Novel foods, food enzymes, and food additives derived from food by-products of plant or animal origin: principles and overview of the EFSA safety assessment.

The European Union (EU) is committed to transitioning toward a circular economy model, with food waste being one of the areas to be targeted. To close the loop of food waste generated during food processing and discarded at the retail or consumption phases, research and innovation parties proposed to valorize agro-food by-products to produce novel foods and food improvement agents (food additives, food enzymes, and food flavorings). In the EU, the authorization of such novel foods and food improvement agents is governed by different regulatory frameworks. A centralized safety assessment by the European Food Safety Authority (EFSA) is the prerequisite for their authorization through the so-called Union Lists. Up to December 2023, EFSA published 45 scientific opinions on the safety of novel foods, food enzymes, and food additives derived from by-products of plant and animal origin. The current study illustrates examples of these by-products for the production of novel foods or food improvement agents and the data requirements behind their respective safety assessments conducted by EFSA. In this review, applications on novel foods, food enzymes, and food additives received by EFSA were screened and analyzed to find the common scientific requirements and differences in terms of the safety evaluation of such products. Various by-products (i.e., corncobs, coffee husks, spent grains of barley and rice, grape pomace, pumpkin peels, bovine whey, eggshells, shrimp heads, and animal organs or tissues) were described in the applications as being processed (extraction, physical treatments, and chemical and enzymatic reactions) to obtain novel foods and food improvement agents. The heterogeneity and complexity of these products emphasize the challenge of their safety assessment, depending on the characteristics of each product. However, as this study shows, the scientific requirements underpinning their safety do not differ substantially in the different regulated product areas considered, with similar information needed to assess their safety in terms of identity, production process, compositional characterization, proposed/intended uses and exposure assessment, toxicological information, and allergenicity data. Additional nutritional information and data on the history of use are required in the case of novel foods.

Statement on safety of cannabidiol as a novel food: data gaps and uncertainties.

The European Commission has determined that cannabidiol (CBD) can be considered as a novel food (NF), and currently, 19 applications are under assessment at EFSA. While assessing these, it has become clear that there are knowledge gaps that need to be addressed before a conclusion on the safety of CBD can be reached. Consequently, EFSA has issued this statement, summarising the state of knowledge on the safety of CBD consumption and highlighting areas where more data are needed. Literature searches for both animal and human studies have been conducted to identify safety concerns. Many human studies have been carried out with Epidyolex®, a CBD drug authorised to treat refractory epilepsies. In the context of medical conditions, adverse effects are tolerated if the benefit outweighs the adverse effect. This is, however, not acceptable when considering CBD as a NF. Furthermore, most of the human data referred to in the CBD applications investigated the efficacy of Epidyolex (or CBD) at therapeutic doses. No NOAEL could be identified from these studies. Given the complexity and importance of CBD receptors and pathways, interactions need to be taken into account when considering CBD as a NF. The effects on drug metabolism need to be clarified. Toxicokinetics in different matrices, the half-life and accumulation need to be examined. The effect of CBD on liver, gastrointestinal tract, endocrine system, nervous system and on psychological function needs to be clarified. Studies in animals show significant reproductive toxicity, and the extent to which this occurs in humans generally and in women of child-bearing age specifically needs to be assessed. Considering the significant uncertainties and data gaps, the Panel concludes that the safety of CBD as a NF cannot currently be established.

Safety of iron hydroxide adipate tartrate as a novel food pursuant to Regulation (EU) 2015/2283 and as a source of iron in the context of Directive 2002/46/EC.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on iron hydroxide adipate tartrate as a novel food (NF) pursuant to Regulation (EU) 2015/2283 and as a source of iron in the context of Directive 2002/46/EC. The NF is intended to be used in food supplements up to a maximum dose of 100 mg per day, corresponding to a maximum daily intake of iron of 36 mg. The target population proposed by the applicant is the general population above 3 years of age. The NF which is the subject of the application is an engineered nanomaterial having primary particles, of almost spherical morphology, with a diameter typically smaller than 5 nm. The studies provided for absorption, distribution, metabolism and excretion (ADME) and bioavailability indicate that iron, once taken up into the epithelial cells of the gut, is subject to the same mechanisms of regulation and absorption as that of other forms of iron. Further studies provided in the context of the toxicological assessment indicate that the NF does not lead to iron bioaccumulation in tissues and organs at the doses tested. The Panel notes that the NF contains nickel at concentrations that may increase the risk of flare-up reactions in nickel-sensitised young individuals up to 10 years of age. In the 90-day toxicity study, findings related to haematology, clinical biochemistry and organ weights were observed and the Panel defined a no observed adverse effect level (NOAEL) of 231 mg/kg body weight (bw) per day, that is, the mid-dose used in the study. The Panel considers that the NF is a source from which iron is bioavailable and it is safe under the proposed conditions of use.

Novel foods in the European Union: Scientific requirements and challenges of the risk assessment process by the European Food Safety Authority.

The European Food Safety Authority (EFSA) has been involved in the risk assessment of novel foods since 2003. The implementation of the current novel food regulation in 2018 rendered EFSA the sole entity of the European Union responsible for such safety evaluations. The risk assessment is based on the data submitted by applicants in line with the scientific requirements described in the respective EFSA guidance document. The present work aims to elaborate on the rationale behind the scientific questions raised during the risk assessment of novel foods, with a focus on complex mixtures and whole foods. Novel foods received by EFSA in 2003-2019 were screened and clustered by nature and complexity. The requests for additional or supplementary information raised by EFSA during all risk assessments were analyzed for identifying reoccurring issues. In brief, it is shown that applications concern mainly novel foods derived from plants, microorganisms, fungi, algae, and animals. A plethora of requests relates to the production process, the compositional characterization of the novel food, and the evaluation of the product's toxicological profile. Recurring issues related to specific novel food categories were noted. The heterogeneous nature and the variable complexity of novel foods emphasize the challenge to tailor aspects of the evaluation approach to the characteristics of each individual product. Importantly, the scientific requirements for novel food applications set by EFSA are interrelated, and only a rigorous and cross-cutting approach adopted by the applicants when preparing the respective application dossiers can lead to scientifically sound dossiers. This is the first time that an in-depth analysis of the experience gained by EFSA in the risk assessment of novel foods and of the reasoning behind the most frequent scientific requests by EFSA to applicants is made.

Scientific opinion on the safety of selenite triglycerides as a source of selenium added for nutritional purposes to food supplements.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on selenite triglycerides as a novel food (NF) pursuant to Regulation (EU) 2015/2283, their safety when added for nutritional purposes to food supplements as a source of selenium and the bioavailability of selenium from this source, in the context of Directive 2002/46/EC. The proposed NF is the first lipophilic organic form of selenium so far described in the literature. It is composed by a mixture of individual Se-containing lipids which do not occur in nature. The Panel considers that the information provided on the composition of the NF does not allow a complete characterisation of the product. From the data provided to characterise the absorption, distribution, metabolism and excretion of the NF, it cannot be established in which chemical form Se is systemically available and if it can enter the functional Se body pool to fulfil Se physiological functions. The Panel considers that, since it is not demonstrated that the NF is converted to a known form of Se following ingestion and absorption, the NF is to be treated as a xenobiotic with unknown properties in the body. From a subchronic toxicity study in rats, the Panel derives a lowest observed adverse effect level (LOAEL) for general toxicity of 2 mg Se/kg body weight (bw) per day based on findings indicating liver as a target organ, as it has been shown for other studies on dietary Se. The Panel concludes that the NF is absorbed and provides Se, but in an unknown form of which the bioavailability has not been determined. The Panel also concludes that the safety of the NF under the intended conditions of use cannot be established.

Calcium l-methylfolate as a source of folate added for nutritional purposes to infant and follow-on formula, baby food and processed cereal-based food.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the extension of use of calcium l-methylfolate to be used as a source of folate added for nutritional purposes to infant and follow-on formula, baby food and processed cereal-based food pursuant to Regulation (EU) 609/2013. In 2004, EFSA assessed the use of calcium l-methylfolate as a source of folate in foods for particular nutritional uses, food supplements and foods intended for the general population. The new alternative synthetic step proposed to produce the nutrient source, using platinum as a catalyst, did not raise any safety concern and the production process was found to consistently yield a product in line with the proposed specifications. Based on the studies assessed in the previous evaluation, it was concluded that calcium l-methylfolate is non-genotoxic and that subchronic and embryotoxicity/teratogenicity studies in rats did not reveal any adverse effects up to the highest doses tested. The Panel considered that no additional toxicological studies are required on the nutrient source. The intervention study in healthy infants provided by the applicant did not indicate differences in growth and tolerance parameters in infants who consumed either an infant formula supplemented with calcium l-methylfolate or with folic acid, and did not raise concerns regarding safety or tolerability of the infant formula with the proposed nutrient source. The study also provided further supporting evidence for the bioavailability of calcium l-methylfolate. The Panel considers that calcium l-methylfolate is a source from which folate is bioavailable and concludes that calcium l-methylfolate is safe under the proposed uses and use levels for infants and young children.

Safety of nicotinamide riboside chloride as a novel food pursuant to Regulation (EU) 2015/2283 and bioavailability of nicotinamide from this source, in the context of Directive 2002/46/EC.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Allergens (NDA) was asked to deliver an opinion on nicotinamide riboside chloride as a novel food (NF) pursuant to Regulation (EU) 2015/2283, including an evaluation of the safety of its use in food supplements as a source of niacin, and the bioavailability of nicotinamide from this source, in the context of Directive 2002/46/EC. The NF, a synthetic form of nicotinamide riboside, is proposed to be used in food supplements for the healthy adult population at levels up to 300 mg/day. The production process, composition, specifications, batch-to-batch variability and stability of the NF do not raise safety concerns. Animal and human data indicate that the NF contributes to the nicotinamide body pool. There are no concerns regarding genotoxicity. Human studies do not raise safety concerns. The proposed maximum use level corresponds to an amount of nicotinamide, which is sixfold lower than the tolerable upper intake level (UL) set for adults, excluding pregnant and lactating women. The margin of exposure (MoE) of 70 derived from repeated dose toxicity studies with rats and dogs is considered sufficient for the adult population, excluding pregnant and lactating women. Regarding these two population groups, the MoE of 76 derived from a developmental toxicity study in rats is considered insufficient in the absence of data which could justify accepting a MoE lower than 100. The Panel concludes that the NF is safe under the proposed conditions of use for the healthy adult population, excluding pregnant and lactating women, and that an intake of the NF up to 230 mg/day is safe for pregnant and lactating women. The Panel also concludes that the NF is a source from which nicotinamide, a form of niacin, is bioavailable.

The principles and methods behind EFSA's Guidance on Uncertainty Analysis in Scientific Assessment.

To meet the general requirement for transparency in EFSA's work, all its scientific assessments must consider uncertainty. Assessments must say clearly and unambiguously what sources of uncertainty have been identified and what is their impact on the assessment conclusion. This applies to all EFSA's areas, all types of scientific assessment and all types of uncertainty affecting assessment. This current Opinion describes the principles and methods supporting a concise Guidance Document on Uncertainty in EFSA's Scientific Assessment, published separately. These documents do not prescribe specific methods for uncertainty analysis but rather provide a flexible framework within which different methods may be selected, according to the needs of each assessment. Assessors should systematically identify sources of uncertainty, checking each part of their assessment to minimise the risk of overlooking important uncertainties. Uncertainty may be expressed qualitatively or quantitatively. It is neither necessary nor possible to quantify separately every source of uncertainty affecting an assessment. However, assessors should express in quantitative terms the combined effect of as many as possible of identified sources of uncertainty. The guidance describes practical approaches. Uncertainty analysis should be conducted in a flexible, iterative manner, starting at a level appropriate to the assessment and refining the analysis as far as is needed or possible within the time available. The methods and results of the uncertainty analysis should be reported fully and transparently. Every EFSA Panel and Unit applied the draft Guidance to at least one assessment in their work area during a trial period of one year. Experience gained in this period resulted in improved guidance. The Scientific Committee considers that uncertainty analysis will be unconditional for EFSA Panels and staff and must be embedded into scientific assessment in all areas of EFSA's work.

Statement on the safety of d-ribose.

In 2018, the EFSA NDA Panel adopted the Scientific Opinion on the safety of d-ribose as a novel food pursuant to Regulation (EU) 2015/2283 when used in a variety of food, concluding that d-ribose is safe for the general population at intake levels up to 36 mg/kg body weight (bw) per day, but that its safety at the intended uses and use levels as proposed by the applicant could not be established. Following a request from the European Commission, the EFSA NDA Panel was asked to carry out a supplementary safety assessment for d-ribose by considering the new proposed uses and use levels submitted by the applicant. In order to address the present mandate, an intake assessment was carried out based on individual data from the EFSA Comprehensive European Food Consumption Database. Intakes were estimated for all age groups of the general population. The resulting ranges for the mean and high-level estimated intakes of d-ribose for all the population groups, including the target population groups, did not exceed the acceptable level of intake for the general population previously defined, i.e. 36 mg/kg bw per day, except for one survey on adolescents where the mean and 95th percentile of the intake estimates were 8.6 and 39.4 mg/kg bw per day, respectively. The Panel concludes that the novel food, d-ribose, is safe under the new proposed conditions of use.

Magnesium citrate malate as a source of magnesium added for nutritional purposes to food supplements.

The present scientific opinion deals with the assessment of the bioavailability of magnesium, from the proposed nutrient source, magnesium citrate malate (MgCM), when added for nutritional purposes to food supplements. MgCM is a mixed salt consisting of magnesium cations and citrate and malate anions, and with a magnesium content of 12-15%. MgCM is proposed to be used in food supplements that are intended to provide up to 300-540 mg/day magnesium. The data provided demonstrate that the production process results in batches of MgCM that comply with the product specifications and that the product is stable throughout its proposed shelf life. The human studies provided demonstrate that magnesium from MgCM is bioavailable. However, the extent of its bioavailability per se or compared to other magnesium sources cannot be established due to the lack of an appropriate magnesium source as a comparator in the studies provided or relevant kinetic data for magnesium. One publication provided in the dossier reported that supplementation with MgCM decreases calcium absorption, but this finding was not supported by publications on different magnesium salts and therefore the Panel could not draw conclusions from this finding. The Panel concludes that MgCM is a source from which magnesium is bioavailable, but the extent of its bioavailability cannot be established. The Panel notes that at the proposed maximum use levels of MgCM, the existing tolerable upper intake level for magnesium in nutritional supplements, water, or added to food and beverages (250 mg/day) is exceeded.

Safety of d-ribose as a novel food pursuant to Regulation (EU) 2015/2283.

Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on D-ribose as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The applicant intends to market the NF as ingredient in a variety of foods, food supplements and in certain foods for specific groups. The NF is produced by fermentation using a transketolase-deficient strain of Bacillus subtilis and marketed as Bioenergy Ribose™. The information provided on the batch-to-batch variability, specifications, stability, production process and history of the organism used as a source of the NF is sufficient and does not raise safety concerns. The Panel considers that the effects observed in a subchronic toxicity study in rats could be the consequence of nutritional imbalances, but toxicological effects could not be ruled out; from this study, the Panel derived a No observed adverse effect level (NOAEL) of 3.6 g/kg body weight (bw) per day. From the human studies indicating a potential decrease in glucose levels and/or the occurrence of transient symptomatic hypoglycaemia at intakes of 10 g of d-ribose, the Panel defined 70 mg/kg bw per day as the NOAEL with respect to hypoglycaemia that can be considered applicable for adults. For children, the Panel acknowledges the lack of human data directly relevant for this population group. Based on the NOAEL derived from the subchronic toxicity study in rats, an acceptable level of intake of 36 mg/kg bw per day was defined that would also take into account the potentially increased sensitivity of certain population groups to hypoglycaemia. The Panel concludes that the NF is safe for the general population at intake levels up to 36 mg/kg bw per day and considers that the safety of the NF at the intended uses and use levels as proposed by the applicant has not been established.

Scientific opinion on the evaluation of authorised ferric sodium EDTA as an ingredient in the context of Regulation (EC) 258/97 on novel foods and Regulation (EU) 609/2013 on food intended for infants and young children, food for special medical purposes and total diet replacement for weight control.

The present opinion deals with the evaluation of the proposed increase of the currently authorised maximum amounts of ferric sodium ethylenediaminetetraacetic acid (EDTA) as a novel food ingredient used as a source of iron, and its extension of use in processed cereal-based foods and baby foods. The applicant also provided information on two forms of ferric sodium EDTA, one previously assessed by EFSA and a new one of finer consistency. To support the proposed changes to the uses of ferric sodium EDTA, the applicant proposed a revision of the current acceptable daily intake (ADI) for EDTA, derived from that set for the food additive calcium disodium EDTA (E 385). The Panel confirmed that ferric sodium EDTA is a source from which iron is bioavailable. In assessing the safety of the proposed revision to the existing specifications for the novel food ingredient ferric sodium EDTA, the Panel noted that this would not discriminate between the previously evaluated substance and the one of finer consistency. In particular, the Panel noted that particle size was not one of the proposed parameters for the revised specifications. The Panel noted that it was not possible to determine whether particles of ferric sodium EDTA in the nano range were present in the product with finer consistency in the solid form. The toxicological data submitted did not add any new relevant information to the database on which the current ADI for EDTA is based. Consequently, the Panel concluded that there was no sound scientific justification to increase the ADI for EDTA and hence increase the use levels of ferric sodium EDTA or introduce additional uses as proposed by the applicant. The Panel recommended that additional toxicological data should be provided to address the shortcomings in the available toxicity database prior to the re-evaluation of calcium disodium EDTA (E 385).

Real time RNA transcription monitoring by Thiazole Orange (TO)-conjugated Peptide Nucleic Acid (PNA) probes: norovirus detection.

Thiazole Orange (TO)-conjugated Peptide Nucleic Acid (PNA) probes have been reported as a valuable strategy for DNA analysis; however, no investigations targeting RNA molecules and no comparisons between different derivatization approaches have been reported so far. In this work, two TO-conjugated PNAs for genogroup II noroviruses (NoV GII) detection were designed and synthesized. Both the probes target the most conserved stretch of nucleotides identified in the open reading frame 1-2 (ORF1-ORF2) junction region and differ for the dye conjugation strategy: one PNA is end-labelled with the TO molecule tethered by a linker; the other probe bears the TO molecule directly linked to the PNA backbone, replacing a conventional nucleobase. The spectroscopic properties of the two PNA probes were studied and their applicability to NoVs detection, using an isothermal assay, was investigated. Both probes showed good specificity and high fluorescence enhancement upon hybridization, especially targeting RNA molecules. Moreover, the two probes were successfully employed for NoVs detection from stool specimens in an isothermal-based amplification assay targeting RNA 'amplicons'. The probes showed to be specific even in the presence of high concentrations of non-target RNA.

Identification of PCR-amplified genetically modified organisms (GMOs) DNA by peptide nucleic acid (PNA) probes in anion-exchange chromatographic analysis.

PCR products obtained by selective amplification of transgenic DNA derived from food samples containing Roundup Ready soybean or Bt-176 maize have been analyzed by anion-exchange HPLC. Peptide nucleic acids (PNAs), oligonucleotide analogues known to bind to complementary single-stranded DNA with high affinity and specificity, have been used as specific probes in order to assess the identity of the peaks observed. Two different protocols were adopted in order to obtain single-stranded DNA: amplification with an excess of one primer or digestion of one DNA strand. The single-stranded DNA was mixed with the PNA probe, and the presence of a specific sequence was revealed through detection of the corresponding PNA:DNA peak with significantly different retention time. Advantages and limits of this approach are discussed. The method was tested with reference materials and subsequently applied to commercial samples.

Effect of ionic strength on PNA-DNA hybridization on surfaces and in solution.

Peptide nucleic acids (PNAs) are mimics of oligonucleotides containing a neutral peptidelike backbone and are able to bind complementary DNA targets with high affinity and selectivity. In order to investigate the effect of the ionic strength of the buffer solution, hybridization experiments with PNAs as (catcher) probes and DNAs as target oligonucleotides were performed in different salt solutions. Surface plasmon field-enhanced fluorescence spectroscopy was employed for real-time monitoring of DNA hybridizations to surface bound PNA. Probes with three different strand lengths were immobilized by self-assembly on the sensor surface. By introducing Cy5-labeled DNA targets the affinity constants, K(A)=k(on) (association)/k(off) (dissociation), were determined for fully complementary (MM0) as well as for single base mismatched (MM1) duplexes. Furthermore, the thermal stability of each duplex was determined by measuring melting curves in solution which was then compared to the kinetic and affinity parameters determined for the surface hybridization reactions. The results indicate that ions do not play a significant role for the PNA/DNA hybridization kinetics at surfaces. However, changes in the configuration of the PNA/DNA duplex due to the ionic strength variations influence the fluorescence yield drastically.

Kinetic and affinity analyses of hybridization reactions between peptide nucleic acid probes and DNA targets using surface plasmon field-enhanced fluorescence spectroscopy.

Peptide nucleic acid (PNA), a polyamide DNA mimic, has inspired the development of a variety of hybridization-based methods for the detection, quantification, purification, and characterization of nucleic acids owing to the stability of the PNA/DNA duplex. In this work, PNA probes complementary to a specific sequence of Roundup Ready soybean were immobilized onto a sensor surface via a self-assembled matrix employing streptavidin/biotin binding. The specific hybridization of PNA and DNA has been monitored by applying the chromophore-labeled DNA target oligonucleotides to the PNA modified Au sensor surface in real time using surface plasmon field-enhanced fluorescence spectroscopy. The authors demonstrate three kinds of experiments called global, titration, and kinetic analyses for the determination of rate constants for the association (k(on)) and dissociation processes (k(off)), and the affinity constant (K(A)) of the PNA/DNA duplex formation by fitting the data to a simple Langmuir model. Discrimination of a single base mismatched DNA (15mer) target on a 15mer PNA probe was documented, with a difference of the affinity constant of two orders of magnitude. Finally, the affinity constant for the hybridization of a long polymerase chain reaction product (169mer) obtained by amplification of DNA extracted from genetically modified soybean reference material has been determined by a kinetic-titration analysis. The results show the influence of a Coulomb barrier at high target surface coverage even for the hybridization to PNA at low ionic strength.

Development of a peptide nucleic acid array platform for the detection of genetically modified organisms in food.

Two previously developed platforms, a multiplex polymerase chain reaction (PCR) and a peptide nucleic acid (PNA) array, the former allowing for the simultaneous detection of five transgenes and two endogenous controls in food and feed matrices and the latter for the assessment of the identity of amplified PCR products, were combined in order to develop a PNA array device for the screening of genetically modified organisms (GMOs) in food. PNA probes were opportunely designed, synthesized, and deposited on commercial slides. The length of the probes as well as the distance of the probes from the surface were evaluated and found to be critical points. The most suitable probes were found to be 15-mer PNAs linked to the slide surface by means of two 2-(2-aminoethoxy)ethoxyacetic acids as spacers. The device was tested on a model system constituted by flour samples containing a mixture of standards at known concentrations of transgenic material, in particular Roundup Ready soybean and Bt11, Bt176, Mon810, and GA21 maize: The DNA was amplified using the specific multiplex PCR method and tested on the PNA array. The method proposed was found to be able to correctly identify every GMO present in the tested samples.

A microarray platform for parallel detection of five transgenic events in foods: a combined polymerase chain reaction-ligation detection reaction-universal array method.

We recently developed a multiplex polymerase chain reaction (PCR) system for the simultaneous detection of four transgenic maize (MON810, Bt176, Bt11, and GA21), one transgenic soybean (Roundup Ready), and two control genes (lectin and zein). Because PCR can lead to ambiguous interpretations due to low specificity, we have developed the ligation detection reaction (LDR) combined with a universal array as a molecular tool to confirm results of PCR analysis. Here, we describe the PCR-LDR-universal array procedure and demonstrate its specificity in revealing the presence of transgenic DNA in experimental samples, raw materials, and commercial foodstuffs.

Detection of genetically modified soybean using peptide nucleic acids (PNAs) and microarray technology.

Peptide nucleic acid (PNA) microarrays for the detection of Roundup Ready soybeans in food have been prepared. PNA probes are known to be more efficient and selective in binding DNA sequences than the analogous oligonucleotides and are very suitable to be used for diagnostics in food. PNAs of different lengths were carefully designed and synthesized by solid-phase synthesis on an automatic synthesizer adopting the BOC strategy. PNAs were purified by HPLC and characterized by HPLC/MS. The probes were spotted on a functionalized surface to produce a microarray to be hybridized with PCR products. DNA extracted from reference material was amplified using Cy3- and Cy5-labeled primers, and the fluorescent PCR products obtained were hybridized on the microarray. Two protocols were adopted: the hybridization with dsDNA or with ssDNA obtained by digestion with the enzyme lambda exonuclease. The best results were obtained using a 15-mer PNA probe in combination with the ssPCR product derived from enzymatic digestion. The method was applied to the analysis of a sample of certified transgenic soybean flour.

Development of a seven-target multiplex PCR for the simultaneous detection of transgenic soybean and maize in feeds and foods.

The detection of genetically modified organisms (GMOs) in food and feed is an important issue for all the subjects involved in raw material control, food industry, and distribution. Because the number of GMOs authorized in the EU increased during the past few years, there is a need for methods that allow a rapid screening of products. In this paper, we propose a method for the simultaneous detection of four transgenic maize (MON810, Bt11, Bt 176, and GA21) and one transgenic soybean (Roundup Ready), which allows routine control analyses to be sped up. DNA was extracted either from maize and soybean seeds and leaves or reference materials, and the recombinant DNA target sequences were detected with 7 primer pairs, accurately designed to be highly specific for each investigated transgene. Cross and negative controls were performed to ensure the specificity of each primer pair. The method was validated on an interlaboratory ring test and good analytical parameters were obtained (LOD = 0.25%, Repeatability, (r) = 1; Reproducibility, (R) = 0.9). The method was then applied to a model biscuit made of transgenic materials baked for the purpose and to real samples such as feed and foodstuffs. On account of the high recognition specificity and the good detection limits, this multiplex PCR represents a fast and reliable screening method directly applicable in all the laboratories involved in raw material and food control.