Inactivation of murine norovirus 1 and Bacteroides fragilis phage B40-8 by mesophilic and thermophilic anaerobic digestion of pig slurry.

Mesophilic (37 degrees C) and thermophilic (52 degrees C) anaerobic digestion of pig slurry induced at least a 4-log decrease in murine norovirus 1, used as a surrogate virus for porcine norovirus, after 13 and 7 days, respectively. Bacteroides fragilis phage B40-8, employed as a universal viral model, was lowered by 2.5 log after 7 days. The viral titer declined due to temperature and matrix effects.

Comparing the effect of various contamination levels for salmonella in chicken meat preparations on the probability of illness in belgium.

At the urging of competent national authorities, a limited risk assessment on Salmonella in chicken meat preparations in Belgium was undertaken following a retail-to-table approach. The input distribution of Salmonella was based on surveillance data in Belgium. To analyze the relative impact of reducing the risk of salmonellosis associated with a decrease in the Salmonella contamination level, different distributions based on the actual situation but limiting the number of portions containing Salmonella at 1 CFU per 1, 10, and 25 g of meat were used in the quantitative microbial risk assessment model. The quantitative microbial risk assessment model also was run several times with a theoretical fixed input of Salmonella assuming all portions possessed the same fixed contamination level set at 1,000, 100, 10, and 1 CFU/g of meat and 1 CFU per 10, 25, 100, and 1,000 g of meat. With regard to the initial contamination level, the results indicate, both by the narrowing of the current distribution and by the fixed input, that especially the higher levels of contamination (>1 CFU/g) contribute to the increased risk for salmonellosis.

Characterization of Escherichia coli from raw poultry in Belgium and impact on the detection of Campylobacter jejuni using Bolton broth.

A comparative study examining Bolton broth and Preston broth for enrichment and reliable detection of Campylobacter jejuni (both healthy and freeze stressed cells) was performed. Tested as pure cultures, Bolton broth enabled faster resuscitation and growth of C. jejuni compared to Preston broth. When C. jejuni was co-incubated with extended-spectrum-beta-lactamase (ESBL) producing Escherichia coli isolated from Belgian poultry meat preparations, the latter dominated in the Bolton enrichment broth and crowded the mCCDA plates. This resulted in the inability to recover C. jejuni by ISO 10272-1:2006 standard method. Preston broth did not support the growth of the ESBL E. coli isolates, but showed longer detection time of C. jejuni compared to Bolton broth. The use of the same antibiotic (sodium cefoperazone) in Bolton broth and in mCCDA plates may explain the problems encountered for detection of C. jejuni, as high numbers of ESBL E. coli present after enrichment in Bolton broth, also caused overgrowth and masked the few C. jejuni colonies present on the mCCDA plates. The use of Campylobacter spp. specific real-time PCR circumvented these problems and enabled rapid detection of the pathogen after 24h enrichment in both Bolton and Preston broth, for both healthy and freeze stressed cells.

Comparison of enrichment conditions for rapid detection of low numbers of sublethally injured Escherichia coli O157 in food.

A comparative study of lag phases and growth rates of healthy, stressed, and sublethally injured Escherichia coli O157 cells in 10 enrichment broths was performed. The evaluation of enrichment protocols was validated by different end point detection methods (two PCR and two combined capture-plate methods). Tryptic soy broth b [TSB (b)] provided the fastest growth (max = 1.00 1 0.06 h- ) but failed to recover oxidative-stressed E. coli O157. TSB (a), TSB-yeast extract medium, TSB supplemented with 8 mg/liter novobiocin plus 16 mg/liter vancomycin (TSB+), buffered peptone water (BPW), and BPW supplemented with 8 mg/liter vancomycin (BPW+V) enabled resuscitation of E. coli O157 cells independent from precultural conditions. Modified TSB plus 10 mg/liter novobiocin (mTSB+N), EC medium, EC reduced bile salts medium (ECred), TSB (b), and TSB supplemented with 8 mg/liter novobiocin plus 16 mg/liter vancomycin plus 2 mg/liter rifampin plus 1 mg/liter K-Telluriet plus 1.5 g/liter bile salts no. 3 (TSB++) all failed to recover E. coli O157 cells for at least one type of stress. The use of TSB (a), TSB+, BPW, and BPW+V was compared with that of mTSB+N (International Organization for Standardization reference broth) for reliable detection of low numbers of healthy, stressed, and sublethally injured E. coli O157 (approximately 10 CFU/10 g) from foods (sprouted seeds, fermented sausage, raw milk, and raw ground beef). When low numbers of healthy cells were inoculated, BPW, BPW+V, TSB, TSB+, and mTSB+N enabled growth until detectable numbers within 6 h of enrichment at 41.5 degrees C. Results showed that mTSB+N failed to recover to detectable numbers E. coli O157 cells sublethally injured by freeze and food stresses, in contrast to what was obtained with BPW and BPW+V. This study highlights that using mTSB+N for recovery of E. coli O157 from foods may yield false-negative results.

Efficacy of sodium hypochlorite and peroxyacetic acid to reduce murine norovirus 1, B40-8, Listeria monocytogenes, and Escherichia coli O157:H7 on shredded iceberg lettuce and in residual wash water.

The efficiency of sodium hypochlorite (NaOCl) and peroxyacetic acid (PAA) to reduce murine norovirus 1 (MNV-1), a surrogate for human norovirus, and Bacteroides fragilis HSP40-infecting phage B40-8 on shredded iceberg lettuce was investigated. The levels of removal of viruses MNV-1 and B40-8 were compared with the reductions observed for bacterial pathogens Listeria monocytogenes and Escherichia coli O157:H7. Two inoculation levels, one with a high organic load and the other containing a 10-fold lower number of pathogens and organic matter, showed that the effectiveness of NaOCl was greatly influenced by the presence of organic material, which was not observed for PAA. Moreover, the present study showed that 200 mg/liter NaOCl or 250 mg/liter PAA is needed to obtain an additional reduction of 1 log (compared with tap water) of MNV-1 on shredded iceberg lettuce, whereas only 250 mg/liter PAA achieved this for bacterial pathogens. None of the treatments resulted in a supplementary 1-log PFU/g reduction of B40-8 compared with tap water. B40-8 could therefore be useful as an indicator of decontamination processes of shredded iceberg lettuce based on NaOCl or PAA. Neither MNV-1, B40-8, nor bacterial pathogens could be detected in residual wash water after shredded iceberg lettuce was treated with NaOCl and PAA, whereas considerable numbers of all these microorganisms were found in residual wash water consisting solely of tap water. This study illustrates the usefulness of PAA and NaOCl in preventing cross-contamination during the washing process rather than in causing a reduction of the number of pathogens present on lettuce.

Kinetics of resuscitation and growth of L. monocytogenes as a tool to select appropriate enrichment conditions as a prior step to rapid detection methods.

Rapid methods still rely on a prior (shortened) enrichment step before application. Quantitative information is a prerequisite for understanding the resuscitation kinetics of the growth during the enrichment step. In this study various basal and newly introduced selective enrichment broths were evaluated. First, growth parameters (lambda, mu(max)) of both healthy and sub-lethally injured cells were determined. Next, a selection of enrichment broths was compared for their capacity to support detection within 24h of low numbers of Listeria monocytogenes in artificially and naturally contaminated food samples. Detection was performed either by phage protein-based capture (Listeria Capture kit, Profos, Regensburg, Germany) combined with plating on chromogenic medium or by fluorescence in situ hybridization (FISH) using the VIT-Listeria kit (Vermicon, Munich, Germany). Kinetics of resuscitation and growth of L. monocytogenes in various enrichment broths showed that for detection of low numbers of sub-lethally injured L. monocytogenes cells at least an overnight enrichment was needed. A selective enrichment broth was needed to enable proliferation of L. monocytogenes within the indigenous bacterial flora present in foods. However, combination of an appropriate enrichment condition with advanced detection techniques may enable a 24h detection of L. monocytogenes.

Survival and transfer of murine norovirus 1, a surrogate for human noroviruses, during the production process of deep-frozen onions and spinach.

The reduction of murine norovirus 1 (MNV-1) on onions and spinach by washing was investigated as was the risk of contamination during the washing procedure. To decontaminate wash water, the industrial sanitizer peracetic acid (PAA) was added to the water, and the survival of MNV-1 was determined. In contrast to onions, spinach undergoes a heat treatment before freezing. Therefore, the resistance of MNV-1 to blanching of spinach was examined. MNV-1 genomic copies were detected with a real-time reverse transcription PCR assay in PAA-treated water and blanched spinach, and PFUs (representing infectious MNV-1 units) were determined with a plaque assay. A < or = 1-log reduction in MNV-1 PFUs was achieved by washing onion bulbs and spinach leaves. More than 3 log PFU of MNV-1 was transmitted to onion bulbs and spinach leaves when these vegetables were washed in water containing approximately 5 log PFU/ml. No decline of MNV-1 occurred in used industrial spinach wash water after 6 days at room temperature. A concentration of 20 ppm of PAA in demineralized water (pH 4.13) and in potable water (pH 7.70) resulted in reductions of 2.88 +/- 0.25 and 2.41 +/- 0.18 log PFU, respectively, after 5 min of exposure, but no decrease in number of genomic copies was observed. No reduction of MNV-1 PFUs was observed on frozen onions or spinach during storage for 6 months. Blanching spinach (80 degrees C for 1 min) resulted in at least 2.44-log reductions of infectious MNV-1, but many genomic copies were still present.

Decontamination methods to prolong the shelf-life of minimally processed vegetables, state-of-the-art.

Minimally processed vegetables (MPV) are any fresh vegetables that have been physically altered from their original form, but remains in a fresh state. Microorganisms present in MPV can cause foodborne illnesses or spoilage; hence, decontamination of MPV can produce more stable products. The present review examines the difficulties to decontaminate and prolong the shelf-life of MPV, evaluating the current way of data analysis and interpretation. It addresses the different aspects of the problem of the accessibility of sanitizers to microorganisms (irregularities of produce surface, injuries, internalization, attachment, and biofilms). It also includes a critical exposition of the methodological problems to estimate the prolongation of shelf-life due to a decontamination method, namely: the variability among samples, the reproducibility of the results, and the interpolation when lacking some crucial data. Furthermore, it revises the difficulties to control the microbial loads of decontaminated MPV during storage (the enhanced growth rate of microorganisms in decontaminated MPV, the patterns of microbial growth in non decontaminated and decontaminated MPV, and the role of temperature in keeping the decontamination effect).

Multi-method approach indicates no presence of sub-lethally injured Listeria monocytogenes cells after mild heat treatment.

Application of mild inactivation treatments follows an increasing trend in the food industry and is often combined with sub-optimal intrinsic product conditions to ensure appropriate level of microbial safety. Listeria monocytogenes was subjected to mild heat treatment (20 min at 60 degrees C) and subsequently exposed to various mild preservation conditions based on increased NaCl concentration and decreased pH. Recovery and resuscitation of L. monocytogenes cells were studied using various methods. Using 12-fold Most Probable Number (MPN) method no difference in the amount of recovered cells under adverse conditions was noted between heat-treated and non-treated L. monocytogenes cells. Time-to-detection method using on-line OD measurements showed that heat-treated L. monocytogenes cells reached detection limit faster in acidified media and NaCl supplemented media in comparison with non-heated control cells. Flow cytometry (FCM) analysis using 5-6-carboxyfluorescein diacetate (cFDA) and propidium iodide (PI) staining showed presence of low numbers of viable cells. Overall, there was no indication of sub-lethal injury in L. monocytogenes cells after mild heat treatment.

Evaluation of viral extraction methods on a broad range of Ready-To-Eat foods with conventional and real-time RT-PCR for Norovirus GII detection.

Noroviruses (NoV) are a common cause of foodborne outbreaks. In spite of that, no standard viral detection method is available for food products. Therefore, three viral elution-concentration methods and one direct RNA isolation method were evaluated on a broad range of Ready-To-Eat (RTE) food products (mixed lettuce, fruit salad, raspberries and two RTE dishes) artificially seeded with a diluted stool sample contaminated with NoV genogroup II. These seeding experiments revealed two categories of RTE products, fruits and vegetables grouped together and RTE dishes (penne and tagliatelle salads) which are rich in proteins and fat formed another category. The RNA extracts were amplified and detected with two conventional RT-PCR systems (Booster and Semi-nested GII) and one real-time RT-PCR (Real-time GII) assay. A fast direct RNA isolation method detected 10(2) RT-PCRU on 10 g penne and tagliatelle salads with the conventional RT-PCR assays. However real-time RT-PCR was less sensitive for penne salad. A viral elution-concentration method, including a buffer solution for the elution step and one polyethylene glycol (PEG) precipitation step, was able to detect 10(2) RT-PCRU on 50 g frozen raspberries with conventional and real-time RT-PCR assays. Moreover the latter extraction method used no environmental hazardous chemical reagents and was easy to perform.

Effects of CO2 on the resuscitation of Listeria monocytogenes injured by various bactericidal treatments.

To assure the microbiological safety and quality of a food product, a combination of preservation hurdles is often used. Therefore, the effects of carbon dioxide at concentrations of 0, 20, 40 and 60% in modified atmospheres on the resuscitation of Listeria monocytogenes cells injured by mild bactericidal treatments during storage at 7 degrees C were examined. The bactericidal treatments were intense light pulses (ILP), chlorine dioxide (ClO(2)), lactic acid (LA) and heat. The results indicated additional bactericidal effects of CO(2) on cultures treated with LA, ClO(2) and ILP, with additional reductions in viable L. monocytogenes of 0.5-1.0 log cfu/ml. Lag phase duration was significantly different between the different treatments, with non-treated cells having the shortest lag phase, followed by that of heat, intense light pulses, lactic acid and finally ClO(2) treated cells. Maximum growth rate was also estimated and results showed a negative correlation with increasing CO(2) concentrations. A relationship was found between the amount of sub-lethally damaged cells after a mild inactivation treatment and the lag phase duration in the CO(2) environment. Current findings demonstrate the possibility that combining mild decontamination treatments and packaging in a CO(2) enriched environment could reduce the risk of L. monocytogenes infections in food due to an extension of the lag phase.

Shelf-life of minimally processed lettuce and cabbage treated with gaseous chlorine dioxide and cysteine.

Gaseous ClO2 was evaluated for effectiveness in prolonging the shelf-life of minimally processed (MP) lettuce and MP cabbage, previously immersed in a cysteine solution in order to inhibit browning occurring during ClO2 treatment. Each vegetable was shredded, washed, and separated in two portions, one to be treated with ClO2 gas and the other to remain untreated as reference sample. The batch to be treated with ClO2 gas was immersed for 1 min in a 0.5% solution of HCl.L-cysteine monohydrate. Then both batches were spun dried. MP vegetables were decontaminated in a cabinet at 90-91% relative humidity and 22-25 degrees C up to 10 min, including 30 s of ClO2 injection into the cabinet. The ClO2 concentration rose to 1.74 mg/L (MP lettuce) and 1.29 mg/L (MP cabbage). Then samples were stored under modified atmosphere at 7 degrees C for shelf-life studies. Changes in O2 and CO2 headspace concentrations, microbiological quality (aerobic plate count (APC), psychrotrophs, lactic acid bacteria, and yeasts), sensory quality, and pH were followed during storage. The respiration rate of the minimally processed vegetables was significantly increased by the ClO2 gas treatment only in the case of MP cabbage (P<0.05). The gas treatment reduced initially APC and psychrotroph count of MP lettuce and APC, psychrotroph counts, yeast counts and pH of MP cabbage (P<0.05). ClO2 treatment did not cause initially any significant (P<0.05) sensorial alteration, except for a weak off-odour in MP lettuce. Interestingly, no browning was observed after treating, which can be accounted to the use of L-cysteine. Although an initial microbiological reduction was observed due to ClO2 gas treatment, APC and psychrotroph counts reached in the samples treated with ClO2 higher levels than in those non-treated with ClO2 before the third day of the shelf-life study. Untreated and treated samples of MP lettuce were sensorial unacceptable due to bad overall visual quality after 4 days, while treated and untreated MP cabbage remained sensorial acceptable during the 9 days of the study. L-cysteine reduced (P<0.05) the decontamination efficacy of ClO2 when applied to MP cabbage but not in the case of MP lettuce. Gaseous ClO2 failed to prolong the shelf-life of MP lettuce and MP cabbage, the reason for the enhanced growth of microorganisms in decontaminated samples should be investigated. Nonetheless, our results prove that it is possible to inhibit browning caused by ClO2.

Detection of murine norovirus 1 by using plaque assay, transfection assay, and real-time reverse transcription-PCR before and after heat exposure.

The correlation between the detection of murine norovirus 1 RNA by real-time reverse transcription-PCR and the infectivity by plaque assay before and after heat exposure (80 degrees C) was examined. No correlation was found in the current study. Moreover, heat inactivation had a much stronger detrimental effect on virus infectivity than on the integrity of the viral genome.

The effect of inoculum size on the growth of Penicillium expansum in apples.

Penicillium expansum is the most important cause of blue mould rot, a major post-harvest disease of apples worldwide. The objective of this study was to evaluate the effect of the inoculum size on the germination and growth parameters of P. expansum under different storage conditions in apples. Growth of P. expansum was observed in more than 90% of the inoculations, when the inoculum was equal or higher than 2x10(4) spores. The use of a low inoculum level resulted in longer lag phases and a larger variability of the estimated lag phase. This indicates that more replications are necessary to estimate the lag phase of the mould in the specified circumstances. At lower temperature, more inoculum was necessary to reduce the variability of the estimated lag phase, showing that this effect is temperature dependent. Moreover, the effect of the inoculum level on the lag phase is even more pronounced for a slower growing strain. These results imply that the inoculum size influences the estimated growth parameters and should be considered in quantitative risk assessments and for the design of challenge tests and experiments to gather data for predictive growth models.

Influence of storage conditions of apples on growth and patulin production by Penicillium expansum.

Penicillium expansum causes blue mould rot, a serious post-harvest disease of apples, and is the main producer of the mycotoxin patulin. The present study aimed to determine the influence of storage conditions (i.e. temperature and O(2) level) on growth and patulin production by different P. expansum strains on a simulation medium and on apples. Growth was strongly influenced by the temperature, while the used atmosphere (20, 3, and 1% O(2); <1% CO(2)) had no effect. Optimal growth was observed at 25 degrees C for every strain tested. Patulin production was stimulated when the temperature decreased (from 20 to 10 or 4 degrees C), while a further decrease of the temperature to 1 degrees C caused a reduction in patulin production. The temperature at which the stimulation was changed into suppression was strain dependent. Similar results were observed for the O(2) level. A reduction of the O(2) level from 20 to 3% O(2) could stimulate or suppress patulin production depending on the strain, while a clear decrease of the patulin production was observed when the O(2) level was reduced from 3 to 1%. These results show that the induction of limited stress to the fungus, such as lowering the temperature or lowering the O(2) levels stimulates patulin production. However, the combination of different stress conditions (e.g. low temperature and low O(2)) will result in a reduced formation of the toxin. The combination of stress conditions, at which the transition from stimulation to suppression is observed, is strain dependent. Moreover, patulin production is characterized by a high natural variability. The presented results show that the temperature and O(2) level has to be as low as possible during the storage of apples in order to suppress patulin production and to guarantee food safety.

Establishment of procedures provoking sub-lethal injury of Listeria monocytogenes, Campylobacter jejuni and Escherichia coli O157 to serve method performance testing.

In this study procedures provoking sub-lethal injury for three different pathogens are described which may be used in determination of accuracy and robustness of methods, comparison studies and or validation of rapid detection methods. Three common food-borne pathogens were used, Listeria monocytogenes, Campylobacter jejuni and Escherichia coli O157. The pathogens were exposed to heat stress, cold stress, freeze stress, acid stress, oxidative stress and "food" stress. Sub-lethal injury was determined by plating in parallel on selective and non-selective media. The statistical significant differences in enumeration were established. The choice of stress to create sub-lethal injury to cells depended on the fact that the procedure must be easy to handle, repeatable and relevant for stress conditions in foods, but also on the micro-organism itself. Oxidative stress (1000 microM H(2)O(2)) was chosen to impose sub-lethal injury on L. monocytogenes and a specific "food" stress for E. coli O157. For C. jejuni a specific "food" stress as well as the oxidative stress (750 microM H(2)O(2)) were capable of creating a standardized procedure of provoking injury.

Modeling the effect of temperature on the growth rate and lag phase of Penicillium expansum in apples.

The objective of the present study was to develop validated models that describe the effect of storage temperature on the growth rate and lag phase of six Penicillium expansum strains. The growth of the selected strains was therefore studied on Apple Puree Agar Medium (APAM) at 30, 25, 16, 10, 4 and 2 degrees C. Growth rates and lag phases were estimated using linear regression. Several secondary models were evaluated and for the growth rate, a modification of the extended Ratkowsky model was selected. Regarding the lag phase, the Arrhenius-Davey model provided the best adjustment to the observed data. Model validation was performed in two steps. Firstly, the developed models were validated on APAM. The obtained bias factors (Bf) ranged from 0.91 to 1.14 and the accuracy factors (Af) were <1.2 for the validation performed on APAM, indicating that the models were good predictors of the true mean colony growth rate and lag phase. Afterwards, an external validation was carried out in apples. For the growth rate, Bf ranged from 0.64 to 0.81 and Af<1.39, indicating conservative predictions. On the contrary for the lag phase, a clear deviation was observed between predictions and observed values on apples (0.351.6). These results highlight that the use of simulation or synthetic media for the development of predictive models for the lag phase of moulds can lead to inadequate predictions and that a validation on the real food matrix is necessary. Application of the developed models is possible in the framework of Quantitative Risk Assessment to develop control strategies against blue mould rot in apple and enables the inclusion of strain variability. However, possible underestimation of the lag phase should be taken into account.

Variability and uncertainty assessment of patulin exposure for preschool children in Flanders.

The objective of the present study was to evaluate the patulin exposure of children consuming organic, handcrafted or conventional apple juice through a probabilistic approach and to evaluate the effectiveness of several risk management options aiming to reduce the risk for children due to patulin exposure. However, a large part of the data on patulin contamination of apple juice fell under the limit of detection (LOD). Different methods were tested to deal with these so-called left censored data and a uniform distribution with uncertain bounds was selected to handle this censorship. Variability and uncertainty assessment of patulin exposure showed that 0.9% [90% confidence interval (CI): 0.3-1.8%] of the children consuming only organic apple juice exceed the tolerable daily intake (TDI). For consumers of conventional and handcrafted apple juice this was respectively 0.1% [90% CI: 0-0.3%] and 0% [90% CI: 0-0.2%]. Reduction of the patulin contamination in apple juice to concentrations below 25 microg/kg reduced the percentage of the children exceeding the TDI to 0% [90%CI: 0-0.2%] for organic apple juice. Reduction of the apple juice consumption was less effective than a reduction of the patulin concentration in apple juice and is only useful when the patulin concentration of apple juice is below 25 microg/kg.

Shelf-life of minimally processed cabbage treated with neutral electrolysed oxidising water and stored under equilibrium modified atmosphere.

Minimally processed vegetables (MPV) have a short shelf-life. Neutral electrolysed oxidising water (NEW) is a novel decontamination method. The objective of this study was to test the potential of NEW to extend the shelf-life of a MPV, namely shredded cabbage. Samples of shredded cabbage were immersed in NEW containing 40 mg/L of free chlorine or tap water (control) up to 5 min, and then stored under equilibrium modified atmosphere at 4 degrees C and 7 degrees C. Proliferation of aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria and yeasts were studied during the shelf-life. Also pH and sensorial quality of the samples as well as O(2) and CO(2) composition of the headspace of the bags was evaluated. From the microbial groups, only psychrotrophic counts decreased significantly (P<0.05) due to the effect of NEW, but the counts in treated samples and controls were similar after 3 days of storage at 4 degrees C and 7 degrees C. Packaging configurations kept O(2) concentration around 5% and prevented CO(2) accumulation. pH increased from 6.1-6.2 to 6.4 during the shelf-life. No microbial parameter reached unacceptable counts after 14 days at 4 degrees C and 8 days of storage at 7 degrees C. The shelf-life of controls stored at 4 degrees C was limited to 9 days by overall visual quality (OVQ), while samples treated with NEW remained acceptable during the 14 days of the experiment. The shelf-life of controls stored at 7 degrees C was limited to 6 days by OVQ and browning, while that of samples treated with NEW were limited to 9 days by OVQ, browning and dryness. According to these results, a shelf-life extension of at least 5 days and 3 days in samples stored respectively at 4 degrees C and 7 degrees C can be achieved by treating shredded cabbage with NEW. NEW seems to be a promising method to prolong the shelf-life of MPV.

Modeling individual cell lag time distributions for Listeria monocytogenes.

The food industry faces two paradoxical demands: on the one hand, foods need to be microbiologically safe for consumption and on the other hand, consumers want fresh, minimally processed foods. To meet these demands, more insight into the mechanisms of microbial growth is needed, which includes, among others, the microbial lag phase. This is the time needed by bacterial cells to adapt to a new environment (for example, after food product contamination) before starting an exponential growth regime. Since food products are often contaminated with low amounts of pathogenic microorganisms, it is important to know the distribution of these individual cell lag times to make accurate predictions concerning food safety. More precisely, cells with the shortest lag times (i.e., appearing in the left tail of the distribution) are largely decisive for the outgrowth of the population. In this study, an integrated modeling approach is proposed and applied to an existing data set of individual cell lag time measurements of Listeria monocytogenes. In a first step, a logistic modeling approach is applied to predict the fraction of zero-lag cells (which start growing immediately) as a function of temperature, pH, and water activity. For the nonzero-lag cells, the mean and variance of the lag time distribution are modeled with a hyperbolic-type model structure. This mean and variance allow identification of the parameters of a two-parameter Weibull distribution, representing the nonzero-lag cell lag time distribution. The integration of the developed models allows prediction of a global distribution of individual cell lag times for any combination of environmental conditions in the interpolation domain of the original temperature, pH, and water activity settings. The global fitting quality of the model is quantified using several measures indicating that the model gives accurate predictions, erring slightly on the fail-safe side when predicting the shortest lag times.