Analysis of vitamins A,E and C,iron and selenium contents in infant milk-based powdered formula during full shelf-life

The stability of vitamins A, E and C, and the iron and selenium content were determined in two types of long chain-polyunsaturated fatty acid (LC-PUFA) supplemented milk-based powdered infant formulas (IF), during an 18-month storage period at 25 and 40 °C. The first type (IF-A) was supplemented with vitamin A as retinol acetate. The second type (IF-B) was supplemented with vitamin A as retinol palmitate. Both types were also supplemented with vitamin E as α-tocopherol acetate and with vitamin C as ascorbic acid. The two formulas studied had higher vitamin A (140% and 139%), vitamin E (109% and 198%) and vitamin C (167% and 118%), but lower iron (65.0% and 65.3%) and selenium (72.9% and 79.4%) than the amounts declared on the label. As expected, all the studied vitamins showed decreases during storage, and these decreases were higher in formulas stored at 40 °C. The losses of vitamin A at 40 °C after 18 months of storage were 27.5% in IF-A and 29% in IF-B, while vitamin E losses under the same conditions were 23.1% and 28.1%, and vitamin C losses under the same conditions were 28.4% and 48.6%. All these losses justify the over-fortification of the aforementioned vitamins in these LC-PUFA supplemented IFs. Iron and selenium content remained unchanged throughout storage.     

Volatile compounds and fatty acid profiles in commercial milk-based infant formulae by static headspace gas chromatography: Evolution after opening the packet

The evolution of the volatile compounds propanal, pentanal and hexanal, and fatty acid profiles were examined in 20 infant formula (IF) milk powders during storage at 25 °C for 70 days after their packaging was opened. Few changes were observed in the fatty acid content during storage, but significant losses were found in C18:2 n − 6 and C18:3 n − 3 for some formulae. All three volatiles increased during storage in all formulae, confirming oxidative stability decreases once packets were opened. Significant correlation (p < 0.05) was detected between hexanal content and oxidation of n − 6 PUFA, specifically C18:2 n − 6 losses, and between propanal content and oxidation of n − 3 PUFA, specifically from C18:3 n − 3 losses.     

Quantification of water-soluble vitamins in milk-based infant formulae using biosensor-based assays

Vitamin analysis is essential for quality control and development of functional foods. In this study, a biosensor-based technology developed by Biacore AB was evaluated for analysis of water-soluble vitamins B₂, B₁₂, folic acid, biotin, and pantothenic acid used to supplement infant formula samples. Performance parameters such as accuracy, repeatability and recovery for the five vitamins were studied. The repeatability was measured in terms of relative standard deviation (RSD) and HORRAT_r value. The RSD for all vitamins was below 2% and the values of HORRAT_r were 0.16, 0.10, 0.15, 0.11 and 0.22, for B₂, B₁₂, folic acid, biotin, and pantothenic acid, respectively. The recovery of vitamins ranged from 94.7% to 109.1%. Linear analyses indicated that the square of the correlation coefficient (R²) for B₂, B₁₂, folic acid, biotin, and pantothenic acid were 0.993, 0.997, 0.993, 0.993 and 0.995, respectively. The results showed that the biosensor-based vitamin analysis technology is a sensitive, reliable and realistic alternative to other methods.     

Stability during storage of LC-PUFA-supplemented infant formula containing single cell oil or egg yolk

The medical community recommends that infant formulae should mimic human milk as far as possible, particularly in regards to long-chain polyunsaturated fatty acids (LC-PUFA). These include arachidonic acid (AA) and docosahexaenoic acid (DHA), both of which provide biochemical and functional benefits to neonates. However, LC-PUFAs are highly susceptible to oxidation and the composition of formulae must be carefully controlled. In this study, the stability of two types of LC-PUFA-supplemented milk-based powdered infant formula was evaluated over the course of 18 months storage at 25 °C and 40 °C. One contained egg yolk phospholipids (IF-EPL) and the other contained triacylglycerides (DHA and AA) synthesized by single cell oils (IF-SCO). The following parameters were monitored: peroxide values, volatile content (propanal, pentanal and hexanal), fatty acid profiles, and potential and free furfural content (5-hydroxymethyl-2-furaldehyde and 2-furaldehyde). In addition, these formulae were subjected to sensory evaluations by a panel of experts. The parameters studied revealed acceptable lipid stability in both types of formula, with better results for IF-EPL. At the end of the study period, significant deficits (p < 0.05) in linoleic acid were noted in both formulae. However, no significant decreases were observed in the other fatty acids, including AA and DHA. In regards to furfural content, both formulae exhibited a similar increase, indicative of the typical Maillard reaction characteristic of products stored for long periods.     

Geographical,seasonal and formula-specific variations in the selenium levels of infant formulae

Fortification of infant formulae with selenium (Se) is currently under consideration by manufacturers and regulatory bodies. However, information on the endogenous Se levels of infant formulae is largely lacking. The objective of this study was to describe the seasonal-, geographic- and formula-specific variations in endogenous Se levels of infant formulae.     

Evolution of free mono- and di-saccharide content of milk-based formula powder during storage

HPLC-RI was used to monitor saccharide evolution during the shelf-life of two types of milk-based formulae powders supplemented with microencapsulated long-chain polyunsaturated fatty acids (LC-PUFA): infant formula and formula for pregnant and/or lactating women. In addition, these powders were subjected to sensory evaluation. The powders were stored at 25, 37 and 47 °C. Lactose was detected in the infant formula (63 g/100 g), while in the formula for pregnant women, the following were found: lactose (25 g/100 g), fructose (15.8 g/100 g), sucrose (9.28 g/100 g) and lactulose (0.9 g/100 g). Microencapsulated LC-PUFA supplementation of milk-based formula powders did not affect sugar changes.     

Pesticide content of infant formulae and weaning foods available in New Zealand

A survey of the pesticide content of 25 commercially available infant formulae and 30 weaning foods available in New Zealand was undertaken in 1996. It included a representative mixture of imported and New Zealand manufactured infant foods. Three different pesticide screening techniques were used: a high-sensitivity organochlorine screen was carried out on all infant formulae, while a multiresidue screen (organochlorine and organophosphorus pesticides, synthetic pyrethroids, carbamate pesticides, fungicides and herbicides), and a specific screen for dithiocarbamate fungicides were both carried out on all weaning foods and on soy-based infant formulae. All results are expressed on a ready-to-feed basis. Extremely low levels of residues of three organochlorine compounds (p,p'-DDE, p,p'-DDT and dieldrin) were detected in infant formulae samples. Residues of p,p'-DDE were found in seven of 20 milk-based infant formulae at concentrations ranging from 0.03 to 0.5 μg kg^-1. Residues of p,p'-DDT were found in one imported milk-based infant formula at 0.7 μg kg^-1, and dieldrin residues were detected in four of five soy-based infant formulae at concentrations ranging from 0.05 to 0.08 μg kg^-1. The multiresidue pesticide screen detected low levels of residues of two organophosphorus pesticides; azinphos-methyl in one soy-based infant formula at a level of 22 μg kg^-1 and pirimiphos-methyl in two cereal-based weaning foods at concentrations of 5 and 14 μg kg^-1. None of the other approximately 140 pesticides (including fungicides and herbicides) included in the multiresidue screen were detected in any weaning foods or soy-based infant formulae, at a detection limit of 10 μg kg^-1. No residues of dithiocarbamate fungicides were detected in any product analysed, at a detection limit of 100 μg kg^-1.     

配方注册婴幼儿配方乳粉中蛋白质及三聚氰胺含量测定分析

目的通过测定婴幼儿配方乳粉中蛋白质及三聚氰胺含量,对我国现阶段配方注册的婴幼儿配方乳粉安全状况进行监测。方法婴幼儿配方乳粉中蛋白质的含量依照GB 5009.5-2016《食品安全国家标准食品中蛋白质的测定》中"第一法凯氏定氮法"进行检测;三聚氰胺的含量依照GB/T22388-2008《原料乳与乳制品中三聚氰胺检测方法》中"第一法高效液相色谱法"进行检测。结果样品中蛋白质含量均符合食品安全国家标准规定,且满足测定值不小于标签标示值80%的规定;三聚氰胺的含量均为未检出或低于检出限,符合原卫生部公告的限量值规定。结论根据食品安全国家标准或推荐标准的检测方法和评价指标,所检测的样品中蛋白质项目满足配方注册要求。     

Genistein and dicarboximide fungicides in infant formulae from the EU market

A method based on ultrasonic extraction and purification by solid phase extraction followed by LC–MS/MS and GC–MS analysis was developed for the determination of genistein, genistin, iprodione, vinclozolin and procymidone in infant powdered formulas. The method was tested for different formulations: milk, soy and hypoallergenic, and was applied to European pooled samples. Spike recoveries ranged from 53.1% to 91.5% and the relative standard deviation values for repeatability ranged from 9.6% to 17.7%, except for iprodione in milk formula (22.3%).     

Updating on the lysinoalanine content of commercial infant formulae and beicost products

Since the safety issue of lysinoalanine (LAL) still remains unresolved, its concentration in infant formulae should be reduced to a minimum. Data collected in the 1980s indicated that LAL is formed in higher amounts in liquid than in powdered formulae. Recently the market of liquid infant formulae is increasing rapidly and there are no new data, so 23 commercial powdered or liquid samples were investigated. In powdered samples, LAL was below the detection limit, whereas liquid adapted formulae contained up to 86 μg/g protein, liquid follow-on formulae up to 390 μg/g protein, and liquid growing milks up to 514 μg/g protein. The concentration of LAL in liquid formulae is considerably lower than in the past; however, the level in a few products remains rather high, especially compared with normal UHT-treated milk. Great differences were observed among products of different companies, which suggests that labelling with the thermal treatment applied would be very advisable. The investigation of some beicost products indicates that LAL is present only in products certainly containing milk proteins. Considering the rather low levels in comparison with liquid infant formulae, the contribution of beicost products to the total LAL daily intake does not seem to be particularly relevant.     

Effect of composition on the mechanical response of agglomerates of infant formulae

The objective of this paper is to investigate the relationship between the compositions of four typical infant formulae, the evolution of key quality characteristics during pneumatic conveying and the mechanical properties of individual agglomerates. Conveying experiments were conducted using a lab-scale rig. Four quality characteristics were measured before and after conveying: bulk density, volume mean diameter, wettability and percentage free fat. Relative breakages were calculated from particle size distributions. Uniaxial compression experiments were performed on individual agglomerates, giving forces and strains at failure and agglomerate stiffnesses. Coefficients of restitution of the agglomerates were obtained by video analyses of drop tests. The data indicate that bulk densities before conveying and the force and the strain of individual agglomerates at failure were related to the protein content. The force at failure and agglomerate stiffness were strongly correlated, and generally increased with increasing protein to fat ratio while the strain at failure decreased.     

婴儿配方乳粉中4种植物甾醇的含量研究

目的气相色谱法分析我国市场上销售的30批次婴儿配方乳粉,研究其中的4种植物甾醇含量分布情况。方法样品中加入内标5-α胆甾烷醇溶液和10%乙酰氯甲醇溶液,在80℃水浴中甲酯化2 h,用甲苯萃取。加入碳酸钠溶液(6 g/100 mL)使其分层,取上层甲苯溶液氮吹浓缩后,定容至1.0 mL,用气相色谱仪分析。结果婴儿配方乳粉中4种植物甾醇含量在23.9～148.9 mg/kg之间,β-谷甾醇含量最高,分别占到各自乳粉中4种甾醇总量的40.9%～69.0%。结论此次检测的30批次婴儿配方乳粉中均含有一定量的植物甾醇,但样品中的甾醇含量不同。     

The presence of endotoxin in powdered infant formula milk and the influence of endotoxin and Enterobacter sakazakii on bacterial translocation in the infant rat

Lipopolysaccharide (LPS) is a heat stable endotoxin that persists during the processing of powdered infant formula milk (IFM). Upon ingestion it may increase the permeability of the neonatal intestinal epithelium and consequently bacterial translocation from the gut. To determine the level of endotoxin present in IFM, 75 samples were collected from seven countries (representing 31 brands) and analysed for endotoxin using the kinetic colorimetric Limulus amoebocyte lysate (LAL) assay. The endotoxin levels ranged from 40 to 5.5 x 10(4) endotoxin units (EU) per gram and did not correlate with the number of viable bacteria. The neonate rat model was used to address the risk of endotoxin-induced bacterial translocation from the gut. Purified Escherichia coli LPS was administered to rat pups followed by inoculation with Enterobacter sakazakii ATCC 12868. Bacteria were isolated from the mesentery, spleen, blood and cerebral spinal fluid (CSF) of endotoxin-treated rats due to enhanced gut and blood brain barrier penetration. Histological analysis of the colon showed marked distension of the mucosal and muscular layers. It is plausible that the risk of neonatal bacteraemia and endotoxemia, especially in neonates with immature innate immune systems, may be raised due to ingestion of IFM with high endotoxin levels.     

内蒙古地区婴幼儿配方乳粉中高氯酸盐与氯酸盐膳食暴露风险评估

目的 了解内蒙古地区婴幼儿配方乳粉中高氯酸盐和氯酸盐的污染水平,评估婴幼儿高氯酸盐和氯酸盐的膳食摄入风险,为指导内蒙古地区婴幼儿健康膳食提供科学依据。方法 采集内蒙古地区市售各段位的婴幼儿配方乳粉539份,乳粉冲调用水（冲调乳粉时可能使用的饮用水）254份,采用超高效液相色谱-串联质谱（UPLC-MS/MS）法对婴幼儿配方乳粉、乳粉冲调用水中的高氯酸盐和氯酸盐含量进行检测。以2015年中国婴幼儿食品消费量调查数据中内蒙古地区婴幼儿的消费量数据为依据,采用简单分布评估和累积暴露评估方法计算内蒙古地区婴幼儿配方乳粉中高氯酸盐和氯酸盐的膳食摄入风险。结果 婴幼儿配方乳粉中高氯酸盐的总体检出率为92.39%(498/539),检测值在未检出～89.30μg/kg,平均值为14.45μg/kg,中位数为9.00μg/kg;氯酸盐的总体检出率为73.10%(394/539),检测值在未检出～1 061.00μg/kg,平均值为93.25μg/kg,中位数为45.50μg/kg。乳粉冲调用水中高氯酸盐的总体检出率为67.32%(171/254),检测值在未检出～26.59μg/L,平均值为1.25μ...     

酶水解-阴离子色谱法联用测定婴幼儿配方奶粉中果聚糖的总含量及平均聚合度

摘 要：目的 建立酶水解—离子色谱法测定婴幼儿配方奶粉中总果聚糖的分析方法。方法 通过酶水解将样品中的果聚糖水解成果糖、葡萄糖,以PA1阴离子交换柱分离,脉冲积分安培检测器进行检测果聚糖总含量,以果糖与葡萄糖产生的比例计算平均聚合度。结果 果糖、葡萄糖在0.25~25.0 mg/L范围内线性关系良好（R2>0.999）,果聚糖的回收率为96.9%~104.4%,方法检出限为195mg/kg,定量限为650mg/kg。实际样品测定中,日间的相对标准偏差（RSD,n=6）为1.15%~3.87%。结论 可用于婴幼儿配方奶粉中果聚糖的总含量及平均聚合度的测定方法。     

Isolation of Enterobacter sakazakii and other Enterobacteriaceae from powdered infant formula milk and related products

The presence of Enterobacter sakazakii and other Enterobacteriaceae was surveyed in 82 powdered infant formula milk (IFM) and 404 other food products. The presence of Ent. sakazakii was detected using the conventional method (growth on violet red bile glucose agar plus yellow pigment production on TSA) and a new chromogenic medium (Druggan–Forsythe–Iversen agar, DFI) which enables results to be obtained 2 days earlier than the conventional method. Ent. sakazakii was isolated from 2/82 powdered IFM, 5/49 dried infant foods, 3/72 milk powder, 2/62 cheese products and various dry food ingredients, especially herbs and spices (40/122). Ent. sakazakii was isolated from 67 samples using the DFI medium, however only 19 of the samples were positive following the conventional method. The largest difference in isolation between the two methods was with dry food ingredients.Although Enterobacteriaceae were enumerated from one powdered IFM sample (Klebsiella ozaenae, 200 cfu/g), 7/82 had detectable Enterobacteriaceae after enrichment in EE broth. Using the ISO 6579 2002 method and immuno-magnetic separation technique no Salmonella serovars were isolated from powdered IFM, dried infant foods or milk samples. Therefore hygienic production of powdered IFM and milk production as monitored by control of Salmonella and enumeration of Enterobacteriaceae did not control Ent. sakazakii.     

婴幼儿配方乳粉中叶黄素的测定及其储存过程中损失率的研究

目的建立一种婴幼儿配方乳粉中叶黄素含量的测定方法。并确定叶黄素标准储备液的有效期和考察婴幼儿配方乳粉储存和食用过程中叶黄素含量的损失率。方法样品经超纯水溶解后以0.1%BHT-丙酮溶液超声提取。以甲醇-甲基叔丁基醚为流动相等度洗脱,流速为1.0 m L/min,进样量50μL,柱温25℃,二极管阵列检测器检测,检测波长445 nm。结果在15 min内完成目标物的分离分析,叶黄素在0.1、1.0、10.0μg/100g 3个浓度水平的回收率为90.0%~98.9%,相对标准偏差小于1.47%(n=6),方法定量限为0.5μg/100 g。叶黄素储备液在-70℃冰箱中保存12个月内含量稳定。结论该方法快速、准确、灵敏,适合测定婴幼儿配方乳粉中叶黄素含量的检测,婴幼儿配方乳粉在储存过程中叶黄素含量有下降趋势,保质期内符合国家标准要求。     

Changes in content of vitamins A and E in growing‐up milk throughout its shelf life

The stabilities of vitamins A and E were determined in 51 samples of growing‐up milk stored at 23, 30 and 37 °C for up to 9 months. Initially, the content of vitamin A and vitamin E was 330 RE μg/100 mL and 1.78 α‐TE mg/100 mL, respectively. Decreases in vitamin content were higher (P < 0.05) in formulas stored at 37 °C (from 330 to 111 μg RE/100 mL for vitamin A and from 1.78 to 1.16 mg α‐TE/100 mL for vitamin E). Over‐fortification of growing‐up milk could be recommended for vitamin E.     

扬州市售婴幼儿乳粉中蛋白质及三聚氰胺的分析与评价

通过抽样检测扬州各超市婴幼儿乳粉中蛋白质及三聚氰胺含量,对扬州市婴幼儿乳粉安全情况进行监控。所抽检婴幼儿配方乳粉严格按照国标方法进行检测。检测结果表明蛋白质含量未出现过低或过高现象,符合国标中对蛋白质含量的规定;三聚氰胺的含量均低于检测限0.05mg/kg,远低于卫生部规定的限量值1mg/kg。根据国家标准的检测方法和评价指标,所抽检的样品均合格,表明扬州市售的婴幼儿乳粉质量有保证,且监管工作卓有成效。     

A novel photoreactive DNA-binding dye for detecting viable Klebsiella pneumoniae in powdered infant formula

In addition to Cronobacter spp., Klebsiella pneumoniae is another opportunistic bacterial pathogen present in powdered infant formula (PIF) that can cause pneumonia, septicemia, and other diseases. In this study, a rapid and specific method based on a fluorescence probe was developed for detecting viable K. pneumoniae in PIF samples via the combination of recombinase-aided amplification (RAA) with thiazole orange monoazide (TOMA) dye (the TOMA–RAA assay hereafter). As a novel photosensitive DNA-intercalating dye, TOMA was used to penetrate bacterial cells, including both dead and viable cells, as verified by confocal laser scanning microscopy and fluorescent emission spectrometry. Importantly, the RAA assay exhibited good performance in detecting K. pneumoniae within 40 min at 39°C. Under optimal conditions, the TOMA–RAA assay can detect as low as 2.6 × 10³ cfu/mL of K. pneumoniae in pure culture and 2.3 × 10⁴ cfu/g of K. pneumoniae in spiked PIF sample. After 3 h of pre-enrichment, 3 × 10⁰ cfu/g of K. pneumoniae can be detected. Furthermore, the TOMA–RAA assay displayed an excellent anti-interference ability to nontarget bacteria. In short, the proposed method has great potential application for the rapid and accurate detection of viable K. pneumoniae in PIF.