Lyme snap: A feasibility study of on-line declarations of erythema migrans in a rural area of France.

The incidence of Lyme borreliosis remains a matter of debate, but it can be estimated using the incidence of erythema migrans (EM), which is pathognomonic of the first phase. The aim of this prospective pilot study was to assess the feasibility of the on-line declaration of EM in rural areas where the incidence of Lyme borreliosis was previously estimated at 85 per 100,000 inhabitants per year. The study was limited to a rural area (Les Combrailles, Auvergne) of approximately 52,800 inhabitants and was preceded by an information campaign for the inhabitants and the healthcare professionals. Patients who sent a photo of the suspected EM by email or MMS message between April 2017 and April 2018 and who accepted to answer a questionnaire were included in the study. Two physicians then evaluated the quality of the photographs and the probability of EM. In parallel, the number of EM seen by physicians and pharmacists in the area over the given period was recorded. Out of the 113 emails and MMS messages received, 73 people were outside of the trial area or period and 9 did not complete the questionnaire. The photos of the remaining 31 people were analysed. The median age was 51.5 years old ([38-58] IQR) and 18 (58%) were women. Seven people (25%) stated that they did not have a smartphone and in 9 cases (29%) the photo was sent by a third party. The quality of the photos was considered very good in 22 (71%) cases, good in 7 (23%) cases, and average in 2 (6%) cases. The probability of EM was determined to be strong or possible in 12 (38%) cases, i.e. an estimated incidence of 22.7 per 100,000 inhabitants. Over the study period, 40 physicians and 20 pharmacists were contacted on a monthly basis. A median of 5 physicians [3;7] and 4 pharmacists [3 ;7] answered each month for a total of 18 and 36 declared EM respectively. The EM (strong probability/possible) collected by on-line declaration and those declared by healthcare professionals were all sent between April and October 2017. The total time spent on the information campaign and collection has been estimated at 265 h (divided between 10 people) for an overall cost of 10,669 Euros. The incidence of EM recorded by on-line self-declaration in our study seems to be lower than in previous studies, the under-reporting was probably linked to the low use of new technologies in the rural areas. Increasing the human resources and finances appears difficult to achieve in practice over a longer time period but the development of an application for the automatic recognition of EM could be one method for a more exhaustive collection in the long term and at lower cost.

Modelling the behaviour of Listeria monocytogenes in ground pork as a function of pH, water activity, nature and concentration of organic acid salts.

AIMS: to study and model the effect of sodium acetate, sodium lactate, potassium sorbate and combination of acid salts on the behaviour of Listeria monocytogenes in ground pork. METHODS AND RESULTS: Water activity (a(w)), pH and concentration of acid salt of the meat were adjusted. The behaviour of inoculated L. monocytogenes was studied and modelled according to physicochemical parameters values. Whatever the acid salt concentration used, we observed an inhibition of the growth of L. monocytogenes at pH 5.6 and a(w) 0.95. At pH 6.2 and a(w) 0.97, addition of 402 mmol l(-1) of sodium lactate or 60 mmol l(-1) of potassium sorbate was required to observe a slower growth. CONCLUSIONS: The inhibitory effect of acid salts was a function of pH, a(w), as well as of the nature and concentration of acid salts added. When one acid salt was added, the Augustin's model (Augustin et al. 2005) yielded generally correct predictions of either the survival or growth of L. monocytogenes. SIGNIFICANCE AND IMPACT OF THE STUDY: The suggested model can be used for risk assessment concerning L. monocytogenes in pork products.

Microbial ecosystems of traditional fermented meat products: The importance of indigenous starters.

This paper reviews the diversity of microbiota, both in the environment and in traditional fermented European sausages. The environments of processing units were colonised at variable levels by resident spoilage and technological microbiota, with sporadic contamination by pathogenic microbiota. Several critical points were identified such as the machines, the tables and the knives - knowledge crucial for the improvement of cleaning and disinfecting practices. Traditionally fermented sausages generally did not present a sanitary risk. The great diversity of lactic acid bacteria and staphylococci was linked to manufacturing practices. Development of indigenous starters is very promising because it enables sausages to be produced with both high sanitary and sensory qualities. Our increasing knowledge of the genomes of technological bacteria will allow a better understanding of their physiology in sausages.

Traditional dry fermented sausages produced in small-scale processing units in Mediterranean countries and Slovakia. 1: Microbial ecosystems of processing environments.

Microbial ecosystems were surveyed in 314 environmental samples from 54 Southern and Eastern European small-scale processing units (PUs) manufacturing traditional dry fermented sausages. The residual microflora contaminating the surfaces and the equipment were analysed after cleaning and disinfection procedures. All the PU environments were colonised at various levels by spoilage and technological microflora with excessive contamination levels in some of the PUs. Sporadic contamination by pathogenic microflora was recorded. Salmonella and Listeria monocytogenes were detected in 4.8% and 6.7% of the samples, respectively, and Staphylococcus aureus was enumerated in 6.1% of the samples. Several critical points were identified, such as the machines for S. aureus and the tables and the knives for L. monocytogenes; this knowledge is crucial for the improvement of hygiene control systems in small and traditional meat processing industries. The variability of the residual contamination emphasized the different cleaning, disinfecting and manufacturing practices routinely followed by these small-scale processing units.

Diversity of microorganisms in the environment and dry fermented sausages of small traditional French processing units.

Naturally fermented sausages produced in nine traditional French processing units and their environmental surfaces were characterised by microbial and physico-chemical analyses. Salmonella and Staphylococcus aureus were not detected in the environment whereas Listeria monocytogenes was detected in four samples. Staphylococcus/Kocuria, lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas, yeasts/moulds and enterococci contaminated the surfaces of two processing units, indicating insufficient cleaning and disinfection procedures. The final sausages did not present any health risk in seven of the processing units. In two of the processing units, the final sausages were contaminated with S. aureus and L. monocytogenes, respectively, at levels exceeding the maximum tolerable limit. Staphylococcus/Kocuria and LAB grew well in the products. Biogenic amines were found in the majority of the final products. Their occurrence was associated with high numbers of lactic acid bacteria and enterococci. The study outlined the processing and microbial diversities of French naturally fermented sausages.

Combined physico-chemical and water transfer modelling to predict bacterial growth during food processes.

The quality and safety of food products depend on the microorganisms, the food characteristics and the process. The prediction of conditions that prevent growth in complex situations due to the characteristics of the process and of the food cannot be obtained by predictive models of bacterial growth only. Thus, a combined modelling approach was developed by integrating three models, which were selected in a first step: (1) a bacterial model that predicts the bacterial growth from the physico-chemical properties of the media; (2) a water transfer model that predicts the effects of the drying process variables on the medium characteristics; and (3) a thermodynamic model that predicts the water activity aw and the pH of the media from its composition. A second step consisted in separately validating each selected model in which all of the physical, chemical or biological parameters appearing in the equations were previously measured. The third step combined the three knowledge models. The global model was validated on the basis of experimental results concerning the growth of Listeria innocua on the surface of a gelatine gel, the surface of which was submitted to a drying process (changes in relative humidity and air velocity). It was shown that bacterial growth models had to be modified: a specific model was set up to predict the maximum growth rate and another for the lag. Additionally, growth models set up in broth could not be applied in gelatine, leading to the development of a specific growth model on a solid surface. The thermodynamic model accurately predicted the pH and aw of bacterial broth in which high concentrations of solutes were added, and those of the solid media, the gelatine. The water transfer model was applied on gelatine data to predict the evolution of its surface aw during the drying process. The three models-bacterial, water transfer and thermodynamic, separately validated-were combined according to an integrated modelling strategy. The water transfer model coupled with the thermodynamic model predicted the aw on the gel surface. The predicted surface aw explained why growth inhibition was observed. Indeed, growth stopped at a predicted surface aw <0.94, corresponding to L. innocua minimum aw during the drying process. The global model satisfactorily predicted L. innocua growth on the surface of the gel. This study proves the validity of the approach and shows that the combination of the water transfer and thermodynamic models compensates for the lack of aw measurement techniques.

Effect of a(w), controlled by the addition of solutes or by water content, on the growth of Listeria innocua in broth and in a gelatine model.

The effect of a(w) on the growth of Listeria innocua was investigated in broth and on the surface of a gelatine food model. In broth, a(w) was controlled from 0.91 to 0.99 by the addition of solutes such as NaCl, KCl, glucose, sucrose and glycerol. In the gelatine food model, a(w) was controlled by removal of water. In the a(w) range, 0.92-0.99, the generation times observed in broth in the presence of NaCl, KCl, sucrose and glucose were similar but were longer than those in glycerol. For lag times, the inhibition of L. innocua growth followed the order: NaCl = KCl = sucrose>glucose>glycerol. When comparing growth at a(w) 0.95 for the three media--broth + NaCl, gelatine gel (a(w) controlled by removal of water) and gelatine gel with NaCl (gel + NaCl, a(w) controlled by NaCl)--the shortest generation time was observed in broth + NaCl, followed by gel + NaCl and, finally, on gel with a larger gap between the last two. The generation time on gel was five times greater than the generation time in broth + NaCl and 2.5 times greater on gel + NaCl. It was concluded that not only the structure of the media (solid or liquid) had an effect on Listeria inhibition but also and mainly the way the a(w) was adjusted. Removal of water was more stressful to Listeria than the addition of NaCl.

Application of polynomial models to predict growth of mixed cultures of Pseudomonas spp. and Listeria in meat.

Three models for one rapid and one slow growing strain of Pseudomonas fragi and one slow growing strain of P. fluorescens were developed in a meat broth; they were designed to take account of variations in growth and to provide a growth response interval. These models, and another for Listeria monocytogenes (Lm14 model), were used to predict the growth of spoilage Pseudomonas spp. and pathogenic Listeria in meat products. The Pseudomonas and Listeria models provided satisfactory predictions concerning inoculated strains grown in decontaminated beef meat. It was also possible to use the Pseudomonas models to predict the growth of the natural flora (mainly Pseudomonas spp.) of refrigerated meat stored under aerobic conditions. In experiments with mixed populations, three situations were observed: (1) in decontaminated meat, L. monocytogenes inoculated alone grew well at 6 degrees C, and this result was correctly predicted by the model; (2) in decontaminated meat inoculated with Listeria and Pseudomonas strains, L. innocua grew well and was not affected by the presence of Pseudomonas, and the growth of both organisms was correctly predicted by the models; (3) in naturally contaminated meat inoculated with Listeria, the strain did not grow until Pseudomonas had reached the stationary phase. The models satisfactorily predicted the growth of Pseudomonas spp. but not that of Listeria. In conclusion, the Lm14 model cannot be used for refrigerated meat stored aerobically as the results suggest a 'fail-safe' level which may be too high: meat had already reached a spoilage state even though no increase in the level of Listeria was observed. The Pseudomonas models accurately predicted the growth of naturally occurring Pseudomonas spp.

Effects of pH or a(w) stress on growth of Listeria monocytogenes.

The growth of three strains of Listeria monocytogenes at 20 degrees C in a meat broth of different pH or water activity was investigated. At inoculation or at the beginning of the exponential phase, cells were exposed to stress by the addition of NaOH or NH4+, acetic acid, NaCl or KCl, in order to reach a pH of either 9.0 or 5.6, or an a(w) of 0.950 or 0.965, respectively. The effects of the exposure to stress on the generation and lag times of each strain were analysed by turbidity measurements for cultures in micro-titer plates. Results were confirmed by conducting the same experiments in a fermentor, except for the maximal population reached. The three strains showed similar behaviour. Cells were able to overcome the alkaline stress rapidly whereas acid and osmotic shocks induced important changes of the growth parameters. Cells exposed to acid or osmotic conditions from the time of inoculation were less affected than cells exposed at the beginning of the mid-exponential phase.

Growth of Pseudomonas fluorescens and Pseudomonas fragi in a meat medium as affected by pH (5.8-7.0), water activity (0.97-1.00) and temperature (7-25 degrees C).

A total of 59 strains of Pseudomonas, isolated from meat products, were grown in micro-titer plates in a meat medium over a range of pH (5.8-7.0), alpha w (0.97-1.00) and temperature (7-25 degrees C). Growths were performed in a meat broth with an automated turbidimeter (Bioscreen C, Labsystem, France). The growth curves obtained in this study did not have sigmoidal shapes making it impossible to calculate growth parameters using the Gompertz equation. The medium was weakly oxygenated in the micro-titer plates and reached 0%-dissolved oxygen at the beginning of the exponential phase. Strains were separated into two groups: P. fragi and P. fluorescens. Strains of P. fragi had shorter lag times than those of P. fluorescens. The impact of such results is interesting in that these could assist to explain the succession of flora that is observed during the processing of meat: P. fluorescens is the dominant bacteria among Pseudomonas spp. at the beginning of a slaughter line and P. fragi becomes dominant during the chilling process.