Foodborne Pathogens In Foods Research Articles

Recent advances in foodborne pathogen detection using photoelectrochemical biosensors: from photoactive material to sensing strategy

Rapid assessment and prevention of diseases caused by foodborne pathogens is one of the existing food safety regulatory issues faced by various countries, and it has received wide attention from all sectors of society. When the content of foodborne pathogens in food is higher than the limit standard and spreads in a certain way, it can cause disease outbreaks, which seriously threaten human health or life safety. Developing a novel method to detect foodborne pathogens accurately and rapidly is significant. Because of the limitations of complex steps, time-consuming, low sensitivity or poor selectivity of commonly used methods, a photoelectrochemical (PEC) biosensor based on electrochemistry is developed. Its advantages include a low background signal, fast response and simple operation. It also has broad application prospects for sensing, which has attracted wide attention. However, an organized summary of the latest PEC biosensors for foodborne pathogen sensing has not been reported. Therefore, this review introduces the recent advances in foodborne pathogen detection using PEC biosensors as follows: (i) the construction of PEC biosensors, (ii) the research status of PEC biosensors for the detection of foodborne pathogens and (iii) the direction of future development in this field. Hopefully, the study will provide some insight into developing more mature bio-sensing strategies to meet the practical needs of foodborne pathogen surveillance.

Imprinted membrane-covalent organic framework platform for efficient label-free visual detection of Listeria monocytogenes and Salmonella typhimurium in food samples

BackgroundRapid and sensitive detection of foodborne pathogens in food plays a crucial role in controlling outbreaks of foodborne diseases, of which Listeria monocytogenes and Salmonella typhimurium are representative and notable pathogens. Thus, it's of great importance to achieve the effective detection of these pathogens. However, the most common detection methods (culture-based technique, Polymerase Chain Reaction and immunological methods) have disadvantages that cannot be ignored, such as time-consuming, laborious, complex sample preparation process, and the possibility of cross-reaction. Hence, it is essential to develop a facile detection method for the pathogens with high sensitivity and specificity to avoid the above-mentioned disadvantages. ResultsWe report a label-free visual platform for the simultaneous capture and detection of Listeria monocytogenes and Salmonella typhimurium. For the first time, we have prepared polydimethylsiloxane-Chromotrope 2R membrane which serves as the substrate for bacterial capture and enrichment through the formation of specific recognition sites. The positively charged Pt-covalent organic framework combines with the pathogens through surface charge interaction, thereby the label-free sandwich platform is formed. Remarkable peroxidase activity of Pt-covalent organic framework converts the conversion of bacterial quantity into amplified color signal by catalyzing 3,3′,5,5′-Tetramethylbenzidine to oxidized 3,3′,5,5′-Tetramethylbenzidine. The platform demonstrates the capability to identify two representative food-borne pathogens within a time frame of 100 min, exhibiting high sensitivity and excellent specificity without the interference from non-target bacteria. The limit of detection of the visual platform toward Listeria monocytogenes and Salmonella typhimurium was 1.61 CFU mL−1 and 1.31 CFU mL−1, respectively. And the limit of quantification toward Listeria monocytogenes and Salmonella typhimurium was 4.94 CFU mL−1 and 2.47 CFU mL−1, respectively. The relative standard derivations of the visual platform for both bacteria were lower than 4.9 %. Furthermore, our proposed platform has obtained reliable and satisfactory results on analyzing diverse food samples. SignificanceThis research expands the application of a label-free platform combined with unlabeled nanocomponents in the rapid isolation and detection of diverse of food-borne pathogens. The platform possesses the advantages of simple operation and real-time monitoring, without complicated sample pretreatment process. The whole detection process can realize the simultaneous monitoring of Listeria monocytogenes and Salmonella typhimurium within 100 min. Furthermore, it is also of reference significance for the detection of other common pathogens.

Isolation, characterization and application of a novel polyvalent bacteriophage SF02 for the control of Salmonella and Escherichia coli O157:H7 in foods

Salmonella and E. coli O157:H7 are two important foodborne pathogens that present a significant peril to human health. Recently, bacteriophages have attracted attention as a new type of bacteriostatic agents. In this study, a polyvalent phage named SF02 was isolated and purified, the morphology, biological characteristics, host range, and complete genome sequence of the phage were analyzed. The results indicated that phage SF02 is a long-tailed phage and belongs to the family of Ackermannviridae, and with no toxin and antibiotic resistance genes. The host range showed that SF02 had lytic activity against 33 strains of Salmonella out of 42 strains, and also had lytic activity against E. coli O157:H7. In addition, It also stable at temperature ranging from 30～60 °C and pH values from 3～11. The SF02 with a relatively short latent period of 15 min and a burst size of 94 and 63 PFU/infected cells in Salmonella and E. coli O157:H7, respectively. Furthermore, Viable Salmonella and E. coli O157:H7 were significantly reduced in ready-to-eat chicken claw and pork loin after treatment with SF02 at 4 °C for 10 h. In summary, these results suggest that the SF02 has potential as a candidate for controlling foodborne pathogens in food.

An Argonaute-mediated bio-barcode bioassay for one-tube and on-site detection of Staphylococcus aureus

Isothermal amplification method has enabled major advancement toward rapid and deployable detection for nucleic acid. While exciting, there are still a series of deficiencies facing their practical implementation, such as carryover cross-contamination, which are major bottlenecks that must be addressed. In addition, there is a lack of high-throughput detection for foodborne pathogens in foods. Here, we reported an Argonaute-mediated bio-barcode bioassay for one-step cleavage, on-site and high-throughput detection of S. aureus (Staphylococcus aureus) through introducing Tag sequence and recombinase aided amplification (RAA). Furthermore, we designed a single vessel via tube-in-tube manner for one-tube contamination-free and portable detection without opening the lid. With this strategy, the same detection limit as fluorescence detection could be obtained, 1 CFU/mL with high specificity for S. aureus. We further evaluated the performance of bio-barcode biosensing strategy using S. aureus-contaminated clinical and food samples. Argonaute-mediated bio-barcode bioassay had the advantages of modular, universal plug-and-play and high-throughput scanning. This work not only satisfied the requirement for convenient detection but also fulfilled the need for portable on-site nucleic acid detection with portability, adaptability, transferability and practicality.

Analysis on Foodborne Pathogen Contamination of Food Samples in Longnan City from 2013 to 2022.

The objective was to determine the prevalence of foodborne pathogens in food in Longnan City, Gansu Province, China. In this research, we conducted tests on baked foods, catering foods, meat, and fruits and vegetables sold in supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens from 2013 to 2022. We analyzed the variety of foodborne pathogens (Salmonella, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and diarrheagenic Escherichia coli) in different sites and food types. Once foodborne pathogens were detected in the sample, it was deemed unqualified. The total detection rates of foodborne pathogens were 1.559%, 3.349%, 1.980%, 1.040%, 3.383%, and 1.303% in food from supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens, respectively. No pathogenic bacteria were detected in baked foods. Salmonella, S. aureus, L. monocytogenes, B. cereus, and diarrheagenic E. coli were detected in catering foods, among which B. cereus had the highest detection rate. Salmonella was the most common pathogenic bacteria detected in meat, while the detection rate of pathogenic bacteria in fruits and vegetables was low, with only one positive sample for diarrheagenic E. coli. Among the six sites, street stalls (3.382%) and farmers' markets (3.349%) had higher detection rates of pathogens. In general, the detection rate of pathogens from 2013 to 2022 was not high, but there were also some hidden dangers. Catering food is vulnerable to pathogen contamination, and street stalls and farmers' markets are the main sites of pollution. According to the above findings, the regulatory authorities should continue to strengthen supervision, guarantee food safety through early warning, and reduce the risk of food contamination.

Bioactive Paper Packaging for Extended Food Shelf Life

Food safety and quality are major problems for food producers and industry, governments, and consumers. Conventional plastic-based food packaging is difficult to dispose of and recycle due to its provenience from fossil resources and resistance to biodegradation. Therefore, currently, the trend is to develop new eco-friendly food packaging that can replace these materials. The limitations of conventional packaging can be solved by developing new active materials with antimicrobial and antioxidant properties, based on cellulose, a natural biodegradable organic compound derived from renewable resources. In this study, new materials with antioxidant and antibacterial activity were obtained by combining a “green” functionalization approach (enzymatic activation) and surface modification using bioactive agents (essential clove oil and cold-pressed grape seed oil). Kraft paper was firstly activated with cellulase, followed by impregnation with the above-mentioned oil solutions, and then its properties were evaluated. The increased values of the O/C ratio for modified Kraft paper indicate an increased polarity due to the presence of phenolic groups. This resulted in an improved hydrophobicity, with the water contact angle increasing from 97° to over 110°. Following different interactions with the functional groups of vegetable oils, the modified Kraft paper exhibited distinct antioxidant and antibacterial properties. However, modified paper with clove essential oil showed higher antioxidant activity (due to the higher content of phenolic compounds), while modified paper with cold-pressed grape seed oil had better antimicrobial activity against Escherichia coli (−), Salmonella enteritidis (−), and Listeria monocytogenes (+) bacterial strains, and was more effective at reducing bacterial growth on fresh beef and fresh curd. The newly obtained bioactive paper provides an effective packaging material that can help control foodborne pathogens in food, thus extending its shelf life and safety.

Recent Advances in Electrochemical Biosensors for the Detection of Foodborne Pathogens: Current Perspective and Challenges.

Foodborne pathogens cause many diseases and significantly impact human health and the economy. Foodborne pathogens mainly include Salmonella spp., Escherichia coli, Staphylococcus aureus, Shigella spp., Campylobacter spp. and Listeria monocytogenes, which are present in agricultural products, dairy products, animal-derived foods and the environment. Various pathogens in many different types of food and water can cause potentially life-threatening diseases and develop resistance to various types of antibiotics. The harm of foodborne pathogens is increasing, necessitating effective and efficient methods for early monitoring and detection. Traditional methods, such as real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and culture plate, are time-consuming, labour-intensive and expensive and cannot satisfy the demands of rapid food testing. Therefore, new fast detection methods are urgently needed. Electrochemical biosensors provide consumer-friendly methods to quickly detect foodborne pathogens in food and the environment and achieve extensive accuracy and reproducible results. In this paper, by focusing on various mechanisms of electrochemical transducers, we present a comprehensive overview of electrochemical biosensors for the detection of foodborne pathogens. Furthermore, the review introduces the hazards of foodborne pathogens, risk analysis methods and measures of control. Finally, the review also emphasizes the recent research progress and solutions regarding the use of electrochemical biosensors to detect foodborne pathogens in food and the environment, evaluates limitations and challenges experienced during the development of biosensors to detect foodborne pathogens and discusses future possibilities.

Antimicrobial Activity of Syzygium polyanthum Wight (Walp.) Extract against Foodborne Pathogens in Food: A Potential Antimicrobial Agent for Natural Food Washing Solution

Developments of natural preservatives derived from plant sources instead of chemical preservatives are gaining more attention nowadays. In this study, the effect of Syzygium polyanthum (Wight) Walp.] leaves extract against foodborne pathogens on raw chicken meat and cherry tomato was evaluated using the method of washing treatment by extract solution. Results found that Syzygium polyanthum (Wight) Walp. leaves extract have significant effect (P <0.05) in reduction of foodborne pathogens in all tested food samples at 5 mg/mL of extract for 5 min soaking period. Moreover, S. polyanthum extract (10 mg/ml and 50 mg/ml) able to reduce yeast, mould and E. coli in raw meat chicken after storing at 4 ± 2°C for 5 days and reduce Pseudomonas species in cherry tomato after storing for 15 days at 4 ± 2°C. Antimicrobial property of S. polyanthum might be due to the presence of pyrogallol, β-Sitosterol, phytol, hexadecanoic acid, gallic acid, bergenin, quercetin 3-(6''-galloylgalactoside), madecassic acid, quillaic acid and asiatic acid that were detected by GC-MS and LC-MS. In conclusion, S. polyanthum extract exhibited antimicrobial activity, thus it has potential to be developed as antimicrobial agent for natural food washing solution.

An ultrasensitive electrochemical aptasensor using Tyramide-assisted enzyme multiplication for the detection of Staphylococcus aureus

In this study, we aimed to introduce a new electrochemical aptasensor based on the tyramide signal amplification (TSA) technology for a highly-sensitive detection of the pathogenic bacterium, Staphylococcus aureus, as a model of foodborne pathogens. In this aptasensor, the primary aptamer, SA37, was used to specifically capture bacterial cells; the secondary aptamer, SA81@HRP, was used as the catalytic probe; and a TSA-based signal enhancement system comprising of biotinyl-tyramide and streptavidin-HRP as electrocatalytic signal tags was adopted to fabricate the sensor and improve the detection sensitivity. S. aureus cells were selected as the pathogenic bacteria to verify the analytical performance of this TSA-based signal-enhancement electrochemical aptasensor platform. After the simultaneous binding of SA37-S. aureus-SA81@HRP formed on the gold electrode, thousands of @HRP molecules could be bound onto the biotynyl tyramide (TB) displayed on the bacterial cell surface through a catalytic reaction between HRP and H2O2, resulting in the generation of the highly amplified signals mediated by HRP reactions. This developed aptasensor could detect S. aureus bacterial cells at an ultra-low concentration, with a limit of detection (LOD) of 3 CFU/mL in buffer. Furthermore, this chronoamperometry aptasensor successfully detected target cells in both tap water and beef broth with LOD to be 8 CFU/mL, which are very high sensitivity and specificity. Overall, this electrochemical aptasensor using TSA-based signal-enhancement could be a very useful tool for the ultrasensitive detection of foodborne pathogens in food and water safety and environmental monitoring.

Functionalized magnetic nanobeads for SERS-based detection of Staphylococcus aureus.

In this study, we introduced a Raman detection technique based on a combination of functionalized magnetic beads and surface-enhanced Raman scattering (SERS) tags to develop a rapid and sensitive strategy for the detection of Staphylococcus aureus (S. aureus), a typical foodborne pathogen. Polyethylene glycol (PEG) and bovine serum albumin (BSA) dual-mediated teicoplanin functionalized magnetic beads (TEI-BPBs) were prepared for separation of target bacteria. SERS tags were used to immobilize antibodies on gold surfaces with bifunctional linker proteins to ensure specific recognition of S. aureus. Under optimal conditions, the combination of TEI-BPBs and SERS tags showed reliable performance, exhibiting good capture efficiency even in the presence of 106 CFU mL-1 of non-target bacteria. The SERS tag provided an effective hot spot for subsequent Raman detection, presenting good linearity in the range of 102-107 CFU mL-1. Good performance has also been shown in detecting target bacteria in milk samples, where it has a recovery of 95.5-101.3%. Thus, the highly sensitive Raman detection technique combined with TEI-BPBs capture probes and SERS tags is a promising method for the detection of foodborne pathogens in food or clinical samples.

Advances in magnetic nanoparticles for the separation of foodborne pathogens: Recognition, separation strategy, and application.

Foodborne pathogens contamination is one of the main sources of food safety problems. Although the existing detection methods have been developed for a long time, the complexity of food samples is still the main factor affecting the detection time and sensitivity, and the rapid separation and enrichment of pathogens is still an objective to be studied. Magnetic separation strategy based on magnetic nanoparticles (MNPs) is considered to be an effective tool for rapid separation and enrichment of foodborne pathogens in food. Therefore, this study comprehensively reviews the development of MNPs in the separation of foodborne pathogens over the past decade. First, various biorecognition reagents for identification of foodborne pathogens and their modifications on the surface of MNPs are introduced. Then, the factors affecting the separation of foodborne pathogens, including the size of MNPs, modification methods, separation strategies and separation forms are discussed. Finally, the application of MNPs in integrated detection methods is reviewed. Moreover, current challenges and prospects of MNPs for the analysis of foodborne pathogens are discussed. Further research should focus on the design of multifunctional MNPs, the processing of large-scale samples, the simultaneous analysis of multiple targets, and the development of all-in-one small analytical device with separation and detection.

Mesoporous ZnO@CO3O4 nanosphere for sensitive detection of 3-hydroxy-2-butanone

It is important to detect foodborne pathogens in food and water, such as Listeria monocytogenes (L.monocytrogenes), which can cause foodborne illness in people with compromised immune systems. Volatile organic compounds (VOC) and 3‑hydroxy-2-butanone (3H-2B) produced by L.monocytrogenes can be used as biomarkers for indirect detection of microbial contamination. In this study, the mesoporous ZnO@CO3O4 nanosphere was prepared through the simple hydrothermal synthesis method of ZIF-l-Zn@Co, the cage construction of mesoporous ZnO@CO3O4 nanosphere was remained unchanged after the calcination of the ZIF-l-Zn@Co at 600 °C for 2 h in air. The mesoporous ZnO@CO3O4 nanosphere was selected as the gas sensor showed the strongest response to 3H-2B, and 7–12 times higher than the response of other test gases. In addition, compared with ZnO and Co3O4 single metal oxide gas sensor, the ZnO@CO3O4 sensor possessed better repeatability and stability after repeated repeatability tests under the same conditions.

Dual recognition and highly sensitive detection of Listeria monocytogenes in food by fluorescence enhancement effect based on Fe3O4@ZIF-8-aptamer

A highly sensitive and selective foodborne pathogen detection system is essential to ensure food quality and public health. Therefore, in this study, a dual recognition and highly sensitive detection of Listeria monocytogenes by fluorescence enhancement strategy based on Fe3O4 @ZIF-8 have been developed. Aptamer absorbed on Fe3O4 @ZIF-8 were used for the specific capture of Listeria monocytogenes, and the conjugates of anti-Listeria monocytogenes antibody-biotin and streptavidin-FITC were used as signal amplification and fluorescence recognition probes binding with target bacteria. Simultaneously, the quantitative detection of Listeria monocytogenes was realized by monitoring the increase of FITC fluorescence signal due to hydrophobic environment. The linear range of the detection of pure culture was from 1.4 × 101 to 1.4 × 107 CFU/mL, with the detection limits as low as 0.88 CFU/mL and the coefficient of variation of each concentration no more than 2%. A good specificity of the detection system was also showed in the results, and the detection took about 70 min. Furthermore, the spiked samples of pork and milk were also tested by the detection system, and the recoveries ranged from 88.0% to 103.8%, with the coefficient of variation less than 12.8%. Taking advantages of sensitivity, rapidly and good selectivity, the proposed strategy in this study has great application potential in detection of foodborne pathogens in food.

Antimicrobial activity of Rhus Coriaria L. and Salvia Urmiensis bunge against some food-borne pathogens and identification of active components using molecular networking and docking analyses

This research aimed to evaluate the in vitro antibacterial activity of methanol extracts of Rhus coriaria L. (sumac) and Salvia urmiensis Bunge against some food-borne pathogens, survey the phytochemical constituents of the extracts, and their activity against some drug targets in pathogens. The antibacterial activity of the extracts was evaluated against six pathogens using agar well diffusion and broth microdilution methods. Both extracts exhibited antibacterial activity and the highest activity was obtained by sumac against Staphylococcus aureus (27.7 ± 0.8 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of sumac against tested bacteria were in the range of 0.125-0.5 and 0.25-1 mg/mL, respectively. S. urmiensis showed weaker antimicrobial activity with a MIC range of 2-4 mg/mL. A molecular networking analysis of extracts resulted in annotation of 18 and 12 compounds from the methanol extracts of S. urmiensis and sumac respectively, which mainly were related to flavonoids. Molecular docking analysis could effectively characterize some glycosylated flavonoids with a high binding affinity to the studied enzymes. This study confirmed the efficacy of sumac and S. urmiensis extracts as natural antimicrobial agents and introduced a wide range of compounds, which can be used in food preservation to control foodborne pathogens in food.

Evaluation of the use of ampicillin‐ and streptomycin‐resistant Shiga toxin‐producing Escherichia coli to reduce the burden of background microbiota during food safety studies

AbstractTracking artificially seeded foodborne pathogens in foods with high background microbiota is challenging. Wheat flour and its subsidiary products are known to carry a high native microbial load, which could interfere with tracking and enumeration of target organisms in such matrices. Shiga toxin‐producing Escherichia coli (STEC) serogroups O26, O121, and O157:H7 were transformed with the pGFPuv plasmid encoding ampicillin resistance (+Amp) and green fluorescent protein and were additionally conferred resistance to streptomycin (+Amp + Strep) through exposure to incremental concentrations of the antibiotic. Growth characteristics of these antibiotic‐resistant strains were compared to those of the nonresistant native strains (NR). The supplementation of ampicillin and ampicillin + streptomycin in growth media was evaluated for its ability to suppress growth of the native microbial load of three different commercial cake mixes. Antibiotic supplementation in growth media was successful in suppressing the native microbiota of the cake mixes, while the growth characteristics of the +Amp + Strep variants of the three STEC strains did not differ significantly from the NR strains (p > .05). These results indicate that STEC strains with ampicillin and streptomycin resistance markers have improved trackability over their wild‐type counterparts when isolated from food matrices with high background microbiota. These strains would be advantageous for use in laboratory experiments on STEC survival in wheat and wheat derived products as their detection and enumeration can occur without interference from native microbial load.

Guidance on validation of lethal control measures for foodborne pathogens in foods.

Food manufacturers are required to obtain scientific and technical evidence that a control measure or combination of control measures is capable of reducing a significant hazard to an acceptable level that does not pose a public health risk under normal conditions of distribution and storage. A validation study provides evidence that a control measure is capable of controlling the identified hazard under a worst-case scenario for process and product parameters tested. It also defines the critical parameters that must be controlled, monitored, and verified during processing. This review document is intended as guidance for the food industry to support appropriate validation studies, and aims to limit methodological discrepancies in validation studies that can occur among food safety professionals, consultants, and third-party laboratories. The document describes product and process factors that are essential when designing a validation study, and gives selection criteria for identifying an appropriate target pathogen or surrogate organism for a food product and process validation. Guidance is provided for approaches to evaluate available microbiological data for the target pathogen or surrogate organism in the product type of interest that can serve as part of the weight of evidence to support a validation study. The document intends to help food manufacturers, processors, and food safety professionals to better understand, plan, and perform validation studies by offering an overview of the choices and key technical elements of a validation plan, the necessary preparations including assembling the validation team and establishing prerequisite programs, and the elements of a validation report.

Sensitive detection of foodborne pathogens based on CRISPR-Cas13a.

Salmonella, being one of the most widespread foodborne pathogens, is a compulsory test item required by national food safety standard of China and many other countries. More sensitive and specific Salmonella detection method is still needed since traditional methods are time consuming and highly dependent on enormous manpower and material resources. In this research, a bacteria detection method based on CRISPR-Cas13a system (where CRISPR is Clustered Regularly Interspaced Short Palindromic Repeats) was proposed. The target DNA was amplified by PCR and transcribed into RNA by T7 transcriptase, which can activate the RNase activity of the Cas13a protein. The self-folding quenched fluorescent probe can be cleaved by the activated Cas13a protein to generate fluorescent signal. We named this method as PCF detection (PCR-CRISPR-Fluorescence based nucleic acid detection). In this study, PCF detection showed excellent sensitivity, which can detect Salmonella genomic DNA with a minimum of 101 aM or 10° CFU/ml Salmonella bacteria in 2hr. It also showed good specificity with no cross-reaction with other common foodborne bacteria. PRACTICAL APPLICATION: The PCF detection method proposed in this article can detect Salmonella sensitively and specifically, providing a novel strategy for the detection of foodborne pathogens in food and has great application potential in other microbial detection fields.

Research Progress on Detection of Foodborne Pathogens in Food Using Biosensors

Foodborne pathogens are one of the most main factors causing food safety problems. Traditional methods for detecting foodborne pathogens have drawbacks which have not only long detection time but also have poor specificity and sensitivity. Nowadays, with the progress and development of biological and electronic technology, many new detection methods have emerged. Biosensor is one of the technologies with broad application and market prospects. Using biosensor technology can achieve efficient, rapid and real-time detection and monitor of microorganisms in food, thereby it pioneers a new developing direction for the establishment of system to detect foodborne pathogens rapidly. This paper introduces the basic principles and classifications of biosensors, reviews the application and development of common and different biosensors in the detection of foodborne pathogens in food, compares their advantages and disadvantages, and summarizes existing development bottlenecks of commercialization and prospects for further trends.

Salmonella is the most common foodborne pathogen in African food exports to the European Union: Analysis of the Rapid Alert System for Food and Feed (1999–2019)

Global food imports, including those from Africa, constitute an integral part of the food chain in the European Union (EU) and a potential source of food hazards. Foodborne pathogens are among the food hazards that do not only impact on public health but also have economic implications for exporters. The Rapid Alert System for Food and Feed (RASFF) is an important tool for reporting and communicating food safety risks among EU Member States and EEA countries. This study aimed to identify the common foodborne pathogens in foods originating from African countries to the EU between 1999 and 2019 by analysing RASFF notifications. A total of 596 notifications were reported by 19 countries due to the presence of pathogenic microorganisms (PM) in food originating from 27 African countries. The highest number of notifications related to Greece (n = 228) and most of the PM notifications were border rejections (60.6%). PM notifications increased from 17 (2016) to 46 (2017) and 173 (2019). Salmonella was the most predominant pathogen notified, accounting for 523 (87.8%) of PM notifications. Over half (52%) of the Salmonella notifications were from foods originating from Eastern Africa, followed by Western Africa (n = 145; 28%), and the country with the highest Salmonella contamination was Sudan (n = 182). The most important product category contaminated with Salmonella was “nuts, nut products and seeds” (n = 343), with majority (n = 335) being sesame seeds. Evaluation of the RASFF risk decision listed for each notification showed that 97% of Salmonella-contaminated sesame seeds posed serious risks to consumers. African countries exporting food products to the EU must strengthen their food safety systems to prevent the huge economic losses resulting from non-compliance with EU food safety standards.

Development of a selective and differential media for the isolation and enumeration of Bacillus cereus from food samples.

Identification and enumeration of foodborne pathogens in food stuffs are valuable concerns. In the present study, starch-blood-egg yolk-polymyxin B-trimethoprim-ceftazidime (SBYPTC) agar was established to isolate and specify the number of Bacillus cereus in food products. The effectiveness of the developed medium in selecting for B. cereus from pure cultures and food matrixes naturally contaminated by high levels of microbiota was estimated, and the results were compared with that of two commercially available MYPA and PMBA media. In pure cultures, there were no significant differences in the recoverability of B. cereus among the three media, however, SBYPTC agar showed a greater exclusivity. To examine SBYPTC performance in food, B. cereus were artificially inoculated into lettuce and potato samples with high background microbiota in two separated experiments. There were no significant differences between MYPA and PEMBA. However, SBYPTC manifested greater selectivity and exclusivity and made the differentiation easier by allowing growth of B. cereus in separated colonies and inhibiting competing microflora. Our results showed that SBYPTC has high selective properties in comparison with MYPA and PEMBA. Thus, it can be considered as a useful tool to monitor the existence and the number of B. cereus in foods especially those contaminated with high levels of microflora. In the food industry, SBYPTC can be employed for food quality assurance to monitor B. cereus in food products contaminated with high levels of microbiota.