Search

International audience; Ochratoxin A (OTA) in coffee is associated with serious health problems and significant economic loss. The state of Chiapas is the top coffee producer in Mexico, accounting for 41.3% of the national production, and the second largest organic coffee-producing area worldwide. Due to the lack of information about the OTA content in Chiapas coffee, 100 coffee samples from Chiapas were collected and classified according to their variety, type (roasted or nonroasted), processing and cultivation, in the 2017/2018 cycle. The average OTA concentration in 97 of the analyzed samples was 0.41 μg/kg. OTA was not detected in 52% of the samples; in 45% of the samples, the concentration ranged between 0.05 and 3.4 μg/kg, below the limit of European regulations (

International audience; Victoria Pure Blue BO is a dye that bears some therapeutic activity and that can be retrieved in effluent or may be used in aquaculture as a prohibited drug. In this study, the metabolism and tissue distribution during uptake and depuration of VPBO were investigated in order to propose a residue marker of illegal treatment in fish. The dye was administered to rainbow trout (oncorhynchus mykiss) for one day by water bath at a dose of 0.1 mg.L(-1). The concentrations of VPBO in all tissues increased rapidly during the treatment period, reaching a C(max) of 567 ± 301 μg.L(-1) in plasma and 1846 μg kg(-1) ±517 for liver after 2 h. After placing the rainbow trout in a clean water bath for a 64 day-period of depuration, the concentrations in the tissues and plasma decreased to reach comparable levels for muscle and for skin after 33 days. The concentrations measured were still above the LOQ at 2.26 ± 0.48 μg kg(-1) for muscle and 2.85 ± 1.99 μg kg(-1) for skin at the end of the depuration period. The results indicated the existence of 14 phase I metabolites and one glucuronide conjugated metabolite. Non-compartmental analysis was applied to assess the pharmacokinetic parameters. The half-life in edible muscle of the main metabolite detected, deethyl-leuco-VPBO, was found to be 22.5 days compared to a half-life of 19.7 days for the parent VPBO. This study provides new information to predict a VPBO drug treatment of aquacultured species via a proposed new residue marker.

International audience; The administration of nitrofurans to livestock to treat or prevent animal diseases has been banned in the EU for the production of food of animal origin. The corresponding marker residues are tissue-related metabolites AMOZ, AHD, SEM, and AOZ. The MRPL (minimum required performance limit)/RPA (Reference point for action) was set at 1 µg kg(-1) in the EU. Thus, all the laboratories involved in the control of nitrofuran metabolites must detect at least at this analytical limit of performance. The objectives of the work reported here were to evaluate the performance of ELISA kits from two different manufacturers (R-Biopharm, Germany; Europroxima, the Netherlands) for the individual screening of the four nitrofuran metabolites (AOZ, AMOZ; AHD; and SEM) in aquaculture products (fish, shrimps), and then to validate the kits according to the European Decision EC/2002/657 and to the European guideline for the validation of screening methods. The false positive rates were below 9 % for the kits from both manufacturers. The detection capabilities CCβ determined were all below the current RPA (1 µg/kg). However, regarding the updated RPA at 0.5 µg/kg that shall apply in 2022, the AMOZ and SEM kits from R-Biopharm and the SEM kit from Europroxima will not be able to reach it.

Dyes from the triarylmethane family are prohibited in aquaculture because of their toxicity. Despite this, they are still used in aquaculture due to their antiseptic and antifungal properties, and to their low costs and availability as chemicals in the industry. In order to protect consumers, European regulations impose strict controls on residues of prohibited substances in food of animal origin. In France, for dyes with pharmacological activity, this control is targeted on the presence of residues of malachite green, crystal violet and brilliant green in aquaculture products, including their marker residues in the form of metabolized leuco-bases. To anticipate the future of dye monitoring due to possible new practices in fish farming, this thesis explored different approaches based on the analysis of the fish metabolome by liquid chromatography coupled with High Resolution mass spectrometry and in vitro or in vivo methodologies. The results of this project provide data i) on the behaviour and fate of dyes in fish and ii) on their effects, with a view to proposing markers of treatments extracted from the endometabolome and / or the xenometabolome. We observed a biological disturbance in the production of bile acids after treatments with malachite green and with victoria pure blue bo (VPBO). Moreover, a direct metabolite resulting from the treatment of trout with VPBO, ie. deethyl-leuco-VPBO, has been highlighted as an appropriate marker residue in fish muscle and skin. Finally, an analytical method extended to several other families of dyes has been developed by means of liquid chromatography coupled with tandem mass spectrometry, and including the new marker residues of treatment., Les colorants de la famille des triarylméthanes sont interdits en aquaculture à cause de leur toxicité. Malgré cela, ils sont toujours utilisés en aquaculture du fait de leurs propriétés antiseptiques et antifongiques, de leurs faibles coûts et de leur disponibilité en tant que produits chimiques pour certaines industries. Afin de protéger les consommateurs, la réglementation européenne impose des contrôles stricts des résidus de substances interdites dans les denrées d’origine animale. En France, pour les colorants à activité pharmacologique, ce contrôle est ciblé sur la présence de résidus de vert de malachite, de cristal violet et de vert brillant dans les produits d’aquaculture, incluant leurs résidus marqueurs métabolisés sous forme de leucobases.

International audience; Aluminum (Al) can be taken up from food, packaging, or the environment and thus reaches the human gastrointestinal tract. Its toxic potential after oral uptake is still discussed. The fate of different solid and ionic Al species during the passage through the digestive tract is the focus of this research, as well as the cellular effects caused by these different Al species. The present study combines the physicochemical processing of three recently studied Al species (metallic Al0, mineral Al2O3, and soluble AlCl3) in artificial digestion fluids with in vitro cell systems for the human intestinal barrier. Inductively coupled plasma mass spectrometry (ICP-MS) and small-angle X-ray scattering (SAXS) methods were used to characterize the Al species in the artificial digestion fluids and in cell culture medium for proliferating and differentiated intestinal Caco-2 cells. Cytotoxicity testing and cellular impedance measurements were applied to address the effects of digested Al species on cell viability and cell proliferation. Microarray-based transcriptome analyses and quantitative real-time PCR were conducted to obtain a deeper insight into cellular mechanisms of action and generated indications for cellular oxidative stress and an influence on xenobiotic metabolism, connected with alterations in associated signaling pathways. These cellular responses, which were predominantly caused by formerly ionic Al species and only at very high concentrations, were not impacted by artificial digestion. A two-directional conversion of Al between ionic species and solid particles occurred throughout all segments of the gastrointestinal tract, as evidenced by the presence of nanoscaled particles. Nevertheless, this presence did not increase the toxicity of the respective Al species.

International audience; The Infiniplex for milk(R) (IPM) kit is a quick method for the simultaneous and qualitative detection of more than 100 molecules including antibiotic residues, mycotoxins, anti-inflammatories and antiparasitic drugs into a single test that does not require milk treatment. The IPM(R) kit was validated according to the European decision EC/2002/657 and according to the European guideline for the validation of screening methods (2010). Our validation was focused only on antibiotic residues. The washing step was identified as the most critical step of the assay. Insufficient washes could cause a significant background noise that prevents imaging. Positive controls have to be freshly prepared each day (insufficient stability). The method was specific with a low false-positive rate of 1.7% on 5 discrete test regions (DTR) ((beta-lactams, lincomycin, virginiamycin, quinolones and sulphonamides)) and a false-positive rate of 0% on the 26 other DTR. During our validation, the 42 determined detection capabilities CCbeta for 12 antibiotic families (aminoglycosides, cephalosporins, lincosamides, macrolides, miscellaneous antibiotics, penicillins, phenolated polymixins, polypeptide antibiotics, quinolones, sulphonamides, tetracyclines) were at between once and twice the decision levels stated by the manufacturer. Forty CCbeta determined were lower than the respective regulatory limits (i.e. MRL, RC, MRPL) in milk, except for tilmicosin (1.5 times the MRL) and neospiramycin (>1.25 times the MRL). The estimated CCbeta of thiamphenicol, cloxacillin, danofloxacin, sulphathiazol, ceftiofur and sulphamonomethoxine were lower than or at the MRL. However, it was difficult to approach an accurate CCbeta with only qualitative results. It is impossible to know whether or not we were close to the cut-off value. The software could be improved by differentiating between low-positive and high-positive results. The results of our participation in three qualitative proficiency tests in 2016 and 2017 for the detection of quinolones, tetracyclines and sulphonamides in cows' milk were very satisfactory.

International audience; Colistin is a polypeptide antibiotic mainly used in porcine and poultry to treat gastrointestinal infections. It has been included by the World Health Organisation (WHO) in the list of critically important human antibiotics of high priority for antimicrobial resistance since 2017. Therefore, it is necessary to develop specific and sensitive screening methods for this molecule. Screening for colistin with immunoassays is an interesting alternative to LC-MS/MS screening methods. The performance of three commercially available ELISA kits was evaluated in poultry and porcine muscles for the detection of colistin in regards to its European maximum residue limit (MRL) (150 µg/kg). The applicability of the three ELISA kits to the detection of colistin at or below the MRL in porcine and poultry muscles was demonstrated. The detection capabilities (CCβ) of two kits were or lower than or equal to the MRL (150 µg/kg). The lowest detection capability (30 µg/kg) was achieved with the third ELISA kit. The specificity of the three kits was very satisfactory (false positive rates 0%). The three kits are very specific for the detection of colistin (colistin A and B) and polymyxin B.

International audience; Food additive E551 consists of synthetic amorphous silica (SAS), comprising agglomerates and aggregates of primary particles in the nanorange (

In vitro and in vivo studies have shown that phycotoxins can impact intestinal epithelial cells and can cross the intestinal barrier to some extent. Therefore, phycotoxins can reach cells underlying the epithelium, such as enteric glial cells (EGCs), which are involved in gut homeostasis, motility, and barrier integrity. This study compared the toxicological effects of pectenotoxin-2 (PTX2), yessotoxin (YTX), okadaic acid (OA), azaspiracid-1 (AZA1), 13-desmethyl-spirolide C (SPX), and palytoxin (PlTX) on the rat EGC cell line CRL2690. Cell viability, morphology, oxidative stress, inflammation, cell cycle, and specific glial markers were evaluated using RT-qPCR and high content analysis (HCA) approaches. PTX2, YTX, OA, AZA1, and PlTX induced neurite alterations, oxidative stress, cell cycle disturbance, and increase of specific EGC markers. An inflammatory response for YTX, OA, and AZA1 was suggested by the nuclear translocation of NF-&kappa, B. Caspase-3-dependent apoptosis and induction of DNA double strand breaks (&gamma, H2AX) were also observed with PTX2, YTX, OA, and AZA1. These findings suggest that PTX2, YTX, OA, AZA1, and PlTX may affect intestinal barrier integrity through alterations of the human enteric glial system. Our results provide novel insight into the toxicological effects of phycotoxins on the gut.

International audience; Although banned, dyes, such as Victoria pure blue BO (VPBO), are illicitly used in aquaculture to treat or prevent infections due to their therapeutic activities. The present study examined the formation of phase I and phase II metabolites derived from VPBO using trout liver microsomes and S9 proteins. The well-known malachite green (MG) dye was also studied as a positive control and to compare its metabolism with that of VPBO. First, we optimised the incubation conditions for the detection of VPBO and MG metabolites by studying the formation of cytochrome P450 (CYP) substrates. Using the determined conditions (2 h at 20 °C), we incubated VPBO with trout microsomal and S9 fractions induced with β-naphtoflavone, and analysed the supernatant in a LC-LTQ-Orbitrap-HRMS system. The in vitro assays led to the detection of 16 VPBO metabolites from Phase I reactions, arising in particular from reactions with CYP1A. No metabolites were detected from Phase II reactions. The main metabolite detected, deethyl-VPBO, was CID-fragmented to determine its chemical structure, and thus recommend a potential biomarker for the control of VPBO in farmed fish foodstuffs.

Introduction Chemical (eg pesticides, veterinary drugs, etc.) and bacteriological contaminants (eg. foodborne pathogens) could contaminate animal and plant derived food products for human consumption. Some antibiotic residues (eg. chloramphenicol, nitrofuran metabolites, dyes) are banned in foodstuffs of animal origin (eg. milk, meat, eggs, etc.) in European Union because of toxicological risks for the consumer. The European Regulation has set Minimum Required Performance Limits (MRPL) [1] or Reference Point for Action (RPA) for banned substances [2]. Food containing residues of substances at or above the MRPL or RPA are declared non-compliant and consignments are rejected from the consumer’s market. Screening methods are the first stage of food control and so are essential for food safety monitoring. Conventional screening methods are microbiological methods (eg. plate tests, tube tests), immunological methods (eg. ELISA, radioimmunoassays) or physico-chemical methods (Thin Layer Chromatography, High Performance Liquid Chromatography (HPLC), liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)). These methods sometimes lack of sensitivity or specificity; they also could be time and money consuming. There is thus a need to develop novel screening methods for antibiotic residues detection, preferably with the potential for the field-testing (eg. farm control, self-control). Electrochemical biosensors make it possible to develop a promising and economically interesting approach. Electrochemical immunosensor An innovative electrochemical method based on disposable Screen Printed Carbon Electrodes (SPCE), coupled to magnetic beads (MB), allowing the simultaneous detection of 3 families of antibiotics in milk, was published by a Spanish academic team [3]. This technique presents major advantages: low cost (eg. disposable electrodes, potentiostat), promising detection limits, portability, and possible automatisation. Our laboratory has evaluated the transferability of the method. An electrochemical immunosensor has been developed for the detection of chloramphenicol residues in milk as a proof of concept. The matrix effect (milk samples) was high and so sample preparation has to be improved to reduce matrix effects. The objective is to develop an amperometric bead-based immunosensor for the multiplex detection of banned antibiotics (eg. chloramphenicol, nitrofuran metabolites, dyes) in bovine milk. Method Antibodies (Abs) against antibiotics are grafted on the surface of magnetic beads (MBs). Milk samples and antibiotic conjugated with Horseradish peroxidase (HRP) are mixed with MBs-Abs. A competition occurs between the HRP conjugates and the antibiotic residues if present in the sample, for the binding to the antibody. The MBs are washed to remove free antibiotics and conjugates. Then, a Screen Printed Carbon Electrode (SPCE) with MBs on its surface (maintained by a magnet) is soaked into a buffer solution containing hydroquinone; when adding hydrogene peroxide (H2O2) to the solution, an amperometric signal is produced, due to the enzymatic activity of HRP and measured. The amperometric signal is inversely proportional to the antibiotic concentration in the sample. Results and Conclusions Screening methods for the detection of veterinary drugs in food products have to be validated according to the European regulation [1] and to the European guideline for the validation of screening methods [4]. After the development and the optimization of the analytical parameters (eg. sample preparation, HRP concentration, incubation time, applied potential, etc), the methods developed for single compounds will be evaluated and validated according to the European regulations. Then the single compound methods will be merged into one multiplex method if possible. The results will be presented to the conference, discussing the advantage sand drawbacks of amperometric biosensors for the screening of antibiotic residues in food products. References 1. Commission Decision (EC) N° 2002/657 of 12 August 2002 implementing Council Directive 96/23/EC concerning the performance of analytical methods and interpretation of results. 2002: Official Journal of European Communities. p. 8-36. 2. Commission Regulation (EC) N° 470/2009 laying down Community procedures for the establishment of residue limits of pharmacologically active substances in foodstuffs of animal origin 2009, The European parliement and the Council: Official Journal of the European Union p. 11-22. 3. Conzuelo F, Ruiz-Valdepeñas Montiel V, Campuzano S, Gamella M, Torrente-Rodríguez RM, Reviejo AJ, Pingarrón JM. 2014. Rapid screening of multiple antibiotic residues in milk using disposable amperometric magnetosensors. Anal. Chim. Acta. 820:32-38. 4. CRL, Guideline for the validation of screening methods for residues of veterinary medicines (initial validation and transfer). 2010: Available from:: Guideline_Validation_Screening_en.pdf. p. 1-18.

International audience; The European Food Safety Authority concluded in February 2018 that "most uses of neonicotinoid insecticides represent a risk to wild bees and honeybees". In 2016, the French government passed a law banning the use of the five neonicotinoids previously authorized: clothianidin, imidacloprid, thiamethoxam, acetamiprid and thiacloprid. In the framework of an expert assessment conducted by the French Agency for Food, Environmental and Occupational Health and Safety to identify possible derogations, we performed a thorough assessment of the available alternatives to the five banned neonicotinoids. For each pest targeted by neonicotinoids use, we identified the main alternative pest management methods, which we then ranked for (i) efficacy for controlling the target pest, (ii) applicability (whether directly useable by farmers or in need of further research and development), (iii) durability (risk of resistance in targeted pests), and (iv) practicability (ease of implementation by farmers). We identified 152 authorized uses of neonicotinoids in France, encompassing 120 crops and 279 pest insect species (or genera). An effective alternative to neonicotinoids use was available in 96% of the 2968 case studies analyzed from the literature (single combinations of one alternative pest control method or product × one target crop plant × one target pest insect). The most common alternative to neonicotinoids (89% of cases) was the use of another chemical insecticide (mostly pyrethroids). However, in 78% of cases, at least one non-chemical alternative method could replace neonicotinoids (e.g. microorganisms, semiochemicals or surface coating). The relevance of non-chemical alternatives to neonicotinoids depends on pest feeding habits. Leaf and flower feeders are easier to control with non-chemical methods, whereas wood and root feeders are more difficult to manage by such methods. We also found that further field studies were required for many promising non-chemical methods before their introduction into routine use by farmers. Our findings, transmitted to policymakers, indicate that non-chemical alternatives to neonicotinoids do exist. Furthermore, they highlight the need to promote these methods through regulation and funding, with a view to reducing pesticide use in agriculture.

International audience

National audience; Les médicaments vétérinaires et les additifs utilisés en alimentation animale sont prescrits et utilisés intentionnellement, selon des itinéraires strictement encadrés (posologie, temps d'administration et de retrait avant l'abattage) pour garantir leur sécurité et leur efficacité. Toutes ces substances sont évaluées en termes de risque avant d'être autorisées et mises à disposition sur le marché. En particulier, l'usage des médicaments vétérinaires ne doit pas conduire à des concentrations de résidus excédant la limite maximale de résidus (LMR) dans les denrées alimentaires issues d'animaux exposés à ces substances. Par ailleurs, certaines substances sont interdites en production animale. L'évaluation des médicaments vétérinaires est conduite par l'Agence européenne du médicament (EMA). Elle permet la fixation des LMR dans les denrées alimentaires d'origine animale (DAOA), fondée sur la notion de temps d'attente, et à l'établissement de la liste des principes actifs autorisés (directive 2001/82/CE, règlement 2009/470/ CE). Plusieurs familles de médicaments vétérinaires sont autorisées chez les volailles : antibiotiques, antiparasitaires, anthelminthiques, anticoccidiens. En France, les anticoccidiens représentent chez la volaille la classe de principes actifs la plus utilisée, après les antibiotiques. Cependant, le nombre de molécules disponibles est restreint chez les poules pondeuses en raison de la production d'oeufs en continu et du risque de transfert des résidus dans l'oeuf. Les traitements s'effectuent essentiellement par la voie orale : eau de boisson ou aliment pendant cinq jours en moyenne. La voie parentérale représente moins de 1 % des lots. Le respect des temps d'attente est particulièrement délicat chez les poules pondeuses dans la mesure où le producteur doit retirer du marché sa production d'oeufs pendant le traitement et, dans certains cas, plusieurs jours après le traitement. Les molécules, qui ont obtenu une LMR pour les oeufs, ne dépassent pas le plus souvent cette LMR pendant les traitements préconisés par le vétérinaire. L'évaluation des additifs alimentaires est conduite selon le règlement 2003/1831/CE par l'Autorité européenne de sécurité sanitaire des aliments (EFSA). Certains des additifs coccidiostatiques, autorisés chez les poulets de chair, les dindes ne sont autorisés chez les poulettes destinées à la ponte que jusqu'à l'âge de 12 à 16 semaines. Tous les additifs antibiotiques sont interdits dans l'Union européenne depuis le 01/01/2006. Objectifs du dispositif de surveillance-Références réglementaires Les plans de contrôle officiels visent à relever les traces éventuelles de résidus de médicaments, dans la viande (muscle) et les oeufs, dont le risque en termes de santé publique a été préalablement évalué et a conduit à la définition des LMR dans ces denrées pour les substances autorisées (règlement (UE) N° 37/2010). Les médicaments contenant les substances autorisées sont soumis à une évaluation en vue de la délivrance d'une AMM conduisant à la détermination des temps d'attente à respecter entre la dernière administration du médicament et la commercialisation des produits issus de l'animal (viande, oeufs, abats). Le respect des modalités d'utilisation (voie d'administration, posologie) et du temps d'attente permet de garantir avec une très forte probabilité des niveaux de résidus inférieurs aux LMR et une absence de risque toxicologique pour le consommateur. À côté de ces plans visant les substances autorisées ou non dans la filière volailles, d'autres plans de contrôle officiels ciblent les substances actuellement interdites en production animale, telles que le chloramphénicol, les nitrofuranes et les nitroïmidazoles. Les prélèvements sont inopinés et ciblés. Ils sont réalisés selon les modalités fixées par la décision 98/179/CE. Le dispositif de surveillance des résidus de médicaments vétérinaires dans les volailles et les oeufs Brigitte Roudaut (brigitte.roudaut@anses.fr) (1), Isabelle Fournet (isabelle.fournet@agriculture.gouv.fr) (2) (1) Anses, Laboratoire de Fougères, Laboratoire de référence résidus de médicaments vétérinaires, Fougères, France (2) Direction générale de l'Alimentation, Bureau des intrants et de la santé publique en élevage, Paris, France Dispositif de surveillance des résidus de médicaments vétérinaires dans les volailles et les oeufs Résumé Certaines substances chimiques introduites de manière volontaire (médicaments vétérinaires, additifs) ou frauduleuse (substances interdites) dans l'alimentation (eau de boisson, aliment) des volailles sont susceptibles d'être transférées vers les muscles chez les volailles et aussi vers l'oeuf chez les femelles pondeuses (poule, caille…). Dans l'Union européenne, alors que certains antibiotiques sont enregistrés en tant médicaments vétérinaires (règlements 470/2009/CE et 37/2010/UE), la plupart des anticoccidiens sont enregistrés comme additifs selon le règlement 1831/2003/CE, relatif aux additifs destinés à l'alimentation des animaux. Le présent article a pour objectif de présenter un bilan des résultats des plans de contrôle français pour les antibiotiques, anthelmintiques, anticoccidiens et antiinflammatoires non stéroïdiens (AINS) dans les muscles de volailles (poulet de chair, dinde, autres volailles) et dans les oeufs (poule, caille) pour l'année 2015. Les résultats montrent que les volailles et les oeufs commercialisés sont en grande majorité exempts de résidus de médicaments vétérinaires. La mise en place du Paquet hygiène devrait permettre de diminuer encore le taux de non-conformité pour certaines de ces substances et de garantir les produits vis-à-vis de ces risques. Mots-clés Plan de contrôle, plan de surveillance, volailles, viande, oeufs, antibiotiques Abstract Surveillance of veterinary drug residues in poultry meat and eggs Some chemicals introduced intentionally (veterinary drugs, additives) or illegally (banned substances) in the diet (drinking water, feed) of poultry are likely to be transferred to the muscles and also to the egg in laying females (hens, quails, etc.). In the EU, while some antibiotics are registered as veterinary drugs (Regulations (EC) No 470/2009 and (EC) No 37/2010), most coccidiostats are registered as additives in accordance with Regulation (EC) No 1831/2003 on additives for animal feed. This paper aims to present the results of French control plans for antibiotics, anthelmintics, coccidiostats and non-steroidal anti-inflammatory drugs (NSAIDs) in poultry meat (broilers, turkeys, other poultry) and eggs (hens, quails) for 2015. The results show that most poultry and eggs are marketed free of veterinary drug residues. The implementation of the Hygiene Package should further reduce the non-compliance rate for some of these substances and guarantee products against these risks.

Article sous presse; Bacillus cereus sensu lato is composed of a set of ubiquitous strains including human pathogens that can survive a range of food processing conditions, grow in refrigerated food, and sometimes cause food poisoning. We previously identified the two-component system CasK/R that plays a key role in cold adaptation. To better understand the CasK/R-controlled mechanisms that support low-temperature adaptation, we performed a transcriptomic analysis on the ATCC 14579 strain and its isogenic ∆casK/R mutant grown at 12°C. Several genes involved in fatty acid (FA) metabolism were downregulated in the mutant, including desA and desB encoding FA acyl-lipid desaturases that catalyze the formation of a double-bond on the FA chain in positions ∆5 and ∆10, respectively. A lower proportion of FAs presumably unsaturated by DesA was observed in the ΔcasK/R strain compared to the parental strain while no difference was found for FAs presumably unsaturated by DesB. Addition of phospholipids from egg yolk lecithin rich in unsaturated FAs, to growth medium, abolished the cold-growth impairment of ΔcasK/R suggesting that exogenous unsaturated FAs can support membrane-level modifications and thus compensate for the decreased production of these FAs in the B. cereus ∆casK/R mutant during growth at low temperature. Our findings indicate that CasK/R is involved in the regulation of FA metabolism, and is necessary for cold adaptation of B. cereus unless an exogenous source of unsaturated FAs is available.