inactivation of L. innocua in coconut water, despite minor differences observed in the shoulder length of inactivation curves, likely attributed to the media composition. The models fitted to the data obtained at isothermal conditions fail to predict L. innocua responses under dynamic conditions. This is attributed to the stress acclimation phenomenon that takes place under dynamic conditions, where bacterial cells adapt to initial sub-lethal treatment stages, leading to increased thermal resistance. Fitting the Bigelow model directly to dynamic data with fixed z-values reveals a three-fold increase in D-values with lower heating rates, supporting the role of stress acclimation. The findings of this study aid in designing pasteurization treatments targeting L. innocua in coconut water and enable the establishment of safe, mild heat treatments for refrigerated, high-quality coconut water. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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14 pages, 1684 KiB

Open AccessArticle

Unveiling Fresh-Cut Lettuce Processing in Argentine Industries: Evaluating Salmonella Levels Using Predictive Microbiology Models

by Sofia Griselda Cuggino, Arícia Possas, Guiomar Denisse Posada-Izquierdo, Martin Gustavo Theumer and Fernando Pérez-Rodríguez

Foods 2023, 12(21), 3999; https://doi.org/10.3390/foods12213999 - 1 Nov 2023

Cited by 1 | Viewed by 1893

Abstract

A survey was performed to gather information on the processing steps, conditions, and practices employed by industries processing ready-to-eat (RTE) leafy vegetables in Argentina. A total of seven industries participated in the survey. A cluster analysis of the data obtained was performed to [...] Read more.

A survey was performed to gather information on the processing steps, conditions, and practices employed by industries processing ready-to-eat (RTE) leafy vegetables in Argentina. A total of seven industries participated in the survey. A cluster analysis of the data obtained was performed to identify homogeneous groups among the participating industries. The data collected were used as inputs of two predictive microbiology models to estimate Salmonella concentrations after chlorine washing, during storage and distribution of final products, and to rank the different practices according to the final estimated Salmonella levels. Six different clusters were identified by evaluating the parameters, methods, and controls applied in each processing step, evidencing a great variability among industries. The disinfectant agent applied by all participating industries was sodium hypochlorite, though concentrations and application times differed among industries from 50 to 200 ppm for 30 to 110 s. Simulations using predictive models indicated that the reductions in Salmonella in RTE leafy vegetables would vary in the range of 1.70–2.95 log CFU/g during chlorine-washing depending on chlorine concentrations applied, washing times, and vegetable cutting size, which varied from 9 to 16 cm² among industries. Moreover, Salmonella would be able to grow in RTE leafy vegetables during storage and distribution, achieving levels of up to 2 log CFU/g, considering the storage and transportation temperatures and times reported by the industries, which vary from 4 to 14 °C and from 18 to 30 h. These results could be used to prioritize risk-based sampling programs by Food Official Control or determine more adequate process parameters to mitigate Salmonella in RTE leafy vegetables. Additionally, the information gathered in this study is useful for microbiological risk assessments. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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10 pages, 1267 KiB

Open AccessArticle

Mitigation of Salmonella in Ground Pork Products through Gland Removal in Pork Trimmings

by Reagan L. Jiménez, Mindy M. Brashears, Rossy Bueno López, David A. Vargas and Marcos X. Sanchez-Plata

Foods 2023, 12(20), 3802; https://doi.org/10.3390/foods12203802 - 17 Oct 2023

Cited by 2 | Viewed by 4170

Abstract

Bio-mapping studies conducted in pork harvest and fabrication facilities have indicated that Salmonella is prevalent and mitigations are needed to reduce the pathogen in trim and ground products. Salmonella can be isolated from the lymph nodes and can cause contamination in comminuted pork [...] Read more.

Bio-mapping studies conducted in pork harvest and fabrication facilities have indicated that Salmonella is prevalent and mitigations are needed to reduce the pathogen in trim and ground products. Salmonella can be isolated from the lymph nodes and can cause contamination in comminuted pork products. The objective of this study was to determine if physically removing topical and internal lymph nodes in pork products prior to grinding would result in the mitigation of Salmonella and a reduction in indicators in the final ground/comminuted products. In total, three treatment groups were assigned in a commercial pork processing facility as follows: (1) untreated control, (2) topical (surface) glands removed before grinding, and (3) topical, jowl, and internal lymph nodes and glands removed before grinding. Indicator microorganisms were determined using the BioMérieux TEMPO^® system and the quantification of Salmonella was performed using the BAX^® System Real-Time Salmonella SalQuant^® methodology. The removal of lymph nodes located on the topical and internal surfaces and in the jowl significantly (p < 0.05) reduced the presence of Salmonella and also reduced the presence of indicator organisms according to this study. Briefly, 2.5-Log CFU/sample of Salmonella was initially observed in the trim samples, and the ground samples contained 3.8-Log CFU/sample of Salmonella. The total numbers were reduced to less than 1-Log CFU/sample in both trim and ground products. This study indicates a need for lymph node mitigation strategies beginning prior to harvest, in order to prevent contamination in further-processed pork products. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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10 pages, 277 KiB

Open AccessCommunication

Prevalence of Foodborne Bacterial Pathogens and Antibiotic Resistance Genes in Sweets from Local Markets in Iran

by Babak Pakbin, Zahra Amani, Zahra Rahimi, Somayeh Najafi, Behnaz Familsatarian, Alireza Khakpoor, Wolfram Manuel Brück and Thomas B. Brück

Foods 2023, 12(19), 3645; https://doi.org/10.3390/foods12193645 - 2 Oct 2023

Cited by 3 | Viewed by 2269

Abstract

Background: This study aimed to investigate the prevalences of some important antibiotic-resistance genes (ARGs) and foodborne bacterial pathogens in sweet samples collected from local markets in Iran. Methods: Forty sweet samples were collected. Foodborne pathogens and ARGs were detected in the sweet samples [...] Read more.

Background: This study aimed to investigate the prevalences of some important antibiotic-resistance genes (ARGs) and foodborne bacterial pathogens in sweet samples collected from local markets in Iran. Methods: Forty sweet samples were collected. Foodborne pathogens and ARGs were detected in the sweet samples by conventional and multiplex PCR assays using species-specific primers. Results: Staphylococcus aureus, Cronobacter sakazakii, Shigella spp., Campylobacter jejuni, and Campylobacter coli were detected and identified in 47.5%, 20%, 45%, 5%, and 30% of the sweet samples, respectively. We found S. aureus and Shigella spp. were the most prevalent bacterial pathogens. S. aureus was found to be the most frequent pathogenic bacteria profiled in these samples. We also found a significant correlation between the presence of C. coli and Cr. sakazakii. We detected the bla_SHV resistance gene in 97.5% of the sweet samples; however, bla_TEM was detected in only one sample (2.5%). Conclusions: Regarding these results, we suggest preventive strategies such as implementing automation of food processing; monitoring the personal hygiene and health of food handlers, and testing regularly for antibiotic resistance in raw materials and products. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

15 pages, 2093 KiB

Open AccessEditor’s ChoiceArticle

Antilisterial and Antimicrobial Effect of Salvia officinalis Essential Oil in Beef Sous-Vide Meat during Storage

by Robert Gál, Natália Čmiková, Aneta Prokopová and Miroslava Kačániová

Foods 2023, 12(11), 2201; https://doi.org/10.3390/foods12112201 - 30 May 2023

Cited by 7 | Viewed by 2040

Abstract

If food is contaminated with pathogens such as Listeria monocytogenes, improper cooking during sous-vide preparation can lead to foodborne illnesses. In this study, it was found that L. monocytogenes were inactivated with both heat and the essential oil of Salvia officinalis (sage [...] Read more.

If food is contaminated with pathogens such as Listeria monocytogenes, improper cooking during sous-vide preparation can lead to foodborne illnesses. In this study, it was found that L. monocytogenes were inactivated with both heat and the essential oil of Salvia officinalis (sage EO) in beef tenderloin of the musculus psoas major that had undergone sous-vide processing. To determine whether the enhancement of the efficacy of heat treatment is prospective, L. monocytogenes and sage EO were mixed. Groups with L. monocytogenes alone and sage essential oil combined with L. monocytogenes and test groups without EO were established. The samples were vacuum-packed, inoculated with L. monocytogenes, and then cooked sous-vide for the predetermined duration at 50, 55, 60, or 65 °C. In both groups with sous-vide beef tenderloin, the total bacterial count, the coliforms bacterial count, and the amount of L. monocytogenes were assessed on days 0, 3, 6, 9, and 12. Over these days, the amounts of L. monocytogenes, coliform bacteria, and overall bacteria increased. The identification of bacterial strains in various days and categories was performed by MALDI-TOF mass spectrometry. The test group that was exposed to a temperature of 50 °C for 5 min had a higher overall bacterial count for each day that was assessed. Pseudomonas fragi and L. monocytogenes were the most isolated organisms from the test group and the treated group. To ensure the safety for the consumption of sous-vide beef tenderloin, it was found that the addition of natural antimicrobials could produce effective outcomes. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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21 pages, 1457 KiB

Open AccessArticle

Surface Hygiene Evaluation Method in Food Trucks as an Important Factor in the Assessment of Microbiological Risks in Mobile Gastronomy

by Michał Wiatrowski, Elżbieta Rosiak and Ewa Czarniecka-Skubina

Foods 2023, 12(4), 772; https://doi.org/10.3390/foods12040772 - 10 Feb 2023

Cited by 4 | Viewed by 4389

Abstract

Street food outlets are characterised by poor microbiological quality of the food and poor hygiene practices that pose a risk to consumer health. The aim of the study was to evaluate the hygiene of surfaces in food trucks (FT) using the reference method [...] Read more.

Street food outlets are characterised by poor microbiological quality of the food and poor hygiene practices that pose a risk to consumer health. The aim of the study was to evaluate the hygiene of surfaces in food trucks (FT) using the reference method together with alternatives such as Petrifilm^TM and the bioluminescence method. TVC, S. aureus, Enterobacteriaceae, E. coli, L. monocytogenes, and Salmonella spp. were assessed. The material for the study consisted of swabs and prints taken from five surfaces (refrigeration, knife, cutting board, serving board, and working board) in 20 food trucks in Poland. In 13 food trucks, the visual assessment of hygiene was very good or good, but in 6 FTs, TVC was found to exceed log 3 CFU/100 cm² on various surfaces. The assessment of surface hygiene using various methods in the food trucks did not demonstrate the substitutability of culture methods. Petrifilm^TM tests were shown to be a convenient and reliable tool for the monitoring of mobile catering hygiene. No correlation was found between the subjective visual method and the measurement of adenosine 5-triphosphate. In order to reduce the risk of food infections caused by bacteria in food trucks, it is important to introduce detailed requirements for the hygiene practices used in food trucks, including techniques for monitoring the cleanliness of surfaces coming into contact with food, in particular cutting boards and work surfaces. Efforts should be focused on introducing mandatory, certified training for food truck personnel in the field of microbiological hazards, appropriate methods of hygienisation, and hygiene monitoring. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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12 pages, 2415 KiB

Open AccessArticle

Accurate Detection of Salmonella Based on Microfluidic Chip to Avoid Aerosol Contamination

by Yining Luo, Shan Shan, Shuanglong Wang, Jinlin Li, Daofeng Liu and Weihua Lai

Foods 2022, 11(23), 3887; https://doi.org/10.3390/foods11233887 - 1 Dec 2022

Cited by 14 | Viewed by 2496

Abstract

Salmonella is a type of common foodborne pathogen of global concern, seriously endangering human health. In molecular biological detection of Salmonella, the method of amplifying DNA often faces the problem of aerosol pollution. In this study, a microfluidic chip was developed to [...] Read more.

Salmonella is a type of common foodborne pathogen of global concern, seriously endangering human health. In molecular biological detection of Salmonella, the method of amplifying DNA often faces the problem of aerosol pollution. In this study, a microfluidic chip was developed to integrate loop-mediated isothermal amplification (LAMP) and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a system to detect Salmonella. The LAMP reaction solution was initially injected into the chamber to amplify at 65 °C for 20 min; the CRISPR/Cas12a reaction solution was subsequently injected to mix with the amplicons for fluorescent signal production at 43 °C for 30 min. Then, the results can be confirmed by naked eyes under 495 nm light or by a fluorescence immunochromatographic reader. The detection limit of this method for Salmonella DNA was 118 pg/μL. The sensitivity and specificity of this method was 100%. Furthermore, this method was used to detect Salmonella after enrichment for 4 h in salmon and chicken samples spiked with 30 CFU/25 g, and was verified to have a stable detection capability in real samples. The microfluidic chip integrated with the LAMP and CRISPR/Cas12a system not only provides a possibility of highly sensitive endpoint fluorescent visual detection of a foodborne pathogen, but also greatly eliminates the risk of aerosol contamination. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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13 pages, 1544 KiB

Open AccessArticle

Quantitative Risk Assessment of Susceptible and Ciprofloxacin-Resistant Salmonella from Retail Pork in Chiang Mai Province in Northern Thailand

by Chaiwat Pulsrikarn, Anusak Kedsin, Parichart Boueroy, Peechanika Chopjitt, Rujirat Hatrongjit, Piyarat Chansiripornchai, Nipattra Suanpairintr and Suphachai Nuanualsuwan

Foods 2022, 11(19), 2942; https://doi.org/10.3390/foods11192942 - 20 Sep 2022

Cited by 1 | Viewed by 2527

Abstract

The adverse human health effects as a result of antimicrobial resistance have been recognized worldwide. Salmonella is a leading cause of foodborne illnesses while antimicrobial resistant (AMR) Salmonella has been isolated from foods of animal origin. The quantitative risk assessment (RA) as part [...] Read more.

The adverse human health effects as a result of antimicrobial resistance have been recognized worldwide. Salmonella is a leading cause of foodborne illnesses while antimicrobial resistant (AMR) Salmonella has been isolated from foods of animal origin. The quantitative risk assessment (RA) as part of the guidelines for the risk analysis of foodborne antimicrobial resistance was issued by the Codex Alimentarius Commission more than a decade ago. However, only two risk assessments reported the human health effects of AMR Salmonella in dry-cured pork sausage and pork mince. Therefore, the objective of this study was to quantitatively evaluate the adverse health effects attributable to consuming retail pork contaminated with Salmonella using risk assessment models. The sampling frame covered pork at the fresh market (n = 100) and modern trade where pork is refrigerated (n = 50) in Chiang Mai province in northern Thailand. The predictive microbiology models were used in the steps where data were lacking. Susceptible and quinolone-resistant (QR) Salmonella were determined by antimicrobial susceptibility testing and the presence of AMR genes. The probability of mortality conditional to foodborne illness by susceptible Salmonella was modeled as the hazard characterization of susceptible and QR Salmonella. For QR Salmonella, the probabilistic prevalences from the fresh market and modern trade were 28.4 and 1.9%, respectively; the mean concentrations from the fresh market and modern trade were 346 and 0.02 colony forming units/g, respectively. The probability of illness (P_I) and probability of mortality given illness (P_MI) from QR Salmonella-contaminated pork at retails in Chiang Mai province were in the range of 2.2 × 10⁻⁸–3.1 × 10⁻⁴ and 3.9 × 10⁻¹⁰–5.4 × 10⁻⁶, respectively, while those from susceptible Salmonella contaminated-pork at retails were in the range 1.8 × 10⁻⁴–3.2 × 10⁻⁴ and 2.3 × 10⁻⁷–4.2 × 10⁻⁷, respectively. After 1000 iterations of Monte Carlo simulations of the risk assessment models, the annual mortality rates for QR salmonellosis simulated by the risk assessment models were in the range of 0–32, which is in line with the AMR adverse health effects previously reported. Therefore, the risk assessment models used in both exposure assessment and hazard characterization were applicable to evaluate the adverse health effects of AMR Salmonella spp. in Thailand. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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14 pages, 2142 KiB

Open AccessArticle

Use of Large-Scale Genomics to Identify the Role of Animals and Foods as Potential Sources of Extraintestinal Pathogenic Escherichia coli That Cause Human Illness

by Lucas Harrison, Gregory H. Tyson, Errol Strain, Rebecca L. Lindsey, Nancy Strockbine, Olgica Ceric, Gamola Z. Fortenberry, Beth Harris, Sheryl Shaw, Glenn Tillman, Shaohua Zhao and Uday Dessai

Foods 2022, 11(13), 1975; https://doi.org/10.3390/foods11131975 - 3 Jul 2022

Cited by 5 | Viewed by 3327

Abstract

Extraintestinal pathogenic Escherichia coli (ExPEC) cause urinary tract and potentially life-threatening invasive infections. Unfortunately, the origins of ExPEC are not always clear. We used genomic data of E. coli isolates from five U.S. government organizations to evaluate potential sources of ExPEC infections. Virulence [...] Read more.

Extraintestinal pathogenic Escherichia coli (ExPEC) cause urinary tract and potentially life-threatening invasive infections. Unfortunately, the origins of ExPEC are not always clear. We used genomic data of E. coli isolates from five U.S. government organizations to evaluate potential sources of ExPEC infections. Virulence gene analysis of 38,032 isolates from human, food animal, retail meat, and companion animals classified the subset of 8142 non-diarrheagenic isolates into 40 virulence groups. Groups were identified as low, medium, and high relative risk of containing ExPEC strains, based on the proportion of isolates recovered from humans. Medium and high relative risk groups showed a greater representation of sequence types associated with human disease, including ST-131. Over 90% of food source isolates belonged to low relative risk groups, while >60% of companion animal isolates belonged to medium or high relative risk groups. Additionally, 18 of the 26 most prevalent antimicrobial resistance determinants were more common in high relative risk groups. The associations between antimicrobial resistance and virulence potentially limit treatment options for human ExPEC infections. This study demonstrates the power of large-scale genomics to assess potential sources of ExPEC strains and highlights the importance of a One Health approach to identify and manage these human pathogens. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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14 pages, 1231 KiB

Open AccessArticle

Detection of Resistant and Enterotoxigenic Strains of Staphylococcus warneri Isolated from Food of Animal Origin

by Ivana Regecová, Jana Výrostková, František Zigo, Gabika Gregová, Monika Pipová, Pavlina Jevinová and Jana Becová

Foods 2022, 11(10), 1496; https://doi.org/10.3390/foods11101496 - 20 May 2022

Cited by 10 | Viewed by 3649

Abstract

The topic of this work is the detection of antimicrobial resistance to Staphylococcus warneri strains and the genes encoding staphylococcal enterotoxins. It is considered a potential pathogen that can cause various—mostly inflammatory—diseases in immunosuppressed patients. The experimental part of the paper deals with [...] Read more.

The topic of this work is the detection of antimicrobial resistance to Staphylococcus warneri strains and the genes encoding staphylococcal enterotoxins. It is considered a potential pathogen that can cause various—mostly inflammatory—diseases in immunosuppressed patients. The experimental part of the paper deals with the isolation of individual isolates from meat samples of Oryctolagus cuniculus, Oncorhynchus mykiss, Scomber scombrus, chicken thigh, beef thigh muscle, pork thigh muscle, and bryndza cheese. In total, 45 isolates were obtained and subjected to phenotypic (plasma coagulase activity, nuclease, pigment, hemolysis, lecithinase, and lipase production) and genotypic analyses to confirm the presence of the S. warneri species. The presence of genes encoding staphylococcal enterotoxins A (three isolates) and D (six isolates) was determined by PCR. Using the Miditech system, the minimum inhibitory concentration for various antibiotics or antibiotics combinations was determined, namely for ampicillin; ampicillin + sulbactam; oxacillin; cefoxitin; piperacillin + tazobactam; erythromycin; clindamycin; linezolid; rifampicin; gentamicin; teicoplanin; vancomycin; trimethoprim; chloramphenicol; tigecycline; moxifloxacin; ciprofloxacin; tetracycline; trimethoprim + sulfonamide; and nitrofurantoin. Resistance to ciprofloxacin and tetracycline was most common (73%). At the same time, out of a total of 45 isolates, 22% of the isolates were confirmed as multi-resistant. Isolates that showed phenotypic resistance to β-lactam antibiotics were subjected to mecA gene detection by PCR. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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19 pages, 1164 KiB

Open AccessArticle

Comparison of Selected Phenotypic Features of Persistent and Sporadic Strains of Listeria monocytogenes Sampled from Fish Processing Plants

by Natalia Wiktorczyk-Kapischke, Ewa Wałecka-Zacharska, Krzysztof Skowron, Agnieszka Kijewska, Zuzanna Bernaciak, Justyna Bauza-Kaszewska, Zuzanna Kraszewska and Eugenia Gospodarek-Komkowska

Foods 2022, 11(10), 1492; https://doi.org/10.3390/foods11101492 - 20 May 2022

Cited by 8 | Viewed by 2704

Abstract

(1) Background: The main source of transmission of Listeria monocytogenes is contaminated food, e.g., fish and meat products and raw fruit and vegetables. The bacteria can remain for 13 years on machines in food processing plants, including fish plants. (2) Methods: A total [...] Read more.

(1) Background: The main source of transmission of Listeria monocytogenes is contaminated food, e.g., fish and meat products and raw fruit and vegetables. The bacteria can remain for 13 years on machines in food processing plants, including fish plants. (2) Methods: A total of 720 swabs were collected from a salmon filleting line. The research material consisted of 62 (8.6%) L. monocytogenes isolates. Pulsed Field Gel Electrophoresis (PFGE) allowed detecting a pool of persistent strains. All persistent strains (n = 6) and a parallel group of strains collected sporadically (n = 6) were characterized by their ability to invade HT-29 cells, biofilm formation ability, and minimum bactericidal concentrations (MBC) of selected disinfectants. (3) Results: Among the obtained isolates, 38 genetically different strains were found, including 6 (15.8%) persistent strains. The serogroup 1/2a-3a represented 28 strains (73.7%), including the persistent ones. There were no significant differences in invasiveness between the persistent and sporadic strains. The persistent strains tolerated higher concentrations of the tested disinfectants, except for iodine-based compounds. The persistent strains initiated the biofilm formation process faster and formed it more intensively. (4) Conclusions: The presence of persistent strains in the food processing environment is a great challenge for producers to ensure consumer safety. This study attempts to elucidate the phenotypic characteristics of persistent L. monocytogenes strains. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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8 pages, 250 KiB

Open AccessArticle

Insight into Bacillus cereus Associated with Infant Foods in Beijing

by Ping Wang, Xiaomei Zhao, Tianming Qu, Lijiao Liang, Qinglong Ji and Ying Chen

Foods 2022, 11(5), 719; https://doi.org/10.3390/foods11050719 - 28 Feb 2022

Cited by 9 | Viewed by 2853

Abstract

This study was undertaken to investigate the prevalence, antimicrobial resistance, and virulence gene profiles of Bacillus cereus in different brands of infant formula in Beijing supermarkets. Eighty-eight Bacillus cereus isolates were recovered in sixty-eight infant formulas of five domestic brands and fourteen imported [...] Read more.

This study was undertaken to investigate the prevalence, antimicrobial resistance, and virulence gene profiles of Bacillus cereus in different brands of infant formula in Beijing supermarkets. Eighty-eight Bacillus cereus isolates were recovered in sixty-eight infant formulas of five domestic brands and fourteen imported brands. The prevalence rate in domestic and imported samples were 70.6% and 52.9%, respectively. Lower mean prevalence level was found in domestic samples (1.17 MPN/g) compared with the imported samples (3.52 MPN/g). Twenty-four virulence gene profiles were found, and most strains carried at least one virulence gene. The prevalence of nheA, nheB, nheC, cytK, bceT, and entFM in domestic and imported brand samples was similar. The occurrence of enterotoxin genes hblA, hblC, and hblD in domestic samples were 22.2%, 27.8%, and 22.2%, respectively, which was significantly higher than imported samples. Antimicrobial drugs-susceptibility analysis showed that all isolates were susceptible to gentamincin, amikacin, and ciprofloxacin; 38%, 7%, and 2.3% were resistant to rifampin, tetracycline, and chloramphenicol, respectively; and only one isolate was resistant to trimethoprim-sulfamethoxazole. Moreover, the cell numbers of Bacillus cereus in prepared infant formula increased rapidly at room temperature. Thus, monitoring guidelines are needed for accepted levels of Bacillus cereus in infant formula. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

16 pages, 2913 KiB

Open AccessArticle

Developing Qualitative Plasmid DNA Reference Materials to Detect Mechanisms of Quinolone and Fluoroquinolone Resistance in Foodborne Pathogens

by Qinya Niu, Xiumin Su, Luxin Lian, Jinling Huang, Shutong Xue, Wei Zhou, Hongyang Zhao, Xing’an Lu, Shenghui Cui, Jia Chen and Baowei Yang

Foods 2022, 11(2), 154; https://doi.org/10.3390/foods11020154 - 7 Jan 2022

Cited by 3 | Viewed by 2449

Abstract

The aim of this study was to develop homogeneous and stable plasmid DNA reference materials for detecting the mechanisms of resistance to quinolones and fluoroquinolones in foodborne pathogens. The DNA fragments of 11 target genes associated with quinolone and fluoroquinolone resistance were artificially [...] Read more.

The aim of this study was to develop homogeneous and stable plasmid DNA reference materials for detecting the mechanisms of resistance to quinolones and fluoroquinolones in foodborne pathogens. The DNA fragments of 11 target genes associated with quinolone and fluoroquinolone resistance were artificially synthesized, inserted into plasmid vectors, and transferred into recipient cells. PCR and sequencing of DNA were performed to assess the genetic stability of the target DNA in recombinant Escherichia coli DH5α cells during subculturing for 15 generations. The limit of detection (LOD) of the target DNA was determined using PCR and real-time qualitative PCR (qPCR). The homogeneity and storage stability of plasmid DNA reference materials were evaluated in terms of plasmid DNA quantity, PCR-measured gene expression, and qPCR threshold cycle. All 11 target DNAs were successfully synthesized and inserted into vectors to obtain recombinant plasmids. No nucleotide mutations were identified in the target DNA being stably inherited and detectable in the corresponding plasmids during subculturing of recombinant strains. When the target DNA was assessed using PCR and qPCR, the LOD was ≤1.77 × 10⁵ and 3.26 × 10⁴ copies/μL, respectively. Further, when the reference materials were stored at 37 °C for 13 days, 4 °C for 90 days, and −20 °C for 300 days, each target DNA was detectable by PCR, and no mutations were found. Although the threshold cycle values of qPCR varied with storage time, they were above the LOD, and no significant differences were found in the quantity of each plasmid DNA at different timepoints. Further, the homogeneity and stability of the materials were highly consistent with the requirements of standard reference materials. To summarize, considering that our plasmid DNA reference materials conformed to standard requirements, they can be used to detect the mechanisms of quinolone and fluoroquinolone resistance in foodborne pathogens. Full article

(This article belongs to the Special Issue Detection, Control, Risk Assessment, and Prevention of Foodborne Microorganisms)

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