Development and validation of the Standard method EN ISO 19020 - microbiology of the food chain - Horizontal method for the immunoenzymatic detection of staphylococcal enterotoxins in foodstuffs.

In the frame of the CEN Mandate M/381 from the European Commission to CEN (European Committee for Standardization), a method for the detection of staphylococcal enterotoxins in foodstuffs has been developed, validated and standardized. An extraction procedure based on dialysis concentration followed by an immuno-enzymatic detection has been defined. In addition, performance criteria (minimum values of sensitivity, specificity and level of detection) to be achieved by the commercially available immuno-enzymatic kits that could be used to detect staphylococcal enterotoxins in food matrices, were developed. A 2-stage validation study was conducted: The first stage aimed at selecting the commercial kits to be included in the second stage, which consisted in an interlaboratory study, using eight matrices covering five food categories (ready-to-eat food, meat products, milk products, dessert and fish). Results showed that two detection kits included in the study met the pre-defined performance criteria. The implementation of dialysis concentration step increased significantly the sensitivity of the method. The method developed allowed to achieve the Benchmark Dose lower limit (BMD10) estimated at 6.1 ng. In 2019, finally, the European Commission recognized this standard as the European Union reference method for the detection of staphylococcal enterotoxins in food.

Use of a navigation system in endonasal surgery: Impact on surgical strategy and surgeon satisfaction. A prospective multicenter study.

OBJECTIVES: Surgical navigation systems (SNS) are now widely used in endoscopic endonasal surgery. Benefit, however, has not been fully studied. The objective of this study was to evaluate the impact of an SNS in terms of performance of the surgical procedure and of surgeon satisfaction, in a prospective multicenter study. MATERIALS AND METHODS: A multicenter prospective study included patients undergoing endoscopic endonasal surgery using the electromagnetic DigiPointeur® (DGP) SNS in 16 French hospitals. An observation form, completed by the surgeon immediately at end of procedure, included type of procedure, and any changes in strategy or extent of surgery related to use of the SNS. Surgeon satisfaction was rated on an analog scale, with self-assessment of stress experienced during the procedure. RESULTS: The study included 311 patients operated on by 36 surgeons in 16 French hospitals. Ethmoidectomy was the most frequent procedure (90%); tumor resection was performed in 5.1% of cases. The SNS enabled more extensive surgery in 81% of cases, in particular by identifying and opening additional cells (57% of cases). Mean satisfaction was 8.6/10; surgeons reported decreased surgical stress thanks to the SNS in 95% of cases. CONCLUSION: In this observational study, the use of an SNS increased the extent of surgery in 81% of cases, and had a positive impact on the stress perceived by the surgeon in 95% of cases.

Validation of EN ISO method 15216 - Part 1 - Quantification of hepatitis A virus and norovirus in food matrices.

Hepatitis A virus (HAV) and norovirus are important agents of food-borne human viral illness, with common vehicles including bivalve molluscan shellfish, soft fruit and various vegetables. Outbreaks of viral illness due to contamination of the surfaces of foods, or food preparation surfaces by for example infected food handlers are also common. Virus analysis of food matrices can contribute towards risk management for these hazards and a two-part technical specification for determination of Hepatitis A virus and norovirus in food matrices (ISO/TS 15216:2013) was published jointly by the European Committee for Standardisation and the International Organization for Standardization in 2013. As part of the European Mandate No. M381 to validate 15 standards in the field of food microbiology, an international validation study involving 18 laboratories from 11 countries in Europe was conducted between 2012 and 2014. This study aimed to generate method characteristics including limit of detection, limit of quantification, repeatability and reproducibility for ISO 15216 - Part 1, the method for quantification, in seven food matrices. The organization and results of this study, including observations that led to improvements in the standard method are presented here. After its conclusion, the method characteristics generated were added to the revised international standard, ISO 15216-1:2017, published in March 2017.

A pan-European ring trial to validate an International Standard for detection of Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus in seafoods.

Globally, vibrios represent an important and well-established group of bacterial foodborne pathogens. The European Commission (EC) mandated the Comite de European Normalisation (CEN) to undertake work to provide validation data for 15 methods in microbiology to support EC legislation. As part of this mandated work programme, merging of ISO/TS 21872-1:2007, which specifies a horizontal method for the detection of V. parahaemolyticus and V. cholerae, and ISO/TS 21872-2:2007, a similar horizontal method for the detection of potentially pathogenic vibrios other than V. cholerae and V. parahaemolyticus was proposed. Both parts of ISO/TS 21872 utilized classical culture-based isolation techniques coupled with biochemical confirmation steps. The work also considered simplification of the biochemical confirmation steps. In addition, because of advances in molecular based methods for identification of human pathogenic Vibrio spp. classical and real-time PCR options were also included within the scope of the validation. These considerations formed the basis of a multi-laboratory validation study with the aim of improving the precision of this ISO technical specification and providing a single ISO standard method to enable detection of these important foodborne Vibrio spp.. To achieve this aim, an international validation study involving 13 laboratories from 9 countries in Europe was conducted in 2013. The results of this validation have enabled integration of the two existing technical specifications targeting the detection of the major foodborne Vibrio spp., simplification of the suite of recommended biochemical identification tests and the introduction of molecular procedures that provide both species level identification and discrimination of putatively pathogenic strains of V. parahaemolyticus by the determination of the presence of theromostable direct and direct related haemolysins. The method performance characteristics generated in this have been included in revised international standard, ISO 21872:2017, published in July 2017.

Nonlinear waves in solids with slow dynamics: an internal-variable model.

In heterogeneous solids such as rocks and concrete, the speed of sound diminishes with the strain amplitude of a dynamic loading (softening). This decrease, known as 'slow dynamics', occurs at time scales larger than the period of the forcing. Also, hysteresis is observed in the steady-state response. The phenomenological model by Vakhnenko et al. (2004 Phys. Rev. E 70, 015602. (doi:10.1103/PhysRevE.70.015602)) is based on a variable that describes the softening of the material. However, this model is one dimensional and it is not thermodynamically admissible. In the present article, a three-dimensional model is derived in the framework of the finite-strain theory. An internal variable that describes the softening of the material is introduced, as well as an expression of the specific internal energy. A mechanical constitutive law is deduced from the Clausius-Duhem inequality. Moreover, a family of evolution equations for the internal variable is proposed. Here, an evolution equation with one relaxation time is chosen. By construction, this new model of the continuum is thermodynamically admissible and dissipative (inelastic). In the case of small uniaxial deformations, it is shown analytically that the model reproduces qualitatively the main features of real experiments.

[Invasive aspergillosis of sphenoidal sinus in a patient in Djibouti, revealed by palsy of cranial nerves: a case report]. / Aspergillose invasive du sinus sphénoïdal révélée par une paralysie de paires crâniennes : à propos d'un cas pris en charge à Djibouti.

The authors report a case of invasive aspergillosis of a sphenoid sinus mucocele revealed in a patient with diabetes in Djibouti by homolateral palsy of the 3rd, 4th, 5th and 6th nerves. This rare condition occurs preferentially in immunodeficient subjects. Because of its clinical polymorphism, its diagnosis is difficult and is often not made until complications develop. Endonasal surgery with anatomopathological and mycological examination is both a diagnostic and therapeutic procedure. It must be performed early, to avoid functional or even life-threatening complications.

Intra-laboratory validation of the Ridascreen® SET Total kit for detecting staphylococcal enterotoxins SEA to SEE in cheese.

AIM: To determine the performance of the Ridascreen® SET Total kit, after sample extraction and concentration by dialysis, with regard to its use in official controls for staphylococcal enterotoxins under European Regulation (EC) No. 2073/2005 modified. This study was conducted on naturally contaminated cheese samples and compared with the results of the previously validated Vidas® SET2 kit. METHODS AND RESULTS: The effectiveness of the Ridascreen® SET Total kit on naturally contaminated cheeses was compared to that of the Vidas® SET2 kit by applying the EN ISO 16140 standard. Sensitivity and specificity were also compared using spiked buffer solutions and cheese samples with SEA to SEE toxins. CONCLUSIONS: This study showed that the Ridascreen® SET Total kit is as effective as the Vidas® SET2 kit. SIGNIFICANCE AND IMPACT OF THE STUDY: The Ridascreen® SET Total kit was found to specifically detect SEA to SEE in cheeses. The Ridascreen® SET Total can therefore be used to check the staphylococcal enterotoxin content and ensure consumer protection.

Detection, isolation and characterization of Shiga toxin-producing Escherichia coli in retail-minced beef using PCR-based techniques, immunoassays and colony hybridization.

AIMS: To provide information on detection of Shiga toxin-producing Escherichia coli (STEC) in retail-minced beef using an approach combining (i) PCR-based techniques and automated immunoassay for stx screening and detection of the five major serogroups associated with human infection, and (ii) immunomagnetic separation (IMS) and colony hybridization assays for bacterial strain isolation. METHODS AND RESULTS: Twenty-seven out of 164 minced beef samples were stx-positive by PCR-ELISA, nine of which were also positive by real-time PCR for at least one marker of the five main serogroups tested (O26, O103, O111, O145 and O157). Two E. coli O103 stx-negative strains were isolated from two out of 10 IMS and nine STEC strains that did not belong to the five main serogroups were isolated by colony hybridization. CONCLUSIONS: PCR techniques are applicable for rapid screening of samples containing both an stx gene and an O-group marker of the five main pathogenic STEC serogroups. Isolation of STEC strains belonging to the main non-O157 serogroups remains difficult. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents an evaluation of a multi-faceted approach for the detection of the most frequently reported human pathogenic STEC serogroups. The advantages and limits of this strategy are presented.

Intralaboratory validation according to the EN ISO 16 140 Standard of the Vidas SET2 detection kit for use in official controls of staphylococcal enterotoxins in milk products.

AIM: Immunological tools used to detect staphylococcal enterotoxins (SEs) in foods are numerous. The aim of this study was to evaluate, on naturally contaminated milk product samples, the performance of the Vidas SET2, in comparison to the Transia plate SET. METHODS AND RESULTS: The Vidas SET2 was compared with the Transia plate SET on supernatants of Staphylococcus aureus isolates and on naturally contaminated milk products. It is noteworthy that when using IgG rabbit treatment, both kits can be considered as equivalent to detect enterotoxins in naturally contaminated milk products. CONCLUSIONS: This study demonstrated that the Vidas SET2 performance is similar to that of Transia plate SET kit, when a rabbit IgG treatment step is used before detection step. This additional treatment significantly decreased, from 42% to 8%, the rate of positive deviations observed using the Transia plate SET detection kit. SIGNIFICANCE AND IMPACT OF THE STUDY: The Vidas SET2 was clearly found as more specific, when no preliminary rabbit IgG treatment was used, and which results in a better workflow when a large number of samples have to be analysed within a few days. Considering the results obtained, the Vidas SET2 detection kit can be used to assess the safety of milk products for SEs.

Validation of EN ISO standard methods 6888 Part 1 and Part 2: 1999--enumeration of coagulase-positive staphylococci in foods.

The methods of European and International Organisations for Standardization for the enumeration of coagulase-positive staphylococci (CPS, Staphylococcus aureus and other species) described in EN ISO 6888 Part 1 and Part 2: 1999 were validated by order of the European Commission (Standards, Measurement and Testing Fourth Framework Programme Project SMT4-CT96-2098). EN ISO 6888-1 prescribes the use of Baird-Parker (BP) agar whereas EN ISO 6888-2 prescribes the use of Rabbit Plasma Fibrinogen Agar (RPFA). The objective was to determine the precision of each method in terms of repeatability (r) and reproducibility (R) using three different food types inoculated with various levels of S. aureus and a typical background flora. The results are intended for publication in the associated standards. Cheese, meat and dried egg powder were examined by 24 laboratories from 16 countries in Europe. Each participant received eight test materials per food type: blind duplicates at four inoculum levels (0, 10(3), 10(4) to 10(5), 10(5) to 10(6) cfu/g). In addition, two reference materials (RM) (capsules containing milk powder inoculated with S. aureus) were included in the study. All test materials were subjected to stringent homogeneity and stability testing before being used in the collaborative trial. Two statistical methods were used to calculate the precision parameters. Draft EN ISO 16140: 2000 method appeared more appropriate to the case of microbiological data than ISO 5725-2: 1994 method and was retained to calculate the precision data. Concerning EN ISO 6888-1, overall values for repeatability (r) when used with food test materials was r=log(10) 0.28 (expressed as an absolute difference between log(10)-transformed test results). For the reference materials, r=log(10) 0.19. Overall values for reproducibility (R) when used with food test materials were R=log(10) 0.43. For the reference materials, R=log(10) 0.39. Concerning EN ISO 6888-2, overall values for repeatability (r) when used with food test materials were r=log(10) 0.22. For the reference materials, r=log(10) 0.17. Overall values for reproducibility (R) when used with food test materials were R=log(10) 0.33. For the reference materials, R=log(10) 0.31. These results were presented to the ISO technical committee and to the Comité Européen de Normalisation (CEN). Both committees agreed to incorporate the precision data obtained with food materials as two amendments to EN ISO 6888-1 and -2, and to give an equal status to each part of the standard.

Analysing collaborative trials for qualitative microbiological methods: accordance and concordance.

In qualitative (detection) food microbiology, the usual measures of repeatability and reproducibility are inapplicable. For such studies, we introduce two new measures: accordance for within laboratory agreement and concordance for between laboratory agreement, and discuss their properties. These measures are based on the probability of finding the same test results for identical test materials within and between laboratories, respectively. The concordance odds ratio is introduced to present their relationship. A method to test whether accordance differs from concordance is discussed.

Proficiency testing for the evaluation of the ability of European Union-National Reference laboratories to determine aflatoxin M1 in milk at levels corresponding to the new European Union legislation.

In 1992, the European Union set up a network of National Reference Laboratories and charged the Community Reference Laboratory with the responsibility to design a proficiency testing scheme for assessing the analytical ability of laboratories involved in the official control of aflatoxin M1 in milk. Since 1996, two exercises of proficiency testing have been performed on samples of milk powder and liquid milk at various levels of aflatoxin M1 contents. The trials were conducted according to ISO Guide 43, in particular for the homogeneity testing of sample batches and for the calculation of laboratory z-scores. The National Reference Laboratories officially designated by their governments participated in this programme. Samples were naturally-contaminated milk obtained by feeding cows with aflatoxin B1-contaminated feed. The levels of aflatoxin M1 in the samples ranged from 0.2 to 0.7 microg/kg in milk powder and from 0.05 to 0.07 microg/l in liquid milk. These levels were chosen as being close to the European Union-regulated limit of 0.05 microg of aflatoxin M1 per litre. The results produced by laboratories were compiled and statistically analysed to detect any outlying results and to calculate the individual z-scores. Except for one laboratory in each exercise, all laboratories exhibited acceptable or questionable z-scores. The interlaboratory relative standard deviation for reproducibility (RSDR) obtained for both 1996 and 1998 exercises were in the range 15.7-30.3%. Compared with other published studies, this indicates a very good precision for the performance of this laboratory network in the analysis of traces of aflatoxin M1 in milk.

Validation of ISO method 11290 part 1--detection of Listeria monocytogenes in foods.

The European and International Standard method for the detection of Listeria monocytogenes, described in EN ISO 11290 Part 1: 1997 (International Organisation for Standardisation, Geneva) was validated by order of the European Commission (Standards, Measurement and Testing Fourth Framework Programme Project SMT4-CT96-2098). Nineteen laboratories in 14 countries in Europe participated in a collaborative trial to determine the performance characteristics of the method, which are intended for publication in the corresponding standard. An additional objective of this project was to devise a new series of parameters to indicate the 'precision' of microbiological qualitative methods. The method was challenged with three food types, namely fresh cheese, minced beef and dried egg powder and a reference material. Inoculation levels ranged from 5 to 100 cfu/25 g. Each participant examined five replicates of each food type at three inoculum levels and five reference materials. Both PALCAM and Oxford media were assessed. All test materials were subjected to stringent homogeneity and stability testing before being used in the collaborative trial. The results demonstrated that the method prescribed in EN ISO 11290-1 had an overall sensitivity of 85.6% and a specificity of 97.4%. L. monocytogenes was detected in most cases after primary enrichment, although secondary enrichment often yielded further positives. However, a significant number of false-negative results were obtained with all food types when large numbers of L. innocua were present in the test materials. L. innocua tended to dominate L. monocytogenes during the selective enrichment stages and thus masked small numbers of colonies of L. monocytogenes on the isolation media. There was no evidence from this collaborative study to demonstrate a significant difference in performance between Oxford and PALCAM media. Due to the problem of false-negative results with this method as highlighted in this trial, recommendations have been made to ISO to launch a revision of the standard to improve the detection of low numbers of L. monocytogenes in foods. New statistical methods devised to advance the measurement of the performance of qualitative microbiological methods are also described.

Validation of ISO method 11290 part 2. Enumeration of Listeria monocytogenes in foods.

The European and International Standard method for the enumeration of Listeria monocytogenes, described in EN ISO 11290 Part 2: 1998 [EN ISO 11290-2 Microbiology of Food and Animal Feedingstuffs-Horizontal Method for the Detection and Enumeration of L. monocytogenes: Part 2. Enumeration; International Organisation for Standardisation, Geneva.] was validated by order of the European Commission (Standards, Measurement and Testing Fourth Framework Programme Project SMT4-CT96-2098). The objective was to determine the precision of the method in terms of repeatability (r) and reproducibility (R) using three different food types inoculated with various levels of L. monocytogenes and a typical background flora. The results are intended for publication in the associated standards. Cheese, meat, dried egg powder and reference materials were examined by 21 laboratories in 16 countries in Europe. Each participant received eight test materials per food type: blind duplicates at four inoculum levels (0, 10(2), 10(3), 10(4) cfu/g). In addition, two reference materials containing L. monocytogenes were included in the study. All test materials were subjected to stringent homogeneity and stability testing before being used in the collaborative trial. Participants were required to use only PALCAM agar for enumeration of L. monocytogenes, as prescribed by the reference method. Statistical analyses has been performed using a newly introduced approach for food microbiology (draft standard prEN ISO 16140 [prEN ISO 16140 Microbiology of Food and Animal Feedingstuffs-Protocol for the Validation of Alternative Methods, International Organisation for Standardisation, Geneva.], the precision data being calculated using robust estimates. Overall values for repeatability (r) of EN ISO 11290-2 when used with food test materials were r = log10 0.58 (expressed as an absolute difference between log10-transformed test results) or r = 3.8 (expressed as an absolute ratio between test results on the normal scale). For the reference materials (capsules containing approximately 5000 cfu), r = log10 0.34 (expressed as an absolute difference between log10-transformed test results) or r = 2.2 (expressed as an absolute ratio between test results on the normal scale). Overall values for reproducibility (R) of EN ISO 11290-2 when used with food test materials were R = log10 0.81 (expressed as a difference between log10-transformed test results) or R = 6.5 (expressed as an absolute ratio between test results on the normal scale). For the reference materials, R = log10 0.51 (expressed as a difference between log10-transformed test results) or R = 3.2 (expressed as an absolute ratio between test results on the normal scale). Further studies have been initiated by ISO TC34/SC9 to try to enhance the isolation of L. monocytogenes from foods and improve the confirmation procedures.

[The deviated nose. Classification and treatment. Apropos of 100 cases]. / Les nez déviés. Classification et traitement. A propos de 100 cas.

We present a series of 100 deviated noses treated over 5-year period. A classification into four groups was proposed and used to determine preoperative strategy according to the type of deformation. The main corrective methods were lateral cartilage grafts for C-shaped noses and removal and reinstallation of the nasal cartilage for S-shaped nose and "lay down" noses. The best results were obtained for trauma-induced deformations occurring after puberty. Lay-down nose were more difficult to treat than C- and S-shaped noses. Good results can be expected in 80% of the cases. Good nasal flow was obtained in 90% of the patients and secondary surgery was successful in the other 10%.

[Evaluation of transcutaneous electrostimulation in the management of post-tonsillectomy pain in adults]. / Evaluation de l'électrostimulation transcutanée dans la prise en charge des douleurs post-amygdalectomie chez l'adulte.

Transcutaneous electrical nerve stimulation (TENS), has been known for many years, especially in neurosurgery for the treatment of chronic pain syndromes. The authors report the results of the use of this technique in 45 adults feeling acute pain after tonsillectomy. Spontaneous pain and odynophagia were both studied. TENS was effective in 40 out of 45 patients, with full control or significant decrease of the pain. This harmless treatment appears to be attractive and needs larger studies.