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1.
Nat Commun ; 15(1): 3893, 2024 May 08.
Article in English | MEDLINE | ID: mdl-38719799

ABSTRACT

Maintaining food safety and quality is critical for public health and food security. Conventional food preservation methods, such as pasteurization and dehydration, often change the overall organoleptic quality of the food products. Herein, we demonstrate a method that affects only a thin surface layer of the food, using beef as a model. In this method, Joule heating is generated by applying high electric power to a carbon substrate in <1 s, which causes a transient increase of the substrate temperature to > ~2000 K. The beef surface in direct contact with the heating substrate is subjected to ultra-high temperature flash heating, leading to the formation of a microbe-inactivated, dehydrated layer of ~100 µm in thickness. Aerobic mesophilic bacteria, Enterobacteriaceae, yeast and mold on the treated samples are inactivated to a level below the detection limit and remained low during room temperature storage of 5 days. Meanwhile, the product quality, including visual appearance, texture, and nutrient level of the beef, remains mostly unchanged. In contrast, microorganisms grow rapidly on the untreated control samples, along with a rapid deterioration of the meat quality. This method might serve as a promising preservation technology for securing food safety and quality.


Subject(s)
Food Microbiology , Food Preservation , Animals , Cattle , Food Preservation/methods , Food Microbiology/methods , Meat/microbiology , Hot Temperature , Red Meat/microbiology , Heating , Food Safety/methods
2.
Mikrochim Acta ; 191(6): 331, 2024 05 15.
Article in English | MEDLINE | ID: mdl-38744722

ABSTRACT

A broad host range phage-based nanozyme (Fe-MOF@SalmpYZU47) was prepared for colorimetric detection of multiple Salmonella enterica strains. The isolation of a broad host range phage (SalmpYZU47) capable of infecting multiple S. enterica strains was achieved. Then, it was directly immobilized onto the Fe-MOF to prepare Fe-MOF@SalmpYZU47, exhibiting peroxidase-like activity. The peroxidase-like activity can be specifically inhibited by multiple S. enterica strains, benefiting from the broad host range capture ability of Fe-MOF@SalmpYZU47. Based on it, a colorimetric detection approach was developed for S. enterica in the range from 1.0 × 102 to 1.0 × 108 CFU mL-1, achieving a low limit of detection (LOD) of 11 CFU mL-1. The Fe-MOF@SalmpYZU47 was utilized for detecting S. enterica in authentic food samples, achieving recoveries ranging from 91.88 to 105.34%. Hence, our proposed broad host range phage-based nanozyme exhibits significant potential for application in the colorimetric detection of pathogenic bacteria.


Subject(s)
Colorimetry , Limit of Detection , Metal-Organic Frameworks , Salmonella enterica , Colorimetry/methods , Salmonella enterica/isolation & purification , Salmonella enterica/chemistry , Metal-Organic Frameworks/chemistry , Food Microbiology/methods , Food Contamination/analysis , Peroxidase/chemistry
3.
Anal Chim Acta ; 1308: 342616, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38740451

ABSTRACT

BACKGROUND: Bacterial spores are the main potential hazard in medium- and high-temperature sterilized meat products, and their germination and subsequent reproduction and metabolism can lead to food spoilage. Moreover, the spores of some species pose a health and safety threat to consumers. The rapid detection, prevention, and control of bacterial spores has always been a scientific problem and a major challenge for the medium and high-temperature meat industry. Early and sensitive identification of spores in meat products is a decisive factor in contributing to consumer health and safety. RESULTS: In this study, we developed a novel and stable Ag@AuNP array substrate by using a two-step synthesis approach and a liquid-interface self-assembly method that can directly detect bacterial spores in actual meat product samples without the need for additional in vitro bacterial culture. The results indicate that the Ag@AuNP array substrate exhibits high reproducibility and Raman enhancement effects (1.35 × 105). The differentiation in the Surface enhanced Raman scattering (SERS) spectra of five bacterial spores primarily arises from proteins in the spore coat and inner membrane, peptidoglycan of cortex, and Ca2⁺-DPA within the spore core. The correct recognition rate of linear discriminant analysis for spores in the meat product matrix can reach 100 %. The average recovery accuracy of the SERS quantitative model was at around 101.77 %, and the limit of detection can reach below 10 CFU/mL. SIGNIFICANCE: It provides a promising technological strategy for the characteristic substance analysis and timely monitoring of spores in meat products.


Subject(s)
Meat Products , Silver , Spectrum Analysis, Raman , Spores, Bacterial , Spectrum Analysis, Raman/methods , Silver/chemistry , Spores, Bacterial/isolation & purification , Spores, Bacterial/chemistry , Meat Products/microbiology , Meat Products/analysis , Metal Nanoparticles/chemistry , Food Contamination/analysis , Surface Properties , Food Microbiology/methods , Cooking
4.
Sci Prog ; 107(2): 368504231223029, 2024.
Article in English | MEDLINE | ID: mdl-38773741

ABSTRACT

Contaminated fresh produce remains a prominent catalyst for food-borne illnesses, prompting the need for swift and precise pathogen detection to mitigate health risks. This paper introduces an innovative strategy for identifying food-borne pathogens in fresh produce samples from local markets and grocery stores, utilizing optical sensing and machine learning. The core of our approach is a photonics-based sensor system, which instantaneously generates optical signals to detect pathogen presence. Machine learning algorithms process the copious sensor data to predict contamination probabilities in real time. Our study reveals compelling results, affirming the efficacy of our method in identifying prevalent food-borne pathogens, including Escherichia coli (E. coli) and Salmonella enteric, across diverse fresh produce samples. The outcomes underline our approach's precision, achieving detection accuracies of up to 95%, surpassing traditional, time-consuming, and less accurate methods. Our method's key advantages encompass real-time capabilities, heightened accuracy, and cost-effectiveness, facilitating its adoption by both food industry stakeholders and regulatory bodies for quality assurance and safety oversight. Implementation holds the potential to elevate food safety and reduce wastage. Our research signifies a substantial stride toward the development of a dependable, real-time food safety monitoring system for fresh produce. Future research endeavors will be dedicated to optimizing system performance, crafting portable field sensors, and broadening pathogen detection capabilities. This novel approach promises substantial enhancements in food safety and public health.


Subject(s)
Escherichia coli , Food Microbiology , Machine Learning , Food Microbiology/methods , Escherichia coli/isolation & purification , Foodborne Diseases/microbiology , Foodborne Diseases/prevention & control , Food Safety/methods , Humans , Vegetables/microbiology , Food Contamination/analysis , Salmonella/isolation & purification
5.
Cell Mol Biol (Noisy-le-grand) ; 70(5): 33-39, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38814237

ABSTRACT

The study was conducted in the Kingdom of Saudi Arabia from 2020 and 2022. The identification, characterization, and evaluation of microbes found in hen eggs was done and it was found very important to prevent contamination caused by various harmful pathogenic microbes. It was found that contaminated eggs harbor various harmful microbes which affect health due to multiple infectious diseases. Hen eggs contain a wide variety of microbes, and several distinct approaches were utilized as well as available for achieving detailed pathogenic information. The information obtained is highly essential for people who consume eggs as a food product.  It is of the utmost importance to protect people from getting sick due to the consumption of contaminated eggs or eggs from chickens that have been infected by various harmful pathogens.  During the experiment, we found that eggs were contaminated directly or the chicken that laid the egg was contaminated. Using molecular genetic analysis, it is possible to detect pathogenic and non-pathogenic contaminations in eggs.  During present studies, the cutting-edge molecular techniques of 16S rRNA gene sequencing technology were used to carry out the objective of performing a molecular identification of the microbial communities infecting eggs. The present research is aimed at determining whether the microbial communities in hen eggs are harmful to humans. The results further indicated most bacteria have the potential to cause illness in humans including Escherichia fergusonii, Salmonella enterica, Pseudocitrobacter faecalis, Yakenella regensburgei, and Erwinia pyrifoliae. Further, research suggested that eggs need to be properly cooked and thoroughly washed to eliminate the possibility of consuming infected eggs.


Subject(s)
Chickens , Eggs , Microbiota , RNA, Ribosomal, 16S , Animals , Chickens/microbiology , Eggs/microbiology , Microbiota/genetics , RNA, Ribosomal, 16S/genetics , Bacteria/genetics , Bacteria/isolation & purification , Bacteria/classification , Humans , Saudi Arabia , Female , Food Microbiology/methods
6.
Compr Rev Food Sci Food Saf ; 23(3): e13362, 2024 05.
Article in English | MEDLINE | ID: mdl-38720585

ABSTRACT

Fermentation is a traditional method utilized for vegetable preservation, with microorganisms playing a crucial role in the process. Nowadays, traditional spontaneous fermentation methods are widely employed, which excessively depend on the microorganisms attached to the surface of raw materials, resulting in great difficulties in ideal control over the fermentation process. To achieve standardized production and improve product quality, it is essential to promote inoculated fermentation. In this way, starter cultures can dominate the fermentation processes successfully. Unfortunately, inoculated fermentation has not been thoroughly studied and applied. Therefore, this paper provides a systematic review of the potential upgrading strategy of vegetable fermentation technology. First, we disclose the microbial community structures and succession rules in some typical spontaneously fermented vegetables to comprehend the microbial fermentation processes well. Then, internal and external factors affecting microorganisms are explored to provide references for the selection of fermented materials and conditions. Besides, we widely summarize the potential starter candidates with various characteristics isolated from spontaneously fermented products. Subsequently, we exhibited the inoculated fermentation strategies with those isolations. To optimize the product quality, not only lactic acid bacteria that lead the fermentation, but also yeasts that contribute to aroma formation should be combined for inoculation. The inoculation order of the starter cultures also affects the microbial fermentation. It is equally important to choose a proper processing method to guarantee the activity and convenience of starter cultures. Only in this way can we achieve the transition from traditional spontaneous fermentation to modern inoculated fermentation.


Subject(s)
Fermentation , Vegetables , Bacteria , Fermented Foods/microbiology , Food Microbiology/methods , Microbiota , Vegetables/microbiology , Yeasts
7.
Viruses ; 16(5)2024 05 14.
Article in English | MEDLINE | ID: mdl-38793656

ABSTRACT

Human norovirus (HuNoV) is a leading global cause of viral gastroenteritis, contributing to numerous outbreaks and illnesses annually. However, conventional cell culture systems cannot support the cultivation of infectious HuNoV, making its detection and study in food and water matrices particularly challenging. Recent advancements in HuNoV research, including the emergence of models such as human intestinal enteroids (HIEs) and zebrafish larvae/embryo, have significantly enhanced our understanding of HuNoV pathogenesis. This review provides an overview of current methods employed for HuNoV detection in food and water, along with their associated limitations. Furthermore, it explores the potential applications of the HIE and zebrafish larvae/embryo models in detecting infectious HuNoV within food and water matrices. Finally, this review also highlights the need for further optimization and exploration of these models and detection methods to improve our understanding of HuNoV and its presence in different matrices, ultimately contributing to improved intervention strategies and public health outcomes.


Subject(s)
Caliciviridae Infections , Gastroenteritis , Norovirus , Zebrafish , Animals , Humans , Caliciviridae Infections/virology , Caliciviridae Infections/diagnosis , Food Microbiology/methods , Gastroenteritis/virology , Norovirus/isolation & purification , Norovirus/genetics , Water Microbiology , Zebrafish/virology , Disease Models, Animal
8.
Anal Methods ; 16(22): 3448-3463, 2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38804827

ABSTRACT

Some physical phenomena and various chemical substances newly introduced in nanotechnology have allowed scientists to develop valuable devices in the field of food sciences. Regarding such progress, the identification of foodborne pathogenic microorganisms is an imperative subject nowadays. These bacterial species have been found to cause severe health impacts after food ingestion and can result in high mortality in acute cases. The rapid detection of foodborne bacterial species at low concentrations is in high demand in recent diagnostics. CRISPR/Cas-mediated biosensors possess the potential to overcome several challenges in classical assays such as complex pretreatments, long turnaround time, and insensitivity. Among them, colorimetric nanoprobes based on the CRISPR strategy afford promising devices for POCT (point-of-care testing) since they can be visualized with the naked eye and do not require diagnostic apparatus. In this study, we briefly classify and discuss the working principles of the different CRISPR/Cas protein agents that have been employed in biosensors so far. We assess the current status of the CRISPR system, specifically focusing on colorimetric biosensing platforms. We discuss the utilization of each Cas effector in the detection of foodborne pathogens and examine the restrictions of the existing technology. The challenges and future opportunities are also indicated and addressed.


Subject(s)
Biosensing Techniques , CRISPR-Cas Systems , Colorimetry , Food Microbiology , Foodborne Diseases , Biosensing Techniques/methods , Colorimetry/methods , Food Microbiology/methods , Foodborne Diseases/microbiology , Foodborne Diseases/diagnosis , Humans , Bacteria/isolation & purification , Bacteria/genetics
9.
Sensors (Basel) ; 24(8)2024 Apr 19.
Article in English | MEDLINE | ID: mdl-38676242

ABSTRACT

Foodborne pathogens are microbes present in food that cause serious illness when the contaminated food is consumed. Among these pathogens, Listeria monocytogenes is one of the most serious bacterial pathogens, and causes severe illness. The techniques currently used for L. monocytogenes detection are based on common molecular biology tools that are not easy to implement for field use in food production and distribution facilities. This work focuses on the efficacy of an electrochemical biosensor in detecting L. monocytogenes in chicken broth. The sensor is based on a nanostructured electrode modified with a bacteriophage as a bioreceptor which selectively detects L. monocytogenes using electrochemical impedance spectroscopy. The biosensing platform was able to reach a limit of detection of 55 CFU/mL in 1× PBS buffer and 10 CFU/mL in 1% diluted chicken broth. The biosensor demonstrated 83-98% recovery rates in buffer and 87-96% in chicken broth.


Subject(s)
Biosensing Techniques , Chickens , Dielectric Spectroscopy , Food Microbiology , Listeria monocytogenes , Listeria monocytogenes/isolation & purification , Biosensing Techniques/methods , Animals , Food Microbiology/methods , Electrodes
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 315: 124261, 2024 Jul 05.
Article in English | MEDLINE | ID: mdl-38608560

ABSTRACT

Food safety is always of paramount importance globally due to the devasting social and economic effects of foodborne disease outbreaks. There is a high consumption rate of meat worldwide, making it an essential protein source in the human diet, hence its microbial safety is of great importance. The food industry stakeholders are always in search of methods that ensure safe food whilst maintaining food quality and excellent sensory attributes. Currently, there are several methods used in microbial food analysis, however, these methods are often time-consuming and do not allow real-time analysis. Considering the recent technological breakthroughs in artificial intelligence and machine learning, it raises the question of whether these advancements could be leveraged within the meat industry to improve turnaround time for microbial assessments. Hyperspectral imaging (HSI) is a highly prospective technology worth exploring for microbial analysis. The rapid, non-destructive method has the potential to be integrated into food production systems and allows foodborne pathogen detection in food samples, thus saving time. Although there has been a substantial increase in research on the utilisation of HSI in food applications over the past years, its use in the microbial assessment of meat is not yet optimal. This review aims to provide a basic understanding of the visible-near infrared HSI system, recent applications in the microbial assessment of meat products, challenges, and possible future applications.


Subject(s)
Food Microbiology , Hyperspectral Imaging , Meat , Hyperspectral Imaging/methods , Meat/analysis , Meat/microbiology , Food Microbiology/methods , Animals , Bacteria/isolation & purification , Humans , Spectroscopy, Near-Infrared/methods
11.
Braz J Microbiol ; 55(2): 1723-1733, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38639846

ABSTRACT

Shiga toxigenic E. coli are important foodborne zoonotic pathogens. The present study was envisaged to standardize loop-mediated isothermal amplification assays targeting stx1 and stx2 genes for rapid and visual detection of STEC and compare its sensitivity with PCR. The study also assessed the effect of short enrichment on the detection limit of LAMP and PCR. The developed LAMP assays were found to be highly specific. Analytical sensitivity of LAMP was 94 fg/µLand 25.8 fg/µL for stx-1 and stx-2 while LOD of 5 CFU/g of carabeef was measured after 6-12 h enrichment. The study highlights the importance of short (6-12 h) enrichment for improving the sensitivity of LAMP. The entire detection protocol could be performed within 9 h yielding results on the same day. The developed LAMP assays proved to be a handy and cost-effective alternative for screening STEC contamination in meat.


Subject(s)
Meat , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Sensitivity and Specificity , Shiga-Toxigenic Escherichia coli , Shiga-Toxigenic Escherichia coli/genetics , Shiga-Toxigenic Escherichia coli/isolation & purification , Nucleic Acid Amplification Techniques/methods , Animals , Molecular Diagnostic Techniques/methods , Meat/microbiology , Food Microbiology/methods , Shiga Toxin 1/genetics , Shiga Toxin 2/genetics , Food Contamination/analysis
12.
Anal Bioanal Chem ; 416(15): 3509-3518, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38647692

ABSTRACT

Escherichia coli O157:H7 (E. coli O157:H7) is a foodborne pathogenic microorganism that is commonly found in the environment and poses a significant threat to human health, public safety, and economic stability worldwide. Thus, early detection is essential for E. coli O157:H7 control. In recent years, a series of E. coli O157:H7 detection methods have been developed, but the sensitivity and portability of the methods still need improvement. Therefore, in this study, a rapid and efficient testing platform based on the CRISPR/Cas12a cleavage reaction was constructed. Through the integration of recombinant polymerase amplification and lateral flow chromatography, we established a dual-interpretation-mode detection platform based on CRISPR/Cas12a-derived fluorescence and lateral flow chromatography for the detection of E. coli O157:H7. For the fluorescence detection method, the limits of detection (LODs) of genomic DNA and E. coli O157:H7 were 1.8 fg/µL and 2.4 CFU/mL, respectively, within 40 min. Conversely, for the lateral flow detection method, LODs of 1.8 fg/µL and 2.4 × 102 CFU/mL were achieved for genomic DNA and E. coli O157:H7, respectively, within 45 min. This detection strategy offered higher sensitivity and lower equipment requirements than industry standards. In conclusion, the established platform showed excellent specificity and strong universality. Modifying the target gene and its primers can broaden the platform's applicability to detect various other foodborne pathogens.


Subject(s)
CRISPR-Cas Systems , Escherichia coli O157 , Limit of Detection , Escherichia coli O157/genetics , Escherichia coli O157/isolation & purification , DNA, Bacterial/analysis , DNA, Bacterial/genetics , Food Microbiology/methods , CRISPR-Associated Proteins/genetics , Humans , Endodeoxyribonucleases/genetics
13.
Braz J Microbiol ; 55(2): 1783-1791, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38687417

ABSTRACT

The aim of the present study was to compare the performance of a nested polymerase chain reaction (nPCR) and a real-time PCR based on the amplification of the HlyA gene from Listeria monocytogenes using a plasmid DNA standard. Nested PCR was developed with an internal amplification control (IAC). Both techniques were validated in soft cheese samples by comparing their results with the results of the microbiological reference method ISO 11290-1:2017. Cheese samples artificially contaminated with 3.5 to 3,500 UFC/25 g were processed by ISO 11290-1:2017 and, at several times of culture, DNA samples were extracted. All cheeses contaminated with L. monocytogenes were positive for the microbiological method 96 h post contamination and for nPCR and real-time PCR 48 h post contamination. At this time, the HlyA gene was amplified in all contaminated samples. Both molecular techniques showed the same sensitivity, 30 copies/reaction or 3.5 UFC/25 g, when plasmid DNA standard or artificially contaminated cheese samples were used. Finally, eighty soft cheese samples obtained from local retail stores and tested by three methods were negative, indicating a 100% concordance in results. The development of an nPCR with IAC reinforces the reliability of the negative results without increasing the costs of the reaction. Besides, nPCR showed less sensitivity to the presence of inhibitory substances in the reaction. The use of one of these molecular techniques could be easily coupled to the microbiological method, serving as a screening method in the food industry for hygiene monitoring and early identification of contaminated foods.


Subject(s)
Cheese , Food Microbiology , Listeria monocytogenes , Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction , Cheese/microbiology , Listeria monocytogenes/genetics , Listeria monocytogenes/isolation & purification , Real-Time Polymerase Chain Reaction/methods , Polymerase Chain Reaction/methods , Food Microbiology/methods , Hemolysin Proteins/genetics , Bacterial Toxins/genetics , DNA, Bacterial/genetics , Heat-Shock Proteins
14.
J Food Sci ; 89(5): 3006-3018, 2024 May.
Article in English | MEDLINE | ID: mdl-38532705

ABSTRACT

Wine faults threaten brand recognition and consumer brand loyalty. The objective of this study was to compare the acuteness of e-tongue and human sensory evaluation of wine fault development in Riesling wine over 42 days of storage. Riesling wines uninoculated (control) or inoculated with 104 CFU/mL cultures of Wickerhamomyces anomalus, Acetobacter aceti, Lactobacillus brevis, or Pediococcus parvulus were assessed every 7 days with the e-tongue and a rate-all-that-apply (RATA) sensory panel. After 7 days of storage, the e-tongue detected differences in all four wine spoilage microorganism treatments, compared to control wine, with discrimination indices over 86%. The RATA sensory panel detected significant differences beginning on day 35 of storage, 28 days after the e-tongue detected differences. This study showed that the e-tongue was more sensitive than the human panel as a detection tool, without sensory fatigue. PRACTICAL APPLICATION: This research is useful for winemakers seeking additional instrumental methods in the early detection of wine faults. Given the results of this study, the e-tongue can be a useful tool for detecting early chemical changes in white wines that have undergone microbial spoilage, providing winemakers with time to mitigate faults before they surpass sensory thresholds.


Subject(s)
Taste , Wine , Wine/analysis , Wine/microbiology , Humans , Electronic Nose , Odorants/analysis , Adult , Food Microbiology/methods , Female , Male , Food Storage/methods
15.
Foodborne Pathog Dis ; 21(5): 298-305, 2024 May.
Article in English | MEDLINE | ID: mdl-38484326

ABSTRACT

Salmonella spp. is among the most central etiological agents in foodborne bacterial disorders. To identify Salmonella spp., numerous new molecular techniques have been developed conversely to the traditional culture-based methods. In this work, a new peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) method was developed for the specific detection of Salmonella species, allowing a faster analysis compared with the traditional methods (ISO 6579-1: 2017). The method was optimized based on a novel PNA probe (SalPNA1692) combined with a blocker probe to detect Salmonella in food samples through an assessment of diverse-rich and selective enrichment broths. Our findings indicated that the best outcome was obtained using a 24-h pre-enrichment step in buffered peptone water, followed by RambaQuick broth selective enrichment for 16 h. For the enrichment step performance validation, fresh ground beef was artificially contaminated with two ranges of concentration of inoculum: a low level (0.2-2 colony-forming units [CFUs]/25 g) and a high level (2-10 CFUs/25 g). The new PNA-FISH method presented a specificity of 100% and a detection limit of 0.5 CFU/25 g of food sample, which confirms the great potential of applying PNA probes in food analysis.


Subject(s)
Food Microbiology , In Situ Hybridization, Fluorescence , Peptide Nucleic Acids , Salmonella , In Situ Hybridization, Fluorescence/methods , Salmonella/isolation & purification , Salmonella/genetics , Food Microbiology/methods , Animals , Food Contamination/analysis , Cattle , Sensitivity and Specificity , Limit of Detection , Red Meat/microbiology
16.
Adv Sci (Weinh) ; 11(21): e2309753, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38544489

ABSTRACT

Maintaining precise temperature control is vital for cold chain food transport, as temperature fluctuations can cause significant food safety and quality issues. During transport, ice that melts can promote the growth of microbes and their spread, resulting in microbial cross-contamination. This study developed sustainable, non-melting, self-sanitizing "ice cubes" using food grade compositions including microporous cellulose sponges (MCS) and photosensitizers, aimed at enhancing temperature regulation and minimizing microbial contamination in the cold chain. Upon absorbing water, the MCS matched traditional ice in cooling efficiency and heat absorption and exhibit remarkable mechanical and thermal durability, withstanding multiple freeze-thaw cycles and compressive stresses. The cationic MCS combined with erythrosine B demonstrated strong self-sanitizing capabilities, effectively reducing microbial cross-contamination in food models. Additionally, the release rates of photosensitizers from the MCS can be modulated by altering environmental ionic strength. This research offers viable solutions to address microbial cross-contamination challenges in current cold chain systems.


Subject(s)
Cellulose , Food Microbiology/methods , Porosity , Food Contamination/prevention & control , Cold Temperature
17.
J AOAC Int ; 107(3): 471-478, 2024 May 02.
Article in English | MEDLINE | ID: mdl-38407384

ABSTRACT

BACKGROUND: For pathogen detection in food, there are occasions where samples cannot be processed immediately after selective enrichment or need to be reexamined days or weeks later for confirmation or retest. OBJECTIVE: This study aimed to investigate the effect of different prolonged period of storage of selective enrichments of food at 4 ± 2°C and room temperature (20-22°C) on the detection and isolation of Salmonella. METHOD: This study included two experiments involving 34 types of foods to compare the effect of 4 ± 2°C and room temperature storage on the detection of Salmonella in 204 selective enrichments (Rappaport-Vassiliadis [RV] and Tetrathionate [TT] broths) during a 42-day storage (Experiment I); and to monitor the survival of Salmonella in 300 selective enrichments (RV and TT) with different pre-enrichment broths (Lactose broth [LB] or Buffered peptone water broth [BPW]), stored at 4°C for 60 days (Experiment II). All the samples were subjected to Salmonella analysis following the FDA BAM method. RESULTS: During multiple samplings, the positive detection rate for Salmonella remained consistent through Day 42 after selective enrichment, irrespective of Salmonella serotype, storage temperature, pre-enrichment broth, or selective enrichment broth in both Experiment I and II. However, on Day 60 sampling in Experiment II, seven previously positive results turned to negatives. These data indicated that storage of RV and TT enrichments at 4 ± 2°C or room temperature for up to 42 days after selective enrichment did not compromise the detection of Salmonella in the tested food categories, regardless of Salmonella serotypes and the broths used for pre-enrichment and selective enrichment. CONCLUSIONS: At least for the food types studied in this experiment, the recovery of Salmonella from selective enrichments could be postponed for a limited period of time (e.g., <42 days) if needed without adversely affecting the test results. However, the delayed analysis of TT and RV enrichments does pose a risk of reduced detection sensitivity, as evidenced by the seven negative results on Day 60 compared to previous positives. We do not recommend or endorse delaying the analysis of TT and RV enrichments. HIGHLIGHTS: In the food matrixes investigated in this experiment, the plating and isolation of Salmonella from selective TT and RV enrichments stored at 4 ± 2°C or room temperature could be deferred for a period (up to 42 days) without any negative effect on the test results, if necessary.


Subject(s)
Food Microbiology , Salmonella , Temperature , Salmonella/isolation & purification , Food Microbiology/methods , Time Factors , Food Storage , Food Contamination/analysis , Culture Media
18.
Adv Biochem Eng Biotechnol ; 187: 339-380, 2024.
Article in English | MEDLINE | ID: mdl-38409265

ABSTRACT

The contamination of food by bacterial pathogens represents a substantial hazard for human and animal health. Therefore, considerable effort is focused on the development of effective methods for monitoring food safety. A current trend in this field is the development of biosensors that can be used in remote food laboratories and even in farms to check food contamination prior to its delivery to consumers or its further processing in the food industry. Among receptors that can recognize proteins or lipopolysaccharides (LPS) on bacterial surfaces, aptamers play an important role. An aptamer consists of a single strand of DNA or RNA that folds into a 3D structure when placed in a solution, forming a binding site for the target. This chapter presents an overview of recent achievements in bacterial pathogen detection through the development of electrochemical, optical, and acoustic biosensors based on DNA aptamers. Thus far, these biosensors exhibit good sensitivity and selectivity, comparable with conventional methods currently used in food laboratories. However, these biosensors offer several advantages over conventional methods: they are of low cost, easier to handle, and respond more quickly. Biosensor technology is therefore an important tool for monitoring food safety.


Subject(s)
Aptamers, Nucleotide , Bacteria , Biosensing Techniques , Biosensing Techniques/methods , Aptamers, Nucleotide/chemistry , Bacteria/genetics , Bacteria/isolation & purification , Food Microbiology/methods , Food Microbiology/trends , Humans , Food Contamination/analysis , Food Safety/methods
19.
Nat Protoc ; 19(5): 1291-1310, 2024 May.
Article in English | MEDLINE | ID: mdl-38267717

ABSTRACT

Deep investigation of the microbiome of food-production and food-processing environments through whole-metagenome sequencing (WMS) can provide detailed information on the taxonomic composition and functional potential of the microbial communities that inhabit them, with huge potential benefits for environmental monitoring programs. However, certain technical challenges jeopardize the application of WMS technologies with this aim, with the most relevant one being the recovery of a sufficient amount of DNA from the frequently low-biomass samples collected from the equipment, tools and surfaces of food-processing plants. Here, we present the first complete workflow, with optimized DNA-purification methodology, to obtain high-quality WMS sequencing results from samples taken from food-production and food-processing environments and reconstruct metagenome assembled genomes (MAGs). The protocol can yield DNA loads >10 ng in >98% of samples and >500 ng in 57.1% of samples and allows the collection of, on average, 12.2 MAGs per sample (with up to 62 MAGs in a single sample) in ~1 week, including both laboratory and computational work. This markedly improves on results previously obtained in studies performing WMS of processing environments and using other protocols not specifically developed to sequence these types of sample, in which <2 MAGs per sample were obtained. The full protocol has been developed and applied in the framework of the European Union project MASTER (Microbiome applications for sustainable food systems through technologies and enterprise) in 114 food-processing facilities from different production sectors.


Subject(s)
Microbiota , Microbiota/genetics , Food Handling/methods , DNA, Bacterial/genetics , DNA, Bacterial/isolation & purification , Metagenome , Metagenomics/methods , DNA/isolation & purification , Sequence Analysis, DNA/methods , Food Microbiology/methods
20.
Food Res Int ; 174(Pt 2): 113665, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37981373

ABSTRACT

As outbreaks of foodborne illness caused by the opportunistic pathogen Cronobacter sakazakii (Cs) continue to occur, particularly in infants consuming powdered infant formula (PIF), the need for sensitive, rapid, and easy-to-use detection of Cs from food and food processing environments is increasing. Here, we developed bioluminescent reporter bacteriophages for viable Cs-specific, substrate-free, rapid detection by introducing luciferase and its corresponding substrate-providing enzyme complex into the virulent phage ΦC01. Although the reporter phage ΦC01_lux, constructed by replacing non-essential genes for phage infectivity with a luxCDABE reporter operon, produced bioluminescence upon Cs infection, the emitted signal was quickly decayed due to the superior bacteriolytic activity of ΦC01. By truncating the membrane pore-forming protein holin and thus limiting its function, the bacterial lysis was delayed and the resultant engineered reporter phage ΦC01_lux_Δhol could produce a more stable and reliable bioluminescent signal. Accordingly, ΦC01_lux_Δhol was able to detect at least an average of 2 CFU/ml of Cs artificially contaminated PIF and Sunsik and food contact surface models within a total of 7 h of assays, including 5 h of pre-enrichment for Cs amplification. The sensitive, easy-to-use, and specific detection of live Cs with the developed reporter phage could be applied as a novel complementary tool for monitoring Cs in food and food-related environments for food safety and public health.


Subject(s)
Bacteriological Techniques , Bacteriophages , Cronobacter sakazakii , Food Microbiology , Luminescent Measurements , Viral Proteins , Cronobacter sakazakii/genetics , Cronobacter sakazakii/isolation & purification , Bacteriological Techniques/methods , Bacteriophages/genetics , Bacteriophages/metabolism , Viral Proteins/genetics , Viral Proteins/metabolism , Food Microbiology/methods , Genome, Viral/genetics , Sequence Deletion , Luminescent Measurements/methods , Sensitivity and Specificity
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