ArticlePDF Available

Assessment of the contamination potentials of some foodborne bacteria in biofilms for food products

Authors:

Abstract

Objective: To assess biofilms formed by different bacterial strains on glass slides, and changes in biofilm mass and biofilm-associated cell populations after brief contacts between biofilms and either media agar or food products. Methods: Two Listeria monocytogenes and Escherichia coli strains and a single Staphylococcus aureus strain were inoculated separately in tryptic soy broth containing glass coupons incubated for 24, 48 or 72 h at 37oC. The biofilms formed by individual bacterial strains and biofilm-associated cell populations were determined. Biofilms were subsequently allowed to have brief contacts (1-3 times), through gentle touching, with either agar, meat or soft white cheese (2 cm3). Changes in biofilm mass on glass slides and cell populations embedded in biofilms were quantified. Results: A nonpathogenic E. coli formed more biofilms than an E. coli O157:H7 strain. Biofilms formed by S. aureus and L. monocytogens were essentially similar. The biofilm mass increased as incubation time increased within 48 h of incubation and was not positively correlated with cellulose production. Biofilm mass at 48 and 72 h of incubation was not significantly different. More frequent contacts with agar or foods did not remove more biofilms or biofilm-associated cells from glass slides. More S. aureus biofilms were removed followed by Listeria and E. coli biofilms. Mean contamination of agar or food models was 0.00 to 7.65 logCFU/cm2. Greater contaminations in cell populations were observed with S. aureus and Listeria biofilms. Conclusion: The results provide a clearer assessment of contaminating potential of foods that comes in contact with them.
A preview of the PDF is not available
... The CLSM findings revealed that as the culture time progressed, fewer and fewer live bacteria were detected until all of them were dead. This decrease in cell number is most likely due to death caused by waste build-up and nutritional starvation, which result in environmental changes, including decreased pH, and metabolic disturbances (Adetunji et al., 2014;Pan et al., 2010). We can avoid excess carbohydrate discharge into the environment and prevent and control colibacillosis in poultry by studying the effects of carbohydrates on biofilms. ...
Article
Full-text available
Aims: To study the effects of environmental stress and nutrient conditions on biofilm formation of avian pathogenic Escherichia coli (APEC). Methods and results: The APEC strain DE17 was used to study biofilm formation under various conditions of environmental stress (including different temperatures, pH, metal ions, and antibiotics) and nutrient conditions (LB and M9 media, with the addition of different carbohydrates, if necessary). The DE17 biofilm formation ability was strongest at 25°C in LB medium. Compared to incubation at 37°C, three biofilm-related genes (csgD, dgcC, and pfs) were significantly upregulated and two genes (flhC and flhD) were downregulated at 25°C, which resulted in decreased motility. However, biofilm formation was strongest in M9 medium supplemented with glucose at 37°C, and the number of live bacteria was the highest as determined by confocal laser scanning microscopy (CLSM). The bacteria in the biofilm were surrounded by a thick extracellular matrix, and honeycomb-like or rough surfaces were observed by scanning electron microscopy (SEM). Moreover, biofilm formation of the DE17 strain was remarkably inhibited under acidic conditions, whereas neutral and alkaline conditions were more suitable for biofilm formation. Biofilm formation was also inhibited at specific concentrations of cations (Na+ , K+ , Ca2+ , and Mg2+ ) and antibiotics (ampicillin, chloramphenicol, kanamycin, and spectinomycin). The qRT-PCR showed that the transcription levels of biofilm-related genes change under different environmental conditions. Conclusions: Nutritional and environmental factors played an important role in DE17 biofilm development. The transcription levels of biofilm-related genes changed under different environmental and nutrient conditions. Significance and impact of the study: The findings suggest that nutritional and environmental factors play an important role in APEC biofilm development. Depending on the different conditions involved in this study, it can serve as a guide to treating biofilm-related infections and to eliminating biofilms from the environment.
... Biofilms are more resistant to environmental stresses, such as UV light exposure, sanitising agents, nutritional and oxidative stresses, and desiccation. Consequently, biofilms are important for both public health and the economy because they cause chronic illnesses that are challenging to cure and are resistant to cleaning and sanitation [120]. ...
Article
Full-text available
Biofilms are microbial aggregation membranes that are formed when microorganisms attach to the surfaces of living or nonliving things. Importantly, biofilm properties provide microorganisms with protection against environmental pressures and enhance their resistance to antimicrobial agents, contributing to microbial persistence and toxicity. Thus, bacterial biofilm formation is part of the bacterial survival mechanism. However, if foodborne pathogens form biofilms, the risk of foodborne disease infections can be greatly exacerbated, which can cause major public health risks and lead to adverse economic consequences. Therefore, research on biofilms and their removal strategies are very important in the food industry. Food waste due to spoilage within the food industry remains a global challenge to environmental sustainability and the security of food supplies. This review describes bacterial biofilm formation, elaborates on the problem associated with biofilms in the food industry, enumerates several kinds of common foodborne pathogens in biofilms, summarizes the current strategies used to eliminate or control harmful bacterial biofilm formation, introduces the current and emerging control strategies, and emphasizes future development prospects with respect to bacterial biofilms.
... Because the creation of microbial biofilm on surfaces has such a substantial impact on food quality and safety in contact with food, the production of microbial biofilm on surfaces might be considered the most serious problem in the food industry [7]. Biofilm formation is one of the primary and most serious challenges in the food industry, notably in the beer, dairy, red meat, poultry, and fish industries, as there have been several cases of food contamination as a result of contact with biofilm contaminated surfaces [8]. Bacterial pathogens, which are particularly important in food safety, are among the microorganisms that create biofilms in food manufacturing environments. ...
Article
Full-text available
Objectives: Biofilms formed in food-processing environments are of special importance as they have the potential to act as a persistent source of microbial contamination that may lead to food spoilage or transmission of diseases. The creation of microbial biofilms, which can be a source of food product contamination with food spoilage and food borne pathogenic bacteria, is one of the most critical elements in the food industry. The goal of this study was to see how well magnesium oxide (MgO) and copper oxide (CuO) nanoparticles (NPs) inhibited growth and biofilm formation of two common foodborne bacterial pathogens. Methods and results: This study was completed in the year 2020. Resazurin reduction and micro-dilution procedures were used to assess the minimum inhibitory concentration (MIC) of magnesium oxide and copper oxide nanoparticles for Escherichia coli O157: H7 (ATCC 35218) and Listeria monocytogenes (ATCC 19118). The bacterial adhesion to hydrocarbon technique was used to determine the cell-surface hydrophobicity of the selected bacteria. The surface assay was also used to calculate the influence of the NPs coated surfaces on the biofilm formation of the selected bacteria. Magnesium oxide nanoparticles had MICs of 2 and 2 mg/ml, while copper oxide nanoparticles had MICs of 0.16 and 1 mg/ml against E. coli and L. monocytogenes, respectively. At the MIC, the magnesium and copper nanoparticles inhibited biofilm formation of E. coli and L. monocytogenes by 89.9 and 96.6 percent and 93.6 and 98.7 percent, respectively. The hydrophobicity of E. coli and L. monocytogenes was determined to be 74% and 67%, respectively. The surface assay revealed a substantial reduction in bacterial adhesion and colonization on NPs-coated surfaces. Conclusions: Both compounds had inhibitory effects on E. coli and L. monocytogenes, according to our findings. Even at sub-MICs, NPs were found to be able to prevent biofilm development. The microbial count and production of microbial biofilms were reduced on surfaces coated with MgO and CuO nanoparticles.
... Biofilms are able to increase the survival of bacteria, having a protective effect against host defence mechanisms [53]. This bacterial ability has also been associated with an increase in the persistence of the pathogen in the food industry [54,55]. Similarly to those described by Ferreira et al. (2013), our results demonstrate a general increase in the ability of biofilm formation under microaerobic conditions when compared to aerobic conditions [56]. ...
Article
Full-text available
Arcobacter butzleri is an emergent gram-negative enteropathogenic bacterium widespread in different environments and hosts. During the colonization of the gastrointestinal tract, bacteria face a variety of environmental conditions to successfully establish infection in a new host. One of these challenges is the fluctuation of oxygen concentrations encountered not only throughout the host gastrointestinal tract and defences but also in the food industry. Oxygen fluctuations can lead to modulations in the virulence of the bacterium and possibly increase its pathogenic potential. In this sense, eight human isolates of A. butzleri were studied to evaluate the effects of microaerobic and aerobic atmospheric conditions in stressful host conditions, such as oxidative stress, acid survival, and human serum survival. In addition, the effects on the modulation of virulence traits, such as haemolytic activity, bacterial motility, biofilm formation ability, and adhesion and invasion of the Caco-2 cell line, were also investigated. Overall, aerobic conditions negatively affected the susceptibility to oxygen reactive species and biofilm formation ability but improved the isolates’ haemolytic ability and motility while other traits showed an isolate-dependent response. In summary, this work demonstrates for the first time that oxygen levels can modulate the potential pathogenicity of A. butzleri, although the response to stressful conditions was very heterogeneous among different strains.
... When formed on food contact surfaces and/or materials, biofilms increase food safety risk. Reservoirs of food spoilage and/or pathogen bacteria in food industries are an important cause of product contamination that can lead not only to a reduced shelf life of foods, but also to health problems (Abebe, 2020;Adetunji et al., 2014). Therefore, the biofilm formation by food derived Arcobacter spp. ...
Article
Full-text available
Various species of the genus Arcobacter are regarded as emerging food pathogens and can be cause of human gastroenteric illness, among others. In order to gain knowledge on the risk associated with the presence of arcobacters in retail foods, this study aimed to determine their presence in a variety of products; to evaluate the genetic diversity and the occurrence of virulence and biofilm-associated genes in the isolated strains; and to assess their biofilm activity on polystyrene, borosilicate and stainless steel. Arcobacters were detected in the 22.3% of the analysed samples and the 83 recovered isolates were identified as A. butzleri (n = 53), A. cryaerophilus (n = 24), A. skirrowii (n = 2), A. thereius (n = 3) and A. vitoriensis (n = 1). They were isolated from virtually all tested food types, but mostly from squids and turkey meat (contamination levels of 60% and 40%, respectively). MLST differentiated 68 STs, most of which were novel (89.7%) and represented by a single strain (86.9%). Five novel STs were detected in various isolates derived from seafood, and the statistical analysis revealed their potential association with that type of food product (p < 0,001). All the isolates except one harboured virulence-associated genes and the highest incidence was noted for A. butzleri. Nineteen isolates (23.5%) were able to form biofilms on the different surfaces tested and, of note; glass enhanced the adhesion ability of the majority of them (84.2%). The results highlight the role that common food products can have in the transmission of Arcobacter spp., the pathogenic potential of the different species, and the survival and growth ability of several of them on different food contact surfaces. Therefore, the study provides interesting information regarding the risk arcobacters may pose to human health and the food industry.
... Such is the case for food industries, where organic and inorganic residues accumulate on food contact materials and surfaces. Biofilms formed on food processing surfaces are a great concern because the hygiene of the surfaces affects the quality and safety of the food products (2). They can result in product contamination that may lead to health problems if they are constituted by pathogenic bacteria (25). ...
Article
Full-text available
The transmission of Arcobacter butzleri , an emerging food- and waterborne pathogen, is possibly favored by its ability to adhere to abiotic surfaces. In this study, we assessed the biofilm formation ability of 42 A. butzleri isolates recovered from different food products. Overall, nine isolates (21.4%) were able to adhere to polystyrene. Among them, a chicken-derived isolate was classified as strongly adherent. Based on the chi-square test, no relation was found between the adhesive abilities of the isolates and their source (P > 0.05). An aerobic atmosphere enhanced the adhesion ability of the majority of the adherent isolates (66.7%), because when tested in microaerobic conditions, a t test indicated that only three isolates increased their biofilm formation ability significantly (P < 0.05). In addition, seven (77.8%) of these nine isolates were able to adhere to glass surfaces, and viable cells were recovered from all the stainless steel coupons tested. Therefore, our results confirm the biofilm formation ability of A. butzleri , which may be influenced by the incubation atmosphere and the abiotic surface.
Article
Full-text available
The indiscriminate slaughter of pregnant animals which characterizes most developing countries poses increasing environmental and public health risks from Listeria monocytogenes infections which are endemic in such settings. The available reports show increasing trends of Listeria monocytogenes infections in both humans and animals in Nigeria. This study examined the prevalence, antibiogram and biofilm production of L. monocytogenes from faeces and foetuses of slaughtered pregnant cows in Ibadan Central Abattoir, Nigeria. Faecal (n = 118) and foetal (n = 118) swabs were cultured and isolates tested for antibiotic susceptibility by Kirby-Bauer assay, while biofilm production was quantified following the standard procedures. The data were analysed using the Chi Square and Student’s t-test at P < 0.05. Listeria monocytogenes were isolated from five (4.2 %) and three (2.5 %) faeces and foetus swabs, respectively, without significant association with sample type (P = 0.50). The isolates were resistant to all the antibiotics tested except gentamicin; with significantly higher production of biofilm by those from foetal samples (P = 0.012). The detection of widespread antibiotic-resistant L. monocytogenes from faeces and foetuses has important environmental and public health implications, given the risk of contamination through faecal shedding and foetal handling. The biofilm production by the pathogen connotes its ability to persist in the environment, suggestive of the challenging effects to its control. Campaigns against indiscriminate slaughter of pregnant animals, and proper hygiene are advocated to ultimately safeguard human and animal health.
Article
Despite food safety criteria for some specific foodborne pathogens that exist all over the world, the prevalence of Staphylococcus aureus in raw milk cheese is high. The biofilm formation capacity of S. aureus ATCC25923 in Minas Frescal cheese packaging at 5 °C was investigated. Surface adhesion and quantification of viable adherent cells, detachment of adherent cells, biofilm viable cell count during long incubation periods and total cell count were investigated. Biofilm formation and detachment of viable cells during storage occurred at all times studied in the presence of whey. Thus, improvements in the hygiene of the packaging process are strongly recommended. Studing the Staphylococcus aureus biofilm formation in Minas Frescal cheese packaging.
Article
Full-text available
This paper is a part of a multidisciplinary research "Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins". 130 one day old broiler chicks were divided into five groups. Chickens were reared on potable water, treated sewage water, and sewage water at different concentrations (30, 70 and 100 %) and were slaughtered after 21 and 35 days of rearing. Histopathological examination of liver, kidneys, bursa of Fabricuis, spleen, thymus, crop, gizzard, proventriculus and intestine was performed. Meat samples were taken from thighs and breasts of chickens for bacteriological and sensory analysis. The histopathological examination revealed that the most affected organs in the groups drinking sewage water were the kidneys and intestine whereas lesions seen in the crop, proventriculous and gizzard were similar in the tested groups. The results of bacteriological analysis showed that all investigated bacterial counts (aerobic plate count, Enterobacteriaceae, coliforms and fecal coliforms) were higher than the limit standardized by the Egyptian standard specifications in young and old chicken meat reared on sewage water at concentrations of 70 and 100 %. The results of sensory analysis revealed that meat samples obtained from chicken reared on 70 and 100 % sewage water had flavor and overall acceptability scores lower than the acceptable level and dark meat color. In conclusion, Drinking treated sewage water had less serious impact on health and meat quality of chickens compared to the use of untreated SW in chickens.
Article
Full-text available
This paper is a part of a multi-disciplinary research “Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins”. 130 one day old broiler chicks were divided into five groups. Chickens were reared on potable water, treated sewage water, and sewage water at different concentrations (30, 70 and 100 %) and were slaughtered after 21 and 35 days of rearing. Histopathological examination of liver, kidneys, bursa of Fabricuis, spleen, thymus, crop, gizzard, proventriculus and intestine was performed. Meat samples were taken from thighs and breasts of chickens for bacteriological and sensory analysis. The histopathological examination revealed that the most affected organs in the groups drinking sewage water were the kidneys and intestine whereas lesions seen in the crop, proventriculous and gizzard were similar in the tested groups. The results of bacteriological analysis showed that all investigated bacterial counts (aerobic plate count, Enterobacteriaceae, coliforms and fecal coliforms) were higher than the limit standardized by the Egyptian standard specifications in young and old chicken meat reared on sewage water at concentrations of 70 and 100 %. The results of sensory analysis revealed that meat samples obtained from chicken reared on 70 and 100 % sewage water had flavor and overall acceptability scores lower than the acceptable level and dark meat color. In conclusion, Drinking treated sewage water had less serious impact on health and meat quality of chickens compared to the use of untreated SW in chickens.
Article
Full-text available
Quantification of biofilm formation by 40 Listeria monocytogenes strains from wara soft cheese and its processing environment was assessed on glass vials surfaces. Attachement to glass surface was quantified using a crystal violet binding assay. All the 40 strains produced biofilms after 48 and 72 h incubation at 37°C. No biofilms were formed at 24 h incubation but biofilm formation increased with incubation period in 20 out of the 40 strains. R2 values obtained were 0.0166 and 0.1193 respectively for biofilm formation between 24 and 48 h and 24 and 72 h incubation periods, respectively (P-values of < 0.05*). L. monocytogenes strains isolated from wara cheese were generally sensitive to augmentin, streptomycin, claforan, erythromycin, gentamycin, septrin, tarivid, and rocephine and were highly resistant to nitrofuran, fortum, zinnat, and tetracycline. The enhancement of biofilm formation in L. monocytogenes strains from 'wara' in this study suggests a relationship with pathogenicity in foodborne isolates. The transfer of antibiotic resistant L. monocytogenes to human via the food chain is a significant health concern.
Article
Full-text available
Micro-organisms attach to surfaces and develop biofilms which are a concern in food and environmental safety. This study, quantified biofilms in 20 isolates viz: Listeria monocytogenes (14) and Listeria spp (6) from meat tables in Ibadan municipal abattoir, Nigeria on wood, glass and steel surfaces using crystal-violet binding assay. Listeria isolates formed biofilms on all three surfaces. At 24hours Listeria monocytogenes(SLM) formed more biofilms on wood(0.22±0.01) and glass(0.09±0.01) surfaces than Listeria spp(SLS) which was wood(0.17±0.02) and glass (0.06±0.01). But the reverse was the case on steel where Listeria spp (SLS) formed more biofilms (0.11±0.01) than Listeria monocytogenes (SLM) (0.10±0.00). A significant difference (P<0.01) exists between isolates for wood and glass at 24hours and (P<0.05) for wood at 72hours. Significant differences (P<0.05) occured in biofilms produced between 24hours and 72hours. It can be concluded that selection of suitable surfaces could reduce the ability of bacteria forming biofilms on meat contact-surfaces. This finding is very relevant in developing countries where wood is still in use as a major meat contact-surface in abattoirs.
Article
Full-text available
Mycobacterium bovis causes classic bovine tuberculosis, a zoonosis which is still a concern in Africa. Biofilm forming ability of two Mycobacterium bovis strains was assessed on coupons of cement, ceramic, or stainless steel in three different microbiological media at 37°C with agitation for 2, 3, or 4 weeks to determine the medium that promotes biofilm. Biofilm mass accumulated on coupons was treated with 2 sanitizers (sanitizer A (5.5 mg L(-1) active iodine) and sanitizer B (170.6 g(1) alkyl dimethylbenzyl ammonium chloride, 78 g(-1) didecyldimethyl ammonium chloride, 107.25 g L(-1) glutaraldehyde, 146.25 g L(-1) isopropanol, and 20 g L(-1) pine oil) at 28 and 45°C and in hot water at 85°C for 5 min. Residual biofilms on treated coupons were quantified using crystal violet binding assay. The two strains had a similar ability to form biofilms on the three surfaces. More biofilms were developed in media containing 5% liver extract. Biofilm mass increased as incubation time increased till the 3rd week. More biofilms were formed on cement than on ceramic and stainless steel surfaces. Treatment with hot water at 85°C reduced biofilm mass, however, sanitizing treatments at 45°C removed more biofilms than at 28°C. However, neither treatment completely eliminated the biofilms. The choice of processing surface and temperatures used for sanitizing treatments had an impact on biofilm formation and its removal from solid surfaces.
Article
Full-text available
This study assessed the biofilms formed by selected strains of Mycobacterium tuberculosis and investigated the efficacy of three different treatments to control the biofilms. Two M. tuberculosis strains were inoculated separately in 150 ml of Middlebrook 7H9-Tween 80 (0.1%) broth with 5% liver extract and 10% oleic albumin dextrose catalase (OADC) supplement, 5% liver extract alone, or 10% OADC alone in sterile jars, each containing a 2-cm(2) coupon of cement, ceramic, or stainless steel for biofilm development at 37°C, with agitation for 2, 3, or 4 weeks. Biofilms on the coupons were exposed to 10 ml of 2% sanitizer A or 0.5% sanitizer B at 28 and 45°C and to hot water at 85°C for 5 min. Residual biofilms on treated and untreated coupons were assessed. Both strains of M. tuberculosis formed biofilms on the three surfaces; however, one strain formed more biofilms. More biofilms were formed when media containing 5% liver extract was used. Biofilm mass increased as incubation time increased until the third week. More biofilms were formed on cement than on ceramic and stainless steel coupons. Sanitizing treatments at 45°C removed more biofilms than those at 28°C. However, neither treatment completely eliminated the biofilms.
Article
Biofilms in the food-processing industry are a serious concern due to the potential for contamination of food products, which may lead to decreased food quality and safety. The effect of two detergent and sanitizer combinations on the inactivation of Listeria monocytogenes biofilms was studied. Combination A uses a chlorinated-alkaline, low-phosphate detergent, and dual peracid sanitizer. Combination B uses a solvated-alkaline environmental sanitation product and hypochlorite sanitizer. The survival of bacterial biofilms placed at 4 and 10degreesC and held for up to 5 days was also addressed. To simulate conditions found in a ready-to-eat meat-processing environment, biofilms were developed in low-nutrient conditions at 10degreesC (with and without meat and fat residue) on a variety of materials found in a plant setting. Included were two types of stainless steel, three materials for conveyor use, two rubber products, a wall, and floor material. Biofilms developed on all surfaces tested; numbers at day 2 ranged from 3.2 log on silicone rubber to 4.47 log CFU/cm(2) on Delrin, an acetal copolymer. Biofilm survival during storage was higher at 4degreesC (36.3 to 1,621%) than 10degreesC (4.5 to 83.2%). Small amounts of meat extract, frankfurters, or pork fat reduced biofilm formation initially; with time, the biofilm cell number and survival percentage increased. Cleaning efficacy was surface dependent and decreased with residue-soiled surfaces; biofilms developed on the brick and conveyor material were most resistant. Both detergents significantly (P < 0.05) removed or inactivated biofilm bacteria. The sanitizers further reduced biofilm numbers; however, the reduction was not significant in most cases for the dual peracid. Using a benchmark efficacy of >3-log reduction, combination A was only effective on 50.0% of the samples. Combination B, at 86.1%, was more effective.
Article
Listeria monocytogenes (L. monocytogenes) is a gram positive food-borne pathogen that is able to form biofilm on food factory surfaces. Formation of biofilm makes the bacteria much more resistance to environmental stresses such as disinfectant. The extracellular polymeric matrix (biofilm structure) which is mostly comprised of sticky extracellular polysaccharides (EPS) and proteins can protect bacteria in a harsh condition. The efficiency of four disinfectants on removing L. monocytogenes biofilm was investigated. Five concentration levels (100, 50, 25, 12.5, and 6.25%) of disinfectants were tested. In the microtitre assay, the optical density at 595 nm CV-OD595 value, was used to measure the amount of remained biofilm after 24 h. Results showed that disinfectants did not have significant effect on removing L. monocytogenes biofilm. Formation of L. monocytogenes biofilm significantly decreased the efficiency of disinfectants. Biofilm produced by strain number 9 showed higher resistance to disinfectant. Low concentrations (<50%) of disinfectants did not show significant effect on removing L. monocytogenes biofilm.
Article
Food safety has implications for both the health of individuals and the economic development of societies. Although most countries have had functioning food safety systems for many years, foodborne disease continues to be a major public health issue. Although food safety systems have not succeeded completely in disease prevention, recent decades have seen significant new developments in food production and control philosophies aimed at improvement of the efficiency of food safety systems in many countries. However, future decades will most likely see even more dramatic changes in this area. New approaches will be anchored in the risk analysis framework, using risk assessments based on relevant scientific data. Such data are likely to be significantly different from traditional control data and will thus present us with different analytical needs, most likely including needs for very specific identification systems working in real-time settings. Coherent, science-based strategies will enable action plans to lower the prevalence of relevant hazards (e.g., pathogens) in animals and/or food. Lowering the concentration or the prevalence of these pathogens should be governed by food safety objectives, enabling a continuous reduction of problems over time. Chemical hazards are increasingly comparable with such microbiological contaminants. Chemical contaminants, such as fungal toxins or acrylamide, need to be dealt with in a sequential manner, reducing the levels over time to improve health. The novelty of the risk analysis concept is that risks are assessed throughout the food chain on the basis of sound science, by combining qualitative and quantitative data in the areas of epidemiology and pathogenicity of microorganisms with data from disease surveillance and food monitoring. It is likely that future surveillance of microbiological foodborne disease will increasingly be based on molecular and gene sequence based subtyping, enabling the identification of widespread outbreaks not recognized previously.