Infant Food Samples Research Articles

Isolation and characterization of Cronobacter spp. from environmental and food resources

Cronobacter spp. (formerly Enterobacter sakazakii) has been isolated from a wide range of environmental and several food sources. Cronobacter spp. is an opportunistic pathogen causing serious infection in infants, particularly neonates. The aim of this study was to isolate and characterize Cronobacter spp. from food sources (infant food, herbs and spices and vegetables) and from environmental sources as dust from vacuum cleaners. Isolation of Cronobacter spp. was performed on selective chromogenic agars, fi rstly using commercial ESIA agar and thereafter on Kim and Rhee-KR agar described in the literature. Phenotypic characteristics were obtained by commercial miniaturized biochemical ENTEROTEST 24 kits and the fi nal confi rmation of isolated strains was performed by molecular techniques (PCR, PCR DGGE analysis, and 16S rDNA sequencing). Altogether, 99 samples were analyzed (47 samples of foods and 52 samples of dust). In total, 43 isolates of presumptive Cronobacter spp. were initially identifi ed, however, only 22 isolates (51%) were identifi ed as Cronobacter spp. with high identity scores (75-99%). The occurrence of presumptive cronobacters in environmental samples was signifi cantly higher than in samples of food (18 out of 52 vs. 4 out of 47; P = 0.003). No cronobacters were found in 17 samples of infant food, 3 isolates originated from herbs and spices, 1 isolate from spinach and 18 isolates from samples of dust (households, restaurants, dormitory rooms). It can be concluded that Cronobacter spp. is a ubiquitous pathogen contaminating food and environment. Cronobacter spp. could be well identifi ed by means of ENTERO24 test kits with high probability. Both phenotypic and genotypic methodology could be used for identifi cation of Cronobacter spp. and they can be combined for reliable identifi cation.

Characterization of Staphylococcus aureus isolated from powdered infant formula milk and infant rice cereal in China

Dry infant foods are not sterile and could be contaminated with various bacteria including certain pathogens. The aim of this study was to investigate the prevalence of Staphylococcus aureus in infant foods and to characterize these strains. A total of 367 infant food samples, including 143 samples of powdered infant formula milk (PIF) and 224 samples of infant rice cereal (IRC), were collected in the Shaanxi Province of China during the period of July to August 2010 and screened for S. aureus. All S. aureus isolates were characterized by antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE), and detection of genes encoding enterotoxins, exfoliative toxins, Panton-Valentine leukocidin (PVL), and toxic shock syndrome toxin 1. Among all the samples examined, sixteen of 143 PIF samples (11.2%) and 14 of 224 IRC samples (6.3%) were positive for S. aureus. From these positive samples, 29 S. aureus strains were isolated from PIF and 25 from IRC. Of these S. aureus isolates, 83.3% were resistant to at least one antimicrobial, 35.2% to three or more antimicrobials. Resistance was most frequently observed to erythromycin (75.9%), followed by ciprofloxacin (51.9%) and trimethoprim/sulfamethoxazole (27.8%), while significantly fewer isolates were resistant to gentamicin (22.2%), tetracycline (18.5%), or cefoxitin (3.7%). In addition, 63.0% of isolates were positive for one or more toxin genes tested. The three most predominant toxin genes were pvl (40.7%), seg (38.9%), and sec (18.5%), followed by sea (7.4%), seb (7.4%), sed (5.6%), and see (5.6%). The ets, tsst-1, seh, sei, and sej genes were not detected. A total of 39 PFGE patterns were generated among 51 selected food isolates. Our findings indicate that PIF and IRC in the Shaanxi province were contaminated with S. aureus, and many S. aureus isolates harbored multiple toxin genes and exhibited multiple antimicrobial resistance. In addition, these S. aureus isolates were genetically diverse. The presence of S. aureus strains in these infant foods poses a potential threat to infant health.

PCR detection of Alternaria spp. in processed foods, based on the internal transcribed spacer genetic marker.

The genus Alternaria is considered one of the most important fungal contaminants of vegetables, fruits, and cereals, producing several mycotoxins that can withstand food processing methods. Conventional methods for Alternaria identification and enumeration are laborious and time-consuming, and they might not detect toxigenic molds inactivated by food processing. In this study, a PCR method has been developed for the rapid identification of Alternaria spp. DNA in foodstuffs, based on oligonucleotide primers targeting the internal transcribed spacer (ITS) 1 and ITS2 regions of the rRNA gene. The specificity of the Alternaria-specific primer pair designed (Dir1ITSAlt-Inv1ITSAlt) was verified by PCR analysis of DNA from various Alternaria spp., and also from several fungal, bacterial, yeast, animal, and plant species. The detection limit of the method was 10(2) CFU/ml in viable culture, heated culture, or experimentally inoculated tomato pulp. The applicability of the method for detection of Alternaria spp. DNA in foodstuffs was assessed by testing several commercial samples. Alternaria DNA was detected in 100% of spoiled tomato samples, 8% of tomato products, and 36.4% of cereal-based infant food samples analyzed.

Determination of Dodine in Fruit Samples by Liquid Chromatography Electrospray Ionization-Tandem Mass Spectrometry

A rapid and sensitive LC/electrospray ionization-MS/MS method has been developed for the determination of dodine in fruit samples. Based on a liquid-liquid extraction of 10 g solid fruit homogenate using an acetone-dichloromethane-hexane mixture and acetate ammonium buffer (pH 4.5), this LC/MS/MS procedure was characterized by recoveries above 50%, with good intra-assay precision (RSD < 13%) and interassay precision (RSD < 18%) for seven different matrixes (apple, apricot, cherry, peach, pear, plum, and quince). This method was validated from 5 to 500 microg/kg according to standard guidelines. Its LOD (1 microg/kg) and LOQ (5 microg/kg) were in accordance with recommendations of the European legislation defined for infant food [maximum residue level (MRL) = 10 microg/kg]. The whole procedure was finally tested on 1022 fruit samples intended for commercialization, both infant food samples and samples not intended in particular for babies. In this study, dodine was detected in 27 samples; none exhibited a concentration higher than the MRL.

Fast Determination of Manganese in Milk and Similar Infant Food Samples Using Multivariate Optimization and GF AAS

Manganese is an essential element, but high levels in foods can be toxic mainly for children. A fast and efficient method to determine Mn in milk and other infant foods using slurries and liquid samples is presented. Slurries were prepared in ultrapure water with 10 minutes of sonication. Liquid samples were diluted in ultrapure water when necessary. Multivariate optimization was used to establish some optimal analytical parameters through a fractional factorial design and a central composite design. Slurred and diluted samples were analyzed directly by GF AAS. The method presented limit of detection of (0.98 ± 0.04) μg L−1, characteristic mass of (2.9 ± 0.3) pg (recommended value 2 pg), RSD of 2.3% (n = 5), and linear range from 0.98 to 20.0 μg L−1 using iridium as permanent modifier. The accuracy was evaluated analyzing two certified reference materials: nonfat milk powder (SRM1549) and whole milk powder (SRM8435). The powdered samples concentrations were between 0.210 and 26.3 μg g−1.

PCR detection and identification of Alternaria species-groups in processed foods based on the genetic marker Alt a 1

In this study, a PCR method based on oligonucleotide primers targeting the Alt a 1 gene has been developed for the rapid detection of DNA from Alternaria spp. and for identification of Alternaria alternata, Alternaria porri, Alternaria radicina, and Alternaria infectoria species-groups in raw materials and processed food products. The assay design consists of two steps. First, a duplex PCR using primers Dir5cAlta1–Inv4Alta1 (that amplifies a specific DNA fragment of approximately 195 bp in all Alternaria spp.) and 18Sfweu–18Srveu (that amplifies a conserved 99 bp fragment on all the eukaryotic species), allows detection of Alternaria spp. DNA in foodstuffs with a high sensitivity and specificity. As a second step, identification of Alternaria species-groups is obtained through a seminested PCR method, without the need for sequencing PCR products. The specificity of the primer pairs designed was verified by PCR analysis of DNA from various Alternaria cultures, and also from several non target species. The detection limit of the method was approximately 10 2 CFU/ml, either in viable culture, heat inactivated culture or inoculated tomato pulp. Nevertheless, a sensitivity of 10 3 CFU/ml was obtained for tomato pulp inoculated with A. alternata or A. porri cultures heat inactivated at 90 °C for 5 min. PCR analysis of commercial foodstuff samples demonstrated the presence of DNA from A. alternata species-group in 100% of spoiled tomato samples, and 8% of tomato products, whilst 36.4% of cereal based infant food samples analyzed contained DNA from A. infectoria species-group.

The occurrence of arthropods in processed rice products in Malaysia

Objective To determine distribution of arthropods in processed rice products such as rice flour and rice cereal-based infant food. Methods Random samples of rice flour and rice cereal-based infant food purchased from commercial outlets were examined for the presence of arthropods using a modified Berlese Tullgren Funnel Method. Mites were mounted prior to identification and weevils were directly identified. Results For non-expired products, infestation was found in 6.7% of rice flour and none was found in rice cereal-based infant food samples. The arthropods found in the flour samples were Cheyletus spp., Suidasia pontifica (S. pontifica), Tarsonemus spp., Tyrophagus putrescentiae (T. putrescentiae), Sitophilus granarius (S. granarius) and Sitophilus oryzae (S. oryzae). Others which cannot be identified were Oribatid and Prostigmatid mites. The most common mites in rice flour were Tarsonemus spp. (69.1%), followed by S. pontifica (18.2%). For expired products, only one sample of rice cereal-based infant food was infested and the infestation was by mites of the family Tydeidae. Conclusions This study demonstrates the presence of 4 allergenic species of S. pontifica, T. putrescentiae, S. granarius and S. oryzae in rice flour. These arthropods can contribute to the incidence of anaphylaxis upon consumption by atopic individuals. There was no infestation of arthropods in rice cereal-based infant food surveyed except for an expired product in a moderate rusty tin container.

Direct Determination of Molybdenum in Milk and Infant Food Samples Using Slurry Sampling and Graphite Furnace Atomic Absorption Spectrometry

A fast and efficient method to determine molybdenum, Mo, in milk and other infant food by atomic absorption spectrometry with electrothermal atomization employing slurry sampling was developed. Slurries were prepared in ultrapure water with 5 to 20 min of sonication in concentrations of 10% w/v. The injection of 5.0 µL of a 0.1% (v/v) cetyl trimethyl ammonium chloride solution before the temperature program reduced the effect of build-up of carbonaceous residues within the atomizer. Europium (chemical modifier) and niobium (permanent modifier) were chosen for use from several potential modifiers. The parameters of merit were obtained in the optimized conditions Ta = 2,700 oC, Tp = 2,000 oC, tp = 20 s, and Eu 5.0 μg + permanent Nb 500.0 μg. These parameters were linear working range up to 100.0 μg/L, limit of detection (1.1 ± 0.1) μg/L, aqueous calibration, and standard addition curves with r2 > 0.9900 and relative standard deviation of 0.6% to 8.7%. The accuracy was evaluated by recovery tests and by certified material analysis; the agreement among these numbers validated the method. The powdered sample concentrations were between 39 and 1,570 µg/kg.

Analysis and Migration of Phthalates in Infant Food Packed in Recycled Paperboard

The contamination of infant food with substances from its packaging due to migration processes is still a problem. Most recently, great attention was paid to the migration of epoxidized soybean oil (ESBO) and phthalates from twist-off closures into baby food packed in glass jars. Besides, packaging made of recycled fiber materials such as paper and paperboard were found to be the source of contaminants in dry and powdery foodstuffs such as sugar, rice, and maize flour. In this study 20 infant food samples packed in recycled paperboard containers were tested for phthalates and diisopropyl naphthalenes (DIPN), known incorporated substances in recycled paper. Furthermore, the barrier function of different secondary packaging materials (paper and aluminum-coated foil) was investigated. The highest contents of phthalates (mainly diisobutyl phthalate, DiBP) and DIPN in infant food samples were found for those foods packed in inner bags made of paper. Migration experiments were performed under authentic conditions to evaluate possible transfer mechanism (gas phase, direct contact) of phthalate esters into foodstuff. It is shown that paper does not provide an appropriate barrier against migration of semipolar compounds such as phthalates. The air space itself otherwise effectively prevents migration of the less volatile phthalates under the applied conditions.

Impact of food processing and storage conditions on nitrate content in canned vegetable-based infant foods.

The nitrate and nitrite contents were determined in canned vegetable-based infant foods of five varieties. Furthermore, changes in nitrate content during industrial processing were studied. Samples were taken from raw materials, homogenized mixtures, and final products after sterilization, and then analyzed for nitrate and nitrite content by high-pressure liquid chromatography. Processing steps preceding heat treatment, such as vegetable peeling and washing, decreased the nitrate concentrations in the range of 17 to 52%. During processing, the nitrate content in canned infant foods decreased 39 to 50%, compared with nitrate concentration in the raw-vegetable mixture. The final nitrate concentration in infant foods depends mainly on the initial nitrate content of the raw-vegetable mixture. The effect of storage time (24 and 48 h) and temperature (4 to 6 degrees C and 20 to 22 degrees C) on nitrate and nitrite content in opened canned infant-food samples was studied. After 24 h of storage at refrigerated and room temperatures, the mean nitrate content increased on average by 7 and 13%, and after 48 h of storage by 15 and 29%, respectively. The nitrite content in all analyzed samples was below the quantification limit. Storage requirements of industrial manufacturers must be followed strictly. Opened can foods, stored under refrigerated conditions, have to be consumed within 2 days, as recommended by manufacturers. The infant-food producers must pay more attention to the quality of raw materials. Nitrate content analyses should be added as compulsory tests to the quality assurance programs.

Evaluation of Some Antibiotics Against Pathogenic Bacteria Isolated from Infant Foods in North Africa

Eighty four samples of commercial infant foods in Libya were examined for microbiological quality. Bacillus cereus, B. stearothermophilus, B. licheniformis, Staphylococcus xylosus, S.lentus, Enterobacter sakazakii, E. aerogenes were isolated from the samples. Over 64.3 % of the samples contained high counts of Bacillus spp (� 2 log10 CFU/g), 42.9% Staphylococcus spp (� 2 log10 CFU/g) and 26.3% Enterobacteriaceae (� 2 log10 CFU/g). The moulds isolated were mainly of the genera, Aspergillus and Penicillium. In relation to antibiotic resistance Bacillus spp showed the highest level of resistance to bacittracin (63.6%), ampicillin (54.5%), cephalosporin (36.4%), penicillin (18.1%) and nalidixine acid (18.2%). Corresponding values for Staphylococcus spp were bacitracin 60%, erythromycin 30%, penicillin 30%, cepha- losporin 10%, nalidixic acid 10% and ampicillin 10%, respectively. Enterobacteriaceae strains were resistant to bacitracin (100%), erythromycin (62.5%), ampicillin (37.5%), cephalosporin (25%) and nalidixine acid (12.5 %). Bacillus spp, Staphylococcus spp and Enterobacteriaceae were susceptible to chloramphenicol, kanamycin, gentamicin and streptomy- cin.

Isolation of Cronobacter spp. (formerly Enterobacter sakazakii) from infant food, herbs and environmental samples and the subsequent identification and confirmation of the isolates using biochemical, chromogenic assays, PCR and 16S rRNA sequencing

BackgroundCronobacter spp. (formerly Enterobacter sakazakii), are a group of Gram-negative pathogens that have been implicated as causative agents of meningitis and necrotizing enterocolitis in infants. The pathogens are linked to infant formula; however, they have also been isolated from a wide range of foods and environmental samples.ResultsIn this study, 233 samples of food, infant formula and environment were screened for the presence of Cronobacter spp. in an attempt to find its source. Twenty nine strains were isolated from samples of spices, herbs, infant foods, and dust obtained from household vacuum cleaners. Among the 76 samples of infant food, infant formula, milk powder and non-milk dairy products tested, only one sample of infant food contained Cronobacter spp. (1.4%). The other Cronobacter spp. isolates recovered include two from household vacuum dust, and 26 from 67 samples of herbs and spices. Among the food categories analyzed, herbs and spices harbored the highest number of isolates, indicating plants as a possible reservoir of this pathogen. Initial screening with API 20E test strips yielded 42 presumptive isolates. Further characterization using 3 chromogenic media (α-MUG, DFI and EsPM) and 8 sets of PCR primers detecting ITS (internal transcribed spacer sequences), 16S rRNA, zpx, gluA, gluB, OmpA genes followed by nucleotide sequencing of some PCR amplicons did not confirm the identity of all the isolates as none of the methods proved to be free of both false positives or false negatives. The final confirmation step was done by 16S rRNA sequence analysis identifying only 29 of the 42 isolates as Cronobacter spp.ConclusionOur studies showed that Cronobacter spp. are highly diverse and share many phenotypic traits with other Enterobacteriaceae members highlighting the need to use several methods to confirm the identity of this pathogen. None of the biochemical, chromogenic or PCR primers proved to be a reliable method for confirmation of the identity of the isolates as all of them gave either false positives or false negatives or both. It is therefore concluded that 16S rRNA sequencing is pivotal to confirm the identity of the isolates.

Concentração de fluoreto em arroz, feijão e alimentos infantis industrializados

To determine fluoride concentrations in the typical Brazilian meal (rice with beans) and in processed infant foods, and to estimate their contribution towards dental fluorosis. The foods were purchased at supermarkets in the cities of Piracicaba and Campinas, Southeastern Brazil. The processed infant foods were bought in 2001 and the rice and beans in 2003, and they were analyzed immediately. Three brands of rice, three brands of beans and 36 samples of infant foods were analyzed, divided into five groups: ready-to-eat, porridges, formulated foods, powdered milk and others. For the rice and beans, fluoride concentrations were determined in the raw grains and after they were cooked with fluoridated (0.7 ppm) or distilled water. All the fluoride analyses were performed using a specific electrode. A dose of 0.07 mg/kg/day was considered to be the upper limit of fluoride exposure in terms of fluorosis risks. The fluoride concentrations found in the grains of rice and beans were low. However, they increased 100 to 200-fold after cooking in fluoridated water. Even so, they were lower than what is found in some processed foods. A meal of rice and beans prepared with fluoridated water would be responsible for 29% of the threshold dose for fluoride intake in terms of acceptable fluorosis; the contribution from some processed foods reaches 45%. The typical Brazilian food, even when prepared with fluoridated water, is safer in terms of the risk of dental fluorosis than are some processed infant foods.

Validation of an ion-pair liquid chromatography–electrospray-tandem mass spectrometry method for the determination of heterocyclic aromatic amines in meat-based infant foods

A method based on ion-pair liquid chromatography–electrospray tandem mass spectrometry (LC–MS/MS) is reported for determining heterocyclic aromatic amines (HAAs) in meat-based infant foods. The HAAs encompassed quinoline (IQ, MeIQ), quinoxaline (MeIQx), pyridine (PhIP), and carboline derivatives (AαC, Harman, Norharman) with d3-IQ, 13C2-MeIQx, and d3-PhIP used as labelled internal standards. The method used extraction into acetone followed by a clean-up on an SCX solid-phase extraction column. LC separation was performed on a TSKgel ODS-80TS column (250 × 2.0 mm, 5 µm), the mobile phase being an ammonium formate–formic acid buffer (3.03 mM ammonium formate, pH = 2.8) aqueous solution–acetonitrile gradient at a flow rate of 0.2 ml min−1. For unequivocal identification of each analyte, three ions were detected and chosen for selected reaction monitoring (SRM). Validation was carried out on lyophilized meat samples. Mean recoveries ranged between 78 ± 4% and 98 ± 2% for different analytes. Limits of quantification generally lower than 8 ng g−1 were demonstrated in meat samples for the analytes investigated. The method exhibited a good linearity and repeatability. Robustness testing identified those factors which were statistically significant in influencing chromatographic separation and response, and indicated which parameters have to be strictly controlled for a reliable analysis of HAAs. In particular, the mobile-phase flow rate was found to be statistically significant (α = 0.05) for the capacity factor (k′) of all analytes except for AαC peak, whereas the mobile-phase pH resulted to be a critical parameter for the k′ values of IQ, MeIQ, and Norharman. The method was proved to be robust vs. resolution between IQ and MeIQ peaks. Among mass-spectrometric parameters, collision energy was found to significantly affect quantitative response of all analytes except that of IQ. The applicability of the method to the analysis of meat-based infant food samples was demonstrated.

Fumonisins in Brazilian corn-based foods for infant consumption

A survey of 196 samples of corn-based infant foods from 13 cities of Sao Paulo State, Brazil, was carried out to investigate the fumonisin contamination in the products. Based on their ingredients, the products were divided into seven groups: infant cereal designated as types A–D, corn meal, corn starch and instant cereal baby food. Although certain infant food samples were free of fumonisin contamination (<20 μg kg−1; corn starch and infant cereals of type A, B and D), contamination levels in the other products (corn meal, instant corn-based baby food and cereal type C) were of concern, particularly those in corn meal. All samples in these categories contained fumonisins. The mean level for total fumonisins (FB1 + FB2 + FB3) in corn meal was 2242 μg kg−1 (maximum 8039 μg kg−1), in instant corn-based baby food was 437 (maximum 1096) μg kg−1 and in infant cereal type C was 664 (maximum 1753) μg kg−1.

Mycotoxins in infant cereal foods from the Canadian retail market

Three hundred and sixty-three samples of cereal-based infant foods were collected from the Canadian retail marketplace over 3 years. The samples included oat-, barley-, soy-, and rice-based infant cereals, mixed-grain infant cereals, teething biscuits, creamed corn, and soy-based formulas. Samples were analysed for targeted mycotoxins (deoxynivalenol, nivalenol, HT-2 toxin, zearalenone, ochratoxin A, fumonisins B1 and B2, and five ergot alkaloids). Soy-based cereals (which usually contain corn) exhibited the highest incidences of deoxynivalenol (100%), zearalenone (46%) and fumonisins (75%). Overall, deoxynivalenol was the most frequently detected mycotoxin — it was detected in 63% of samples analysed. Survey results demonstrated the regular occurrence of multiple mycotoxins in cereal-based infant foods.

Determination of hydroxymethylfurfural in commercial jams and in fruit-based infant foods

Fifty six commercial samples, 38 jams with several fruit and sugar contents and 18 fruit-based infant foods, were analysed for pH, dry matter and hydroxymethylfurfural (HMF) content. Samples of jams had pH and dry matter values similar to those reported in the literature. Fruit-based infant foods presented higher values of pH and lower dry matter than jam samples. HMF was found in all samples of jams, regardless of the pH, sugar or dry matter, from traces to 7.17 mg/100 g product (mean value close to 1.35 mg/100 g product). Three samples of fruit-based infant foods did not show appreciable amounts of HMF and the average value for the rest of samples was 0.29 mg/100 g product. The difference between the values of HMF in jams and in fruit-based infant foods may be in part due to the lower fruit concentration in the latter. In general terms, the considerable variations of HMF content found in the analysed samples may be an indication of differences in the processing conditions.

Development, validation, and application of an acetylcholinesterase-biosensor test for the direct detection of insecticide residues in infant food

A highly sensitive and rapid food-screening test based on disposable screen-printed biosensors was developed, which is suitable for monitoring infant food. The exposure of infants and children to neurotoxic organophosphates and carbamates is of particular concern because of their higher susceptibility to adverse effects. The European Union has, therefore, set a very low limit for pesticides in infant food, which must not contain concentrations exceeding 10 μg/kg for any given pesticide. The maximum residue limit (MRL) has been set to be near the determination threshold that is typically achieved for pesticides with traditional analytical methods. The biosensor method could detect levels lower than 5 μg/kg and thus clearly fulfills the demands of the EU. To substantiate these measurements, recovery rates were determined and amounted on average to 104% in food. Matrix effects were eliminated by the introduction of a special electrode treatment. The test was compared with two traditional pesticide multiresidue analysis methods (GC-MS, LC-MS) using 26 fruit and vegetable samples from local markets and 23 samples of processed infant food from Germany, Spain, Poland and USA. Three infant food samples exceeded the MRL of 10 μg/kg when analyzed by either biosensor test or multiresidue methods.

Furosine as indicator of maillard reaction in jams and fruit-based infant foods.

To investigate the presence of furosine in commercial samples of jams and fruit-based infant foods a simple method by ion-pair reversed-phase liquid chromatography is described. The yield of furosine during the hydrolysis with hydrochloric acid was optimized. The reproducibility in the repeatability and recovery of the method, expressed in relative standard deviation percentages, proved to be in the ranges of 4.1-8.3% and 1.0-4.4%, respectively. The recovery percentages of furosine varied between 86.7 and 95.3%. The obtained results support the suitability of the method. Furosine was detected in all studied samples. Although a high variability in the content of furosine was noticed, in general terms, the lowest levels of furosine were observed in samples of fruit-based infant foods and the highest were observed in jams of more than 60% sugar. These results could be due to different heat treatment, storage conditions, and/or differences in the values of water activity (a(w)) and amounts of sugar. The results obtained in the present paper point out the usefulness of furosine as an indicator of Maillard reaction for jams and fruit-based infant foods.

Determination of free amino acids in infant food by capillary zone electrophoresis with mass spectrometric detection.

A method for the quantitative determination of free amino acids in infant food samples using capillary electrophoresis (CE) with electrospray-mass spectrometric (ESI-MS) detection is presented. According to the zwitterionic nature of the analytes, two different modes of separation as well as detection were tested; highly acidic carrier electrolytes combined with MS detection in the positive ion mode proved to be the optimum solution. Sensitivity as well as linearity of the method were sufficient to allow the analysis of all solutes of interest in a single run. In this way, free amino acids could be analyzed in a variety of infant food preparations without any sample pretreatment or derivatization step.