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Understanding biofilm rheology is crucial for industrial and domestic food safety practices. This comprehensive review addresses the knowledge gap on the rheology of biofilm. Specifically, the review explores the influence of fluid flow, shear stress, and substrate properties on the initiation, structure, and functionality of biofilms, as essential implications for food safety. The viscosity and shear‐thinning characteristics of non‐Newtonian fluids may impact the attachment and detachment dynamics of biofilms, influencing their stability and resilience under different flow conditions. The discussion spans multiple facets, including the role of extracellular polymeric substances (EPSs) in biofilm formation, the impact of rheological attributes of biofilm on their adhesion to surfaces, and the influence of shear forces between biofilms and substrate's surface characteristics on biofilm stability. Analytical techniques, encompassing rheometry, microscopy, and molecular biology approaches, are scrutinized for their contributions to understanding these interactions. The paper delves into the implications for the food industry, highlighting potential risks associated with biofilm formation and proposing strategies for effective control and prevention. Future research directions and the integration of rheological considerations into food safety regulations are underscored as pivotal steps in mitigating biofilm‐related risks. The synthesis of microbiology, materials science, and engineering perspectives offers a multidimensional exploration of rheology–biofilm interactions, laying the groundwork for informed interventions in diverse industrial settings. [ABSTRACT FROM AUTHOR]

In recent years, plant essential oils have been confirmed as natural inhibitors of foodborne pathogens. Citrus reticulata Blanco cv. Tankan peel essential oil (CPEO) showed anti-Listeria monocytogenes (LM) activities, and this study investigated the associated mechanisms by using high-resolution electron microscope, fluorescence spectrometer, flow cytometer, potentiometer, and transcriptome sequencing. The results showed that CPEO restrained LM growth at a minimum inhibitory concentration of 2% (v/v). The anti-LM abilities of CPEO were achieved by disrupting the permeability of the cell wall, damaging the permeability, fluidity, and integrity of the cell membrane, disturbing the membrane hydrophobic core, and destroying the membrane protein conformation. Moreover, CPEO could significantly inhibit the LM aggregation from forming biofilm by reducing the extracellular polymeric substances' (protein, polysaccharide, and eDNA) production and bacterial surface charge numbers. The RNA sequencing data indicated that LM genes involved in cell wall and membrane biosynthesis, DNA replication and repair, quorum sensing and two-component systems were expressed differently after CPEO treatment. These results suggested that CPEO could be used as a novel anti-LM agent and green preservative in the food sector. Further studies are needed to verify the anti-LM activities of CPEO in real food. [ABSTRACT FROM AUTHOR]

Understanding factors influencing Listeria monocytogenes biofilms aid in developing more effective elimination/prevention strategies. This study examined the effect of temperature (4 °C, 21 °C, 30 °C), materials (stainless steel 316 L with 2B and 2 R finishes, glass, and polypropylene), and slope (0°/horizontal or 90°/vertical) on mono- and dual-species biofilms using two L. monocytogenes strains and one Pseudomonas aeruginosa strain. All biofilms were grown in 10% TSB for 24 h and analyzed using culture-based methods. Additionally, the architecture of monospecies biofilms was studied using fluorescence microscopy. Overall, P. aeruginosa showed higher biofilm formation potential (6.2 log CFU/cm2) than L. monocytogenes (4.0 log CFU/cm2). Temperature greatly influenced P. aeruginosa and varied for L. monocytogenes. The slope predominantly influenced L. monocytogenes monospecies biofilms, with cell counts increasing by up to 2 log CFU/cm2. Surface material had little impact on biofilm formation. The study highlights the varying effects of different parameters on multispecies biofilms and the importance of surface geometry. HIGHLIGHTS: Surface material does not affect L. monocytogenes or P. aeruginosa biofilms L. monocytogenes produces more biofilm on horizontal surfaces than on vertical surfaces In dual-species biofilm, L. monocytogenes shows enhanced biofilm production Increased temperature often results in enhanced biofilm formation [ABSTRACT FROM AUTHOR]

Biofilms are the natural state for bacterial and fungal species. To achieve surface hygiene in commercial facilities, the presence of biofilms must be adequately considered. However, standard disinfectant and sanitizer efficacy tests required by the US-EPA and the European Committee for Standardization (CEN) do not currently consider the role of environmental biofilms. This selective review will discuss what biofilms are and why they are important. We will also cover where they are commonly found in healthcare and food processing facilities and explore how current antimicrobial test methods required for product registration do not test for the presence of biofilms. Additionally, we will explore how a lack of efficacy against biofilms may play a role in the development of antimicrobial resistance in healthcare facilities due to the exchange of mobile genetic elements that occur readily in a biofilm matrix. [ABSTRACT FROM AUTHOR]

Listeriosis, an invasive illness with a fatality rate between 20% and 30%, is caused by the ubiquitous bacterium Listeria monocytogenes. Human listeriosis has long been associated with foods. This is because the ubiquitous nature of the bacteria renders it a common food contaminant, posing a significant risk to the food processing sector. Although several sophisticated stress coping mechanisms have been identified as significant contributing factors toward the pathogen's persistence, a complete understanding of the mechanisms underlying persistence across various strains remains limited. Moreover, aside from genetic aspects that promote the ability to cope with stress, various environmental factors that exist in food manufacturing plants could also contribute to the persistence of the pathogen. The objective of this review is to provide insight into the challenges faced by the dairy industry because of the pathogens' environmental persistence. Additionally, it also aims to emphasize the diverse adaptation and response mechanisms utilized by L. monocytogenes in food manufacturing plants to evade environmental stressors. The persistence of L. monocytogenes in the food processing environment poses a serious threat to food safety and public health. The emergence of areas with high levels of L. monocytogenes contamination could facilitate Listeria transmission through aerosols, potentially leading to the recontamination of food, particularly from floors and drains, when sanitation is implemented alongside product manufacturing. Hence, to produce safe dairy products and reduce the frequency of outbreaks of listeriosis, it is crucial to understand the factors that contribute to the persistence of this pathogen and to implement efficient control strategies. [ABSTRACT FROM AUTHOR]

In 2023, Listeria monocytogenes persistence remains a problem in the food business. A profound understanding of how this pathogen persists may lead to better aimed intervention/prevention strategies. The lack of a uniform definition of persistence makes the comparison between studies complex. Harborage sites offer protection against adverse environmental conditions and form the ideal habitat for the formation of biofilms, one of the major persistence strategies. A retarded growth rate, disinfectant resistance/tolerance, desiccation resistance/tolerance, and protozoan protection complete the list of persistence strategies for Listeria monocytogenes and can occur on themselves or in combination with biofilms. Based on the discussed persistence strategies, intervention strategies are proposed. By enhancing the focus on four precaution principles (cleaning and disinfection, infrastructure/hygienic design, technical maintenance, and work methodology) as mentioned in Regulation (EC) No. 852/2004, the risk of persistence can be decreased. All of the intervention strategies result in obtaining and maintaining a good general hygiene status throughout the establishment at all levels ranging from separate equipment to the entire building. [ABSTRACT FROM AUTHOR]

Among bacterial foodborne pathogens, Listeria monocytogenes represents one of the most important public health concerns in seafood industries. This study was designed as a retrospective study which aimed to investigate the trend of antibiotic resistance genes (ARGs) circulation in L. monocytogenes isolates identified (in the last 15 years) from Atlantic salmon (Salmo salar) fresh and smoked fillets and environmental samples. For these purposes, biomolecular assays were performed on 120 L. monocytogenes strains collected in certain years and compared to the contemporary scientific literature. A total of 52.50% (95% CI: 43.57–61.43%) of these samples were resistant to at least one antibiotic class, and 20.83% (95% CI: 13.57–28.09%) were classified as multidrug resistant. Concerning ARGs circulation, tetracycline (tetC, tetD, tetK, tetL, tetS), aminoglycoside (aadA, strA, aacC2, aphA1, aphA2), macrolide (cmlA1, catI, catII), and oxazolidinone (cfr, optrA, poxtA) gene determinants were majorly amplified. This study highlights the consistent ARGs circulation from fresh and processed finfish products and environmental samples, discovering resistance to the so-called critical important antimicrobials (CIA) since 2007. The obtained ARGs circulation data highlight the consistent increase in their diffusion when compared to similar contemporary investigations. This scenario emerges as the result of decades of improper antimicrobial administration in human and veterinary medicine. [ABSTRACT FROM AUTHOR]

In recent years, due to the globalization of food trade and certified agro-food products, the authenticity and traceability of food have received increasing attention. As a result, opportunities for fraudulent practices arise, highlighting the need to protect consumers from economic and health damages. In this regard, specific analytical techniques have been optimized and implemented to support the integrity of the food chain, such as those targeting different isotopes and their ratios. This review article explores the scientific progress of the last decade in the study of the isotopic identity card of food of animal origin, provides the reader with an overview of its application, and focuses on whether the combination of isotopes with other markers increases confidence and robustness in food authenticity testing. To this purpose, a total of 135 studies analyzing fish and seafood, meat, eggs, milk, and dairy products, and aiming to examine the relation between isotopic ratios and the geographical provenance, feeding regime, production method, and seasonality were reviewed. Current trends and major research achievements in the field were discussed and commented on in detail, pointing out advantages and drawbacks typically associated with this analytical approach and arguing future improvements and changes that need to be made to recognize it as a standard and validated method for fraud mitigation and safety control in the sector of food of animal origin. [ABSTRACT FROM AUTHOR]

Food contact surfaces (FCSs) include all surfaces that may come in contact with the food during production, processing, and packaging. Food processing industries encounter several challenges due to its microbial interaction with the FCSs, such as cross contamination of pathogenic microorganism or allergens in food, formation of biofilm, biodeterioration of food contact surface leads to food with reduced shelf-life and quality. A legal EU framework provides the fundamental postulates for the safety and inertness for all Food Contact Materials (FCMs). Legislations have an important role in providing regulatory guidance on the quality assurance systems and verifying their implementation as a means of regulatory compliance. This review article is focused on the challenges faced by the food processing industry with respect to food contact surfaces. Furthermore, relevant regulations provided by the European framework regarding the food contact materials are also discussed. Finally, new approaches which stand as the solutions to these challenges are discussed. [ABSTRACT FROM AUTHOR]

Low-salt meat (salt content <2%) is gaining popularity for its lower health risks, while the food industry faces technical challenges in improving its quality. Twenty-one studies involving meat quality improvement measures in low-salt meat products were included in this meta-analysis. The outcomes of these studies were assessed to derive conclusions about their effects on meat hardness and cooking losses. The results demonstrated that higher power ultrasound treatments (300–1500 W) significantly increased the hardness of low-salt meat, while a similar outcome was also achieved by low-strength (50–200 MPa) high-pressure processing (HPP) treatment, which was beneficial for alleviating the undesirable too-soft texture of the low-salt meat products. Furthermore, when salt reduction was greater than 50%, the application of ultrasonic treatment and HPP of 50–200 MPa significantly reduced the cooking losses, and the addition of hydrocolloids also increased the cooking yield of the salt-reduced meat products. Among all the interventions, HPP exhibited the most significant effects in low-salt meat quality improvement, which warrants future studies on the combination of this method with salt reduction strategies in the reduction of salt content in processed meat products. [ABSTRACT FROM AUTHOR]

Introduction: informal food marketing is predominantly practiced in developing countries as it solves major social and economic challenges through the provision of employment and easily accessible food products at relatively inexpensive prices. However, such products often escape effective health and safety regulations which relatively characterize formal marketing, thus posing threats to public health. Methods: we conducted a cross-sectional microbial assessment of randomly collected raw meats (n=224) sold at selected informal (n=112) and formal (n=112) meat markets in Ibadan, south-western Nigeria for Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and Salmonella spp. using standard protocols. Isolates were evaluated for antibiogram patterns by Kirby-Bauer Assay and data analysed using descriptive statistics and logistic regression. Results: overall, 75.5%, 65.2%, 61.6%, and 46.9% of the 224 samples were positive for S. aureus, L. monocytogenes, Salmonella spp, and E. coli, respectively. Significantly higher prevalences were obtained from the informal markets for S. aureus (OR=9.43; 95%CI: 0.05-0.24), L. monocytogenes (OR=9.35; 95%CI: 0.06-0.21), Salmonella spp (OR=10.00; 95%CI: 0.05-0.19) and E. coli (OR=12.99; 95%CI: 0.04-0.15) than the formal markets. The pathogens exhibited total resistance against half of the 14 antibiotics studied, with the least resistance to ciprofloxacin and ofloxacin. Conclusion: the significantly higher microbial contamination in meats from informal markets and associated high antibiotic resistance level portends serious public health implications of informal meat marketing. Since informal food marketing also characterizes other developing sub-Saharan African countries, synergy among local and international stakeholders to step up health and safety policies towards regulating activities at informal food markets is urgently required. [ABSTRACT FROM AUTHOR]

Similar to Escherichia coli O157, non‐O157 also inherits certain acid resistance, and its stress response can be induced under acidic conditions, which may be affected by temperature. In this study, O26, the main serotype of non‐O157 E. coli, was investigated in order to evaluate the effect of lactic acid stress on its biofilm formation (BF) at different temperatures. Firstly, the BF ability of 22 isolates of E. coli O26 were compared by means of crystal violet staining and the result showed that all strains had certain BF ability with variation among strains. Then, the strain 126Z with strong capacity and strain G13Z2 with medium capacity were selected for BF experiment in acidic TSB (pH 4.0 and 5.0, adjusted with lactic acid) at 15°C and 25°C, respectively. The results showed that the BF of O26 was decreased with increasing concentration of lactic acid, and the higher the concentration of lactic acid was, the less the amount of biofilm formed. Moreover, the effect of temperature on BF of different capacity strains was related to the pH value, that is, with a lower concentration of lactic acid, the higher the temperature was, the faster the biofilm amount increased. Under a higher acid concentration, the BF of two strains showed different dynamic changes and were inhibited in the later stage, in which the biofilm amount of 126Z decreased significantly at 15°C, while that of G13Z2 decreased more significant at 25°C. This observation was further confirmed by scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM). This finding suggests that combined temperature and lactic acid intervention may be an effective method to prevent BF, and the results of present work would provide scientific basis for the risk assessment of E. coli O26 in food processing. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is widely present in biotic and abiotic surfaces, including manure, soil, and surface water samples. It is an environmentally persistent organism and can grow slowly even at refrigeration temperatures (4°C) in a variety of food products. This foodborne pathogen can attach firmly and form biofilms on any food-contact and nonfood contact surface in almost all food processing conditions. It is still unclear what factors play a critical role in the food production facility in biofilm formation of L. monocytogenes. This review explores the known factors inducing the L. monocytogenes biofilm formation ability on food-contact and non-food contact surfaces and their elimination by disinfectant procedures in the food processing facilities. [ABSTRACT FROM AUTHOR]

Starter cultures are defined as selected microbial preparations used to increase the efficiency of fermentation processes. In the food industry, numerous microbial cultures are used to ensure the production of safe and high-quality commodities. This review provides a comprehensive theoretical guide for selecting microbial cultures for use in the manufacturing of industrially important food commodities, including dairy, meat, vegetables, alcoholic beverages, cocoa, coffee, vinegar, and soy-based products. Related topics on fermented food classification, microbial domestication, and regulatory requirements are addressed. The strategies reported in this review are useful to help researchers choose methods and criteria selection. [ABSTRACT FROM AUTHOR]

Concerns about food contamination by Listeria monocytogenes are on the rise with increasing consumption of ready-to-eat foods. Biofilm production of L. monocytogenes is presumed to be one of the ways that confer its increased resistance and persistence in the food chain. In this study, a collection of isolates from foods and food processing environments (FPEs) representing persistent, prevalent, and rarely detected genotypes was evaluated for biofilm forming capacities including adhesion and sessile biomass production under diverse environmental conditions. The quantity of sessile biomass varied according to growth conditions, lineage, serotype as well as genotype but association of clonal complex (CC) 26 genotype with biofilm production was evidenced under cold temperature. In general, relative biofilm productivity of each strain varied inconsistently across growth conditions. Under our experimental conditions, there were no clear associations between biofilm formation efficiency and persistent or prevalent genotypes. Distinct extrinsic factors affected specific steps of biofilm formation. Sudden nutrient deprivation enhanced cellular adhesion while a prolonged nutrient deficiency impeded biofilm maturation. Salt addition increased biofilm production, moreover, nutrient limitation supplemented by salt significantly stimulated biofilm formation. Pan-genome-wide association study (Pan-GWAS) assessed genetic composition with regard to biofilm phenotypes for the first time. The number of reported genes differed depending on the growth conditions and the number of common genes was low. However, a broad overview of the ontology contents revealed similar patterns regardless of the conditions. Functional analysis showed that functions related to transformation/competence and surface proteins including Internalins were highly enriched. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes has a significant impact on the food industry by forming biofilms on food‐processing equipment. Tandem analysis of whole‐genome sequencing data with biofilm data from 166 environmental and food‐related L. monocytogenes isolates has revealed serotypic and genetic factors that strongly correlate with adherence and biofilm formation, such as lineage, plasmid harbourage, a three‐codon deletion in inlA and the presence of the stress survival islet 1 (SSI‐1). Strains from serotype 1/2b, the majority of which contained SSI‐1, formed the strongest biofilms, while serotype 4b strains, the majority of which did not contain SSI‐1, formed the weakest biofilms. When serotype 1/2a was separated by its SSI‐1 genotype, SSI‐1‐positive 1/2a strains demonstrated significantly higher capacity for biofilm formation after 3 days of growth at 30°C (P < 0·0001). Together, these findings indicate that SSI‐1 may contribute to serotype‐associated differences in the biofilm‐forming capacity in L. monocytogenes. Significance and Impact of the Study: Parallel analysis of whole‐genome sequences and serotype‐specific data was performed to identify genetic markers that correlate with increased adherence and biofilm formation in L. monocytogenes. The analyses revealed the hitherto unrecognized role of SSI‐1 in biofilm formation, contributing to deeper understanding of genetic factors that influence behaviour of the species in the food processing environment.. Significance and Impact of the Study: Parallel analysis of whole‐genome sequences and serotype‐specific data was performed to identify genetic markers that correlate with increased adherence and biofilm formation in L. monocytogenes. The analyses revealed the hitherto unrecognized role of SSI‐1 in biofilm formation, contributing to deeper understanding of genetic factors that influence behaviour of the species in the food processing environment. [ABSTRACT FROM AUTHOR]

Abstract: Listeria monocytogenes is an opportunistic pathogen that has been involved in several deadly illness outbreaks. Future outbreaks may be more difficult to manage because of the emergence of antibiotic resistance among L. monocytogenes strains isolated from food products. The present review summarizes the available evidence on the emergence of antibiotic resistance among L. monocytogenes strains isolated from food products and the possible ways this resistance has developed. Furthermore, the resistance of food L. monocytogenes isolates to antibiotics currently used in the treatment of human listeriosis such as penicillin, ampicillin, tetracycline, and gentamicin, has been documented. Acquisition of movable genetic elements is considered the major mechanism of antibiotic resistance development in L. monocytogenes. Efflux pumps have also been linked with resistance of L. monocytogenes to some antibiotics including fluoroquinolones. Some L. monocytogenes strains isolated from food products are intrinsically resistant to several antibiotics. However, factors in food processing chains and environments (from farm to table) including extensive or sub‐inhibitory antibiotics use, horizontal gene transfer, exposure to environmental stresses, biofilm formation, and presence of persister cells play crucial roles in the development of antibiotic resistance by L. monocytogenes. [ABSTRACT FROM AUTHOR]

Antimicrobial surfaces are one approach to prevent biofilms in the food industry. The aim of this study was to investigate the effect of poly((tert-butyl-amino)-methyl-styrene) (poly(TBAMS)) incorporated into linear low-density polyethylene (LLDPE) on the formation of mono- and mixed-species biofilms. The biofilm on untreated and treated LLDPE was determined after 48 and 168 h. The comparison of the results indicated that the ability of Listeria monocytogenes to form biofilms was completely suppressed by poly(TBAMS) (Δ168 h 3.2 log10 cfu cm−2) and colonization of Staphylococcus aureus and Escherichia coli was significantly delayed, but no effect on Pseudomonas fluorescens was observed. The results of dual-species biofilms showed complex interactions between the microorganisms, but comparable effects on the individual bacteria by poly(TBAMS) were identified. Antimicrobial treatment with poly(TBAMS) shows great potential to prevent biofilms on polymeric surfaces. However, a further development of the material is necessary to reduce the colonization of strong biofilm formers. [ABSTRACT FROM AUTHOR]

Abstract: Controlling biofilm forming, pathogenic bacteria is an emerging challenge in the food industry, and the present study aims to test the efficacy of existing food preservation methods against these bacteria. We isolated 10 different biofilm forming pathogenic bacteria viz. Klebsiella quasipneumoniae, Bacillus cereus, Bacillus amyloliquefaciens, Bacillus anthracis, and Myroides odoratimimus from spoiled milk, biscuits, and cakes. K. quasipneumonia and B. amyloliquifaciens formed strong biofilm (OD550 > 0.85), whereas B. cereus, B. anthracis, and M. odoratimimus made moderate biofilm (OD5505 > 0.6) in 72 hr. The isolates, B. amyloliquifaciencs, B. anthracis, and M. odoratimimus were found positive for protease activity. The isolates showed significant tolerance to preservation conditions: pH (4–10), salt (up to 5%), temperature (up to 50°C) and sodium benzoate (up to 0.1%). The isolates also exhibited high antibiotic resistance, maximum by M. odoratimimus (MIC ≤ 256 µg/ml) against chloramphenicol which can have serious implications especially in tackling food borne illness caused by the biofilm forming food pathogens. Practical applications: The present study discloses the presence of biofilm forming pathogenic bacterial strains in common food stuff and their tolerance of preservation conditions and resistance to antibiotics. The occurrence of pathogens tolerant to common preservation conditions and their resistance to antibiotic should be addressed very cautiously. The significant findings of this study warrant the need for more stringent preservation methods to control food pathogens, especially the biofilm forming type. Moreover, findings of the present study will help to design novel preservation techniques such as incorporating antibiofilm coatings in food processing units and packaging materials, which will ensure food safety and public health. [ABSTRACT FROM AUTHOR]

The aim of this review is to provide a critical overview of the current knowledge of the differences between organic and conventional production regarding food safety. In general, it would appear that microbiological safety and contaminants from environmental and natural sources are greatly influenced by other factors rather than totally independent of the production systemper se. Claims that organic food is safer than conventional food have not yet been supported by definitive scientific research and, therefore, it can be concluded that the premium price of organic food may only be justifiable by factors other than food safety. [ABSTRACT FROM AUTHOR]

The foodborne pathogen Listeria monocytogenes is a concern in food safety because of its ability to form biofilm and to persist in food industry. In this mini-review, the issue represented by this pathogen and some of the latest efforts performed in order to investigate the composition of biofilms formed by L. monocytogenes are summarized. [ABSTRACT FROM AUTHOR]

Biofilms are microbial communities characterized by their adhesion to solid surfaces and the production of a matrix of exopolymeric substances, consisting of polysaccharides, proteins, DNA and lipids, which surround the microorganisms lending structural integrity and a unique biochemical profile to the biofilm. Biofilm formation enhances the ability of the producer/s to persist in a given environment. Pathogenic and spoilage bacterial species capable of forming biofilms are a significant problem for the healthcare and food industries, as their biofilm-forming ability protects them from common cleaning processes and allows them to remain in the environment post-sanitation. In the food industry, persistent bacteria colonize the inside of mixing tanks, vats and tubing, compromising food safety and quality. Strategies to overcome bacterial persistence through inhibition of biofilm formation or removal of mature biofilms are therefore necessary. Current biofilm control strategies employed in the food industry (cleaning and disinfection, material selection and surface preconditioning, plasma treatment, ultrasonication, etc.), although effective to a certain point, fall short of biofilm control. Efforts have been explored, mainly with a view to their application in pharmaceutical and healthcare settings, which focus on targeting molecular determinants regulating biofilm formation. Their application to the food industry would greatly aid efforts to eradicate undesirable bacteria from food processing environments and, ultimately, from food products. These approaches, in contrast to bactericidal approaches, exert less selective pressure which in turn would reduce the likelihood of resistance development. A particularly interesting strategy targets quorum sensing systems, which regulate gene expression in response to fluctuations in cell-population density governing essential cellular processes including biofilm formation. This review article discusses the problems associated with bacterial biofilms in the food industry and summarizes the recent strategies explored to inhibit biofilm formation, with special focus on those targeting quorum sensing. [ABSTRACT FROM AUTHOR]

Among food-borne pathogens, Listeria monocytogenes continues to pose concerns to food business operators due to its capacity to form biofilm in processing environments. Ozone may be an eco-friendly technology to control microbial contaminations, but data concerning its effect on Listeria monocytogenes biofilm are still limited. In this study, the effect of gaseous ozone at 50 ppm on planktonic cells and biofilm of reference and food-related Listeria monocytogenes strains was evaluated. Ozone caused a reduction in microbial loads of 3.7 ± 0.4 and 3.9 ± 0.4 Log10 CFU/mL after 10 and 30 min, respectively. A complete inactivation of planktonic cells after 6 h of treatment was observed. Biofilm inhibition and eradication treatments (50 ppm, 6 h) resulted in a significant decrease of the biofilm biomass for 59% of the strains tested, whilst a slight dampening of live cell loads in the biofilm state was observed. In conclusion, gaseous ozone is not sufficient to completely counteract Listeria monocytogenes biofilm, but it may be useful as an additional tool to contrast Listeria monocytogenes free-living cells and to improve the existing sanitization procedures in food processing environments. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a foodborne pathogen of special concern for ready-to-eat food producers. The control of its presence is a critical step in which food-grade sanitizers play an essential role. L. monocytogenes is believed to persist in food processing environments in biofilms, exhibiting less susceptibility to sanitizers than planktonic cells. This study aimed to test the susceptibility of L. monocytogenes in planktonic culture and biofilm to three commercial food-grade sanitizers and to benzalkonium chloride; together with the genetic subtyping of the isolates. L. monocytogenes isolates were collected from raw materials, final products and food-contact surfaces during a 6-year period from a ready-to-eat meat-producing food industry and genetically characterized. Serogrouping and pulsed-field gel electrophoresis (PFGE) revealed genetic variability and differentiated L. monocytogenes isolates in three clusters. The biofilm-forming ability assay revealed that the isolates were weak biofilm producers. L. monocytogenes strains were susceptible both in the planktonic and biofilm form to oxidizing and ethanol-based compounds and to benzalkonium chloride, but not to quaternary ammonium compound. A positive association of biofilm-forming ability and LD90 values for quaternary ammonium compound and benzalkonium chloride was found. This study highlights the need for preventive measures improvement and for a conscious selection and use of sanitizers in food-related environments to control Listeria monocytogenes. [ABSTRACT FROM AUTHOR]

Although conventional microbial control techniques are currently employed and largely successful, their major drawbacks are related to their effects on quality of processed food. In recent years, there has been a growing demand for high-quality foods that are microbially safe and retain most of their natural freshness. Therefore, several modern and innovative methods of microbial control in food processing have been developed. High-hydrostatic-pressure (HHP) processing technology has been mainly used to enhance the food safety of ready-to-eat (RTE) products as a new pre-/post-packaging, non-thermal purification method in the meat industry. Listeria monocytogenes is a pertinent target for microbiological safety and shelf-life; due to its capacity to multiply in a broad range of food environments, is extremely complicated to prevent in fermented-sausage-producing plants. The frequent detection of L. monocytogenes in final products emphasizes the necessity for the producers of fermented sausages to correctly overcome the hurdles of the technological process and to prevent the presence of L. monocytogenes by applying novel control techniques. This review discusses a collection of recent studies describing pressure-induced elimination of L. monocytogenes in fermented sausages produced in the Mediterranean area. [ABSTRACT FROM AUTHOR]