Thermal Treatment Of Milk Research Articles

The Impact of Thermal Treatment Intensity on Proteins, Fatty Acids, Macro/Micro-Nutrients, Flavor, and Heating Markers of Milk-A Comprehensive Review.

Milk thermal treatment, such as pasteurization, high-temperature short-time processing, and the emerging ultra-short-time processing (<0.5 s), are crucial for ensuring milk safety and extending its shelf life. Milk is a nutritive food matrix with various macro/micro-nutrients and other constituents that are possibly affected by thermal treatment for reasons associated with processing strength. Therefore, understanding the relationship between heating strength and milk quality is vital for the dairy industry. This review summarizes the impact of thermal treatment strength on milk's nutritional and sensory properties, the synthesizing of the structural integrity and bioavailability of milk proteins, the profile and stability of fatty acids, the retention of macro/micro-nutrients, as well as the overall flavor profile. Additionally, it examines the formation of heat-induced markers, such as Maillard reaction products, lactulose, furosine, and alkaline phosphatase activity, which serve as indicators of heating intensity. Flavor and heating markers are commonly used to assess the quality of pasteurized milk. By examining former studies, we conclude that ultra-short-time-processing-treated milk is comparable to pasteurized milk in terms of specific parameters (such as whey protein behavior, furosine, and ALP contents). This review aims to better summarize how thermal treatments influence the milk matrix, guiding the dairy industry's development and balancing milk products' safety and nutritional value.

Assessment of the Microbiological Safety and Hygiene of Raw and Thermally Treated Milk Cheeses Marketed in Central Italy between 2013 and 2020.

A profile of the microbial safety and hygiene of cheese in central Italy was defined based on an analysis of 1373 cheeses sampled under the Italian National Control Plan for Food Safety spanning the years 2013 to 2020 and tested according to Commission Regulation (EC) No. 2073/2005 (as amended). A total of 97.4% of cheese samples were assessed as being satisfactory for food safety criteria and 80.5% for process hygiene criteria. Staphylococcal enterotoxin was found in 2/414 samples, while Salmonella spp. and Listeria monocytogenes were detected in 15 samples out of 373 and 437, respectively. Escherichia coli and coagulase-positive staphylococci counts were found unsatisfactory in 12/61 and 17/88 cheese samples, respectively. The impact of milking species, milk thermal treatment, and cheese hardness category was considered. A statistically significant association (p < 0.05) was found between milk thermal treatment and the prevalence of coagulase-positive staphylococci and Listeria monocytogenes and between hardness and unsatisfactory levels of Escherichia coli. The data depict a contained public health risk associated with these products and confirm, at the same time, the importance of strict compliance with good hygiene practices during milk and cheese production. These results can assist in bolstering risk analysis and providing insights for food safety decision making.

Biogenic Amine Content in Retailed Cheese Varieties Produced with Commercial Bacterial or Mold Cultures

Biogenic amines (BAs) are considered a potential microbiological toxicological hazard in aged cheese. Risk mitigation strategies include good hygiene practice measures, thermal treatment of milk and the use of competitive dairy cultures. The aim of this study was to evaluate the amount of BAs—tryptamine, β-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine and spermine—in the core and rind of cheeses ripened by bacteria (n = 61) and by mold cultures (n = 8). The microbial communities were counted, and the dominant lactic acid bacteria (LAB) were identified, corresponding to the BA concentrations. The total BA content was highest in the core of semi-hard cheeses (353.98 mg/kg), followed by mold cheeses (248.99 mg/kg) and lowest in hard cheeses (157.38 mg/kg). The highest amount of BAs was present in the rind of cheeses with mold (240.52 mg/kg), followed by semi-hard (174.99 mg/kg) and hard cheeses (107.21 mg/kg). Tyramine was the most abundant BA, represented by 75.4% in mold cheeses, 41.3% in hard cheese and 35% of total BAs in semi-hard cheeses. Histamine was present above the defined European maximum level (ML) of 100 mg/kg in only two semi-hard and three hard cheeses. High amount of BAs (above 600 mg/kg) in cheeses, mainly tyramine, were associated with the presence of Enterococcus durans, while negligible BA concentrations were found in cheeses ripened with Lacticaseibacillus rhamnosus, Lactococcus lactis or Lacticaseibacillus paracasei cultures. This study has shown that retailed cheese varieties produced with commercial bacterial or mold cultures have acceptable levels of biogenic amines with respect to consumers.

Lactose Glycation of the Maillard-Type Impairs the Benefits of Caseinate Digest to the Weaned Rats for Intestinal Morphology and Serum Biochemistry.

The Maillard reaction between the lactose and milk proteins unavoidably occurs during the thermal treatment of milk. Although the impact of this reaction on protein nutrition and safety has been well-studied, whether a lactose glycation of milk proteins of the Maillard-type might affect the rats in their growth and intestinal morphology needs an investigation. In this study, caseinate and lactose-glycated caseinate were digested using pepsin and trypsin. Afterward, the resultant caseinate digest and glycated caseinate digest (lactose content of 13.5 g/kg of protein) at 100, 200, and 400 mg/kg body weight (BW)/d were assessed for their effects on the female weaned Wistar rats in terms of daily body weight gain, intestinal morphology, digestive and brush-border enzyme activities, as well as serum chemical indices. The results showed that glycated caseinate digest always showed a weaker effect on rat than caseinate digest either at the 0–7 or 0–28 d feeding stage, and more importantly, at the highest dose of 400 mg/kg BW/d, it caused obvious adverse effect on the rats, reflected by lower values of these indices. Compared with caseinate digest, glycated caseinate digest in the rats caused 0.9–15.4% and 10.6–49.7% decreases in average daily gain of BW and small intestinal length, 1.1–21.5% and 2.3–33.3% decreases in villus height and the ratio of villus height to crypt depth of the small intestine, or 0.3–57.6% and 0.2–55.7% decreases in digestive and critical brush-border enzyme activities, respectively. In addition, when the rats were fed with glycated caseinate digest, some serum indices related to oxidative stress status were enhanced dose-dependently. Lactose glycation of the Maillard-type is thus considered as a negative event of the Maillard reaction on milk proteins because this reaction might impair protein benefits to the body.

Physical properties and storage stability of reverse osmosis skim milk concentrates: Effects of skim milk pasteurisation, solid content and thermal treatment

Concentrated dairy products are of increasing interest within the dairy industry. Skim milk concentrates can be produced by reverse osmosis membrane filtration, which can be considered a non-thermal process. Therefore, the physical properties of concentrates differ from the properties of concentrates produced by evaporation. In this study, reverse osmosis filtration of raw and pasteurised skim milk was carried out in batch up to 28% total solids content and the effect of thermal treatment (65–110 °C, 15 s) and storage at 5 °C up to ten days on rheological and physical properties of concentrates, were evaluated. Concentrates produced from pasteurised skim milk required longer concentration times and showed larger average casein micelle sizes, but limited structure build-up capability during storage compared to concentrates produced from raw milk which more readily created structural networks between the milk constituents and consequently had higher viscosity. Thermal treatment of concentrates increased their average particle size and viscosity, an effect enhanced by increasing the total solids content. Concentrates produced from non-pasteurised milk showed the strongest shear-thinning behaviour during storage. Thus, the thermal treatment of milk before or after the concentration process, controls the structure formation of skim milk concentrates during storage.

Thermal Effects on Biochemical Signatures of UHT, Pasteurized and Domestically Boiled Buffalo Milk Detected by Synchronous Fluorescence Spectroscopy.

Thermal treatment of milk is performed to limit bacterial growth and make it safe for human consumption. To increase the shelf life of milk, either ultrahigh temperature (UHT) or pasteurization techniques are employed that destroy the microorganisms. In this study, the synchronous front face fluorescence spectroscopy was employed for comparative study of raw, UHT treated, pasteurized and conventionally boiled milk at 93°C (domestic boiling). Principal Component analysis clearly showed distinct clustering of UHT milk due to formation of Maillard reaction products. Fluorescence emission peak at 410nm showed irreversible change in peak intensity attributed to conformational changes in protein due to UHT treatment while pasteurization and domestic boiling showed reversible changes when milk was cooled down to 10°C. Furthermore, fluorescence emission peaks at 410nm previously assigned to vitamin A has also been discussed.

Use of 31P NMR and FTIR to investigate key milk mineral equilibria and their interactions with micellar casein during heat treatment

The thermal treatment of milk is one of the key processes routinely performed in the dairy industry. Several modifications occur in milk during heating, particularly with respect to its mineral equilibrium. As the temperature increases, the solubility of calcium and phosphate decreases leading to precipitation in the casein micelle as casein phosphate nanocluster. Recently, 31P NMR and Fourier Transform Infrared have been demonstrated to be capable of monitoring changes to its nanocluster. In this study, the effect of temperature on nanocluster during heating of milk to temperatures ranging from 25 °C to 80 °C followed by subsequent cooling were studied. It was also demonstrated that key ionic components of the mineral equilibria behaved differently with temperature, e.g., calcium influence was evident only at lower temperature, while the opposite was the case with phosphate. It was also shown that micellar casein concentration was influential at all temperatures, most notably at lower values.

Protein carbonylation sites in bovine raw milk and processed milk products.

During thermal treatment of milk, proteins are oxidized, which may reduce the nutritional value of milk, abolish protein functions supporting human health, especially important for newborns, and yield potentially harmful products. The side chains of several amino acids can be oxidized to reactive carbonyls, which are often used to monitor oxidative stress in organisms. Here we mapped protein carbonylation sites in raw milk and different brands of pasteurized, ultra high temperature (UHT) treated milk, and infant formulas (IFs) after digesting the precipitated proteins with trypsin. Reactive carbonyls were derivatized with O-(biotinylcarbazoylmethyl)hydroxylamine to enrich the modified peptides by avidin-biotin affinity chromatography and analyze them by nanoRP-UPLC-ESI-MS. Overall, 53 unique carbonylated peptides (37 carbonylation sites, 15 proteins) were identified. Most carbonyls were derived from dicarbonyls (mainly glyoxal). The number of carbonylation sites increased with the harsher processing from raw milk (4) to pasteurized (16) and UHT milk (16) and to IF (24).

Whey Preparation Methods and Thermal Treatment of Milk Affect Recovery of Lactoferrin Using Ion-Exchange Chromatography

This study aims to determine the effect of whey preparation method and thermal treatment of milk on recovery of lactoferrin (Lf). Lf was isolated using cation-exchange chromatography from differently prepared wheys, differently heat-treated skim milks and whey powder. The content of Lf was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and enzyme-linked immunosorbent assay. Lf was more recovered from cheese whey than that from acid whey. The recovery of Lf from skim milk pasteurized at 62.7C for 30 min and at 71.7C for 15 s was significantly lower than that from unpasteurized skim milk (P < 0.05). The longer skim milk was heated at 71.7C, the less Lf was recovered. Lf was little recovered from commercial milk treated at 130C for 2 s and whey powder. These results suggest that recovery of Lf be apparently affected by whey preparation method and thermal treatment of milk. Practical Applications Lactoferrin (Lf), which is a minor component in milk, has been known to have various beneficial functions in human health. It may be isolated from whey, a by-product of cheese processing. In this study, it was investigated how much Lf was recovered from different types of wheys and differently heat-treated milks. The results of the study would provide useful information to the industry which is interested in isolation and application of Lf.

A CFD model as a tool to simulate β-lactoglobulin heat-induced denaturation and aggregation in a plate heat exchanger

During the pasteurization process, the thermal treatment of milk and its derivatives in plate heat exchangers is limited by protein fouling. The deposition mechanism onto the heat transfer surface involves the denaturation and aggregation of β-lactoglobulin. In this work, a 2-D CFD analysis was conducted to simulate locally the heat-induced protein denaturation mechanisms. Firstly, we present various intermediate validations of the ability of the numerical model to capture the hydrodynamics, by showing the similarity of CFD results and experimental data. Finally, the close agreement between the denaturation level obtained by CFD and that obtained experimentally indicates the ability of the numerical model adopted to simulate the chemical reaction. The analysis of the species present in the plate heat exchanger is related to the deposit mass distribution along the heat exchanger using CFD data. It has been shown that the unfolded species are deposit precursors and that the distribution of the deposit is correlated to this source.

Chagas Disease and Breast-feeding

Chagas disease (infection by the protozoan Trypanosoma cruzi) is a major parasitic disease of the Americas and one of the main neglected tropical diseases. Although various routes of transmission sre recognized, the risk for transmission of the infection through breast-feeding has not clearly been established. We reviewed the literature on transmission of T. cruzi through breast-feeding to provide breast-feeding mothers with Chagas disease with medical guidance. Although data from animal studies and human studies are scarce, we do not recommend that mothers with Chagas disease discontinue breast-feeding, unless they are experiencing the acute phase of the disease, reactivated disease resulting from immunosuppression, or bleeding nipples. In these cases, thermal treatment of milk before feeding the infant may be considered.

Influence of surface modification on the composition of a calcium phosphate-rich whey protein deposit in a plate heat exchanger

The unwanted formation of deposits during the thermal treatment of milk and milk products is an unresolved problem for the dairy industry. A method to reduce fouling on heat transfer surfaces is the defined modification of the energetic surface properties. However, an anti-fouling surface, approved for use in the food industry, easy to clean, that is resistant in operation, and stays effective over the lifetime of a plant is still a challenge. The present work aims to investigate the influence of diamond-like carbon (DLC, a-C:H) and Si-doped DLC (a-C:H:Si and a-C:H:Si:O) coatings with particular high mechanical hardness, wear resistance, and chemical inertness, against milk fouling. Experiments were conducted using a pilot-scale plate heat exchanger with a calcium phosphate-rich whey protein solution as model fluid. The results showed that surface modification directly affected the formation of deposits, their composition, as well as their adhesive strength. Lower protein content on DLC and SICAN (a-C:H:Si) and lower mineral deposition on SICAN were measured. Further analysis showed that original energetic properties were changing during several fouling and cleaning cycles. Furthermore, the electron–donor component (γ−) was the main differentiating factor determining the extension of fouling. A quadratic relationship between the deposit protein content respectively the final fouling resistance and γ− was found, suggesting an optimum value of γ− for which fouling is minimal. The results should lead to a better understanding of the fouling process and demonstrates the potential of the DLC coatings to enhance operational effectiveness.

Thermal inactivation and variability of γ-glutamyltransferase and α-l-fucosidase enzymatic activity in sheep milk

We present a study of the thermal inactivation and variation of activity of two enzymes in sheep milk: γ-glutamyltransferase and α-l-fucosidase. We find that the thermal treatment of milk causes inactivation of α-l-fucosidase between 57 °C and 68 °C, and γ-glutamyltransferase between 68 °C and 80 °C. In untreated sheep milk, the highest level of enzymatic activity (EA) for these two enzymes is in the pH range 5.5–6.0 and 8.0–8.5, respectively. Skimming treatment causes the loss of 35% of the activity of γ-glutamyltransferase. No differences in the EA were ascribable to the diets evaluated in this study. We observed EAs of α-l-fucosidase and γ-glutamyltransferase over the entire lactation cycle, noting that the EA of the former increased from 81 to 207 U mL−1 (average 159 ± 30 U mL−1) while the EA of the latter from 3.12 to 4.89 U mL−1 (average 3.83 ± 0.34 U mL−1). Relationships between both enzymes and selected milk parameters (lipids, proteins, lactose, urea and somatic cells) are highlighted by Principal Component Analysis.

Redox proteomics of fat globules unveils broad protein lactosylation and compositional changes in milk samples subjected to various technological procedures

The Maillard reaction between lactose and proteins occurs during thermal treatment of milk and lactosylated β-lactoglobulin, α-lactalbumin and caseins have widely been used to monitor the quality of dairy products. We recently demonstrated that a number of other whey milk proteins essential for nutrient delivery, defense against bacteria/virus and cellular proliferation become lactosylated during milk processing. The extent of their modification is associated with the harshness of product manufacturing. Since fat globule proteins are also highly important for the health-beneficial properties of milk, an evaluation of their lactosylation is crucial for a complete understanding of aliment nutritional characteristics. This is more important when milk is the unique dietary source, as in the infant diet. To this purpose, a sequential proteomic procedure involving an optimized milk fat globule (MFG) preparation/electrophoretic resolution, shot-gun analysis of gel portions for protein identification, selective trapping of lactosylated peptides by phenylboronate chromatography and their analysis by nanoLC-ESI-electron transfer dissociation (ETD) tandem MS was used for systematic characterization of fat globule proteins in milk samples subjected to various manufacturing procedures. Significant MFG protein compositional changes were observed between samples, highlighting the progressive adsorption of caseins and whey proteins on the fat globule surface as result of the technological process used. A significant lactosylation of MFG proteins was observed in ultra-high temperature sterilized and powdered for infant nutrition milk preparations, which well paralleled with the harshness of thermal treatment. Globally, this study allowed the identification of novel 157 non-redundant modification sites and 35 MFG proteins never reported so far as being lactosylated, in addition to the 153 ones ascertained here as present on other 21 MFG-adsorbed proteins whose nature was already characterized. Novel MFG proteins include components involved in nutrient delivery, defense response against pathogens and cellular proliferation/differentiation. Nutritional, biological and toxicological consequences of these findings are here discussed, highlighting their possible impact on children's diet.

Transcriptome profiling of lactococcal mixed culture activity in milk by fluorescent RNA arbitrarily primed-PCR

Thermal treatment of milk is widely used to reduce milk contamination, while CO2 can be used to prevent bacterial growth and maintain milk quality during storage. These treatments applied before or during cheese manufacture could alter the metabolic activity of starter cultures. Changes in gene expression can be evaluated by differential display methods, so that effects on bacterial metabolic activity can be estimated by variation in transcription profiles. The aim of this study was to develop fluorescent RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) as a method to evaluate the influence of milk CO2 acidification as well as rennet and salt concentrations on starter gene expression. Comparison with reference conditions showed that gene transcription was influenced according to the extent of thermal treatment as well as by CO2 acidification followed by different neutralization procedures. Thus, simple acid neutralization after CO2 acidification was not sufficient to regain the reference transcriptome profile. Starter gene transcription profiles showed important modifications following an increase in NaCl concentration or a decrease in rennet activity from standard conditions used in Cheddar cheese making. Increasing rennet activity results in small changes in the starter RNA profile. Fluorescent RAP-PCR is a promising method for obtaining a better understanding of gene expression profiles of mixed cultures during cheese making.

Conjugated linoleic acid and C18:1 isomers content in milk fat of sheep and their transfer to Pecorino Toscano cheese

The aim of the study was to evaluate the transfer of conjugated linoleic acid (CLA) and of C18:1 isomers from sheep milk to Pecorino Toscano protected denomination of origin cheese and to monitor the stability of these fatty acids during ripening. The total content of C18:1 fatty acids was not affected by milk treatment but there were changes in the isomers profile. In particular, the milk trans11 C18:1 decreased with pasteurization and after starter culture addition. In contrast, trans10 C18:1 and cis9, trans11 C18:2 were enhanced by the thermal treatment of milk. The fatty acid profile of cheese reflected that of milk used for cheese making with the exception of the C18:1 and CLA isomer profile. The cheese ripening affected the percentage of cis9, trans11 C18:2, which increased more than 10% on total content of CLA.

Evaluation of amino acid-decarboxylative microbiota throughout the ripening of an Italian PDO cheese produced using different manufacturing practices

To investigate the presence of biogenic amines (BAs) in Montasio cheese produced by using different cheese manufacturing practices. Three batches of Montasio cheese were made in the following way: batch A using raw milk and natural milk culture, batch B with thermized milk and natural milk culture and batch C with thermized milk and natural milk culture added of a commercial starter culture. During 120 days of ripening analyses were performed for microbial counts and BA content; indeed, the potential to produce BAs was screened in lactic acid bacteria and Enterobacteriaceae isolates. At the end of ripening, the total BA contents of cheeses from batches A, B and C were 166.3, 207.3 and 29.8 mg kg(-1), respectively. Amino acid decarboxylase activity was widespread among isolates. The BA content of Montasio cheese from the three batches was below the threshold proposed as potentially toxic. The highest BA content was found in cheese produced using thermized milk and natural milk culture; therefore, the thermal treatment of milk was not enough by itself to reduce the counts of decarboxylase-positive bacteria in cheese. The use of selected starters guaranteed a low BA content in Montasio cheese. The study of the effects of some technological processes on the incidence of decarboxylative microbiota in 'protected denomination of origin' cheeses could provide useful information on the hygienic risk related to their production.

Safety Evaluation of an Oak-Flavored Milk Powder Containing Ellagitannins upon Oral Administration in the Rat

Ellagitannins are phenolic compounds that occur in a number of dietary sources such as walnuts, raspberries, pomegranate, strawberries, and oak-aged wines. Ellagitannins have been acknowledged to have antioxidant and cancer chemopreventive activities. However, ellagitannins have also been considered to be "antinutrients" and have been reported to provoke adverse effects in animals. In this context, risk assessment studies are demanded to ensure that chemicals present in food do not compromise food safety. Oak-flavored milk can be obtained by thermal treatment of milk in the presence of oak shavings. The oak-flavored milk can be used to impart wood-like flavor to different recipes. The present study evaluated, under a subchronic approach, the safety of an oak-flavored milk powder containing ellagitannins in rats upon repeated oral administration for 96 days. The effect of 30% oak-flavored milk powder in the diet was evaluated. This amount involved a margin of safety equivalent to the daily intake of 134 yogurts by a 70 kg person for 96 days. Growth rate, food utility index, 9 hematological, and 13 serobiochemical parameters as well as the metabolism and tissue distribution of ellagitannins and derived metabolites were studied. Overall, no significant differences were found in oak-milk-fed rats in any blood parameter analyzed. No effect was found on growth rate and food utility index. Urolithin A was identified in feces of rats fed oak-flavored milk and the glucuronide derivative in urine. No metabolites were found in the liver, kidney, or uterus. Histopathological analysis of liver and kidney corroborated the absence of toxicity. Therefore, these results suggest that the intake of the oak-flavored milk powder assayed in this study is safe and does not involve potential hazard to human health.

Characterization of heat-induced lactosylation products in caseins by immunoenzymatic and mass spectrometric methodologies

Nonenzymatic glycosylation of proteins occur during milk thermal treatment through the Maillard reaction. Immunoenzymatic and spectrometric methodologies were used to investigate caseins modification in samples submitted to different processing. As expected, protein-bound carbonyl content in raw and thermal-treated milks was positively correlated with the severity of the treatment. When immunoblotting and ELISA experiments were carried out either on isolated or whole milk proteins, carbonyl accumulation on caseins and macromolecular aggregates produced by thermal processing was evidenced. A comparative electrospray-mass spectrometry (ES-MS) analysis of different milks allowed verifying the extent of Amadori adducts on the more abundant protein components (αs 1- and β-casein (αs 1- and β-CN)). A combined matrix-assisted laser desorption ionization (MALDI)-MS/Edman degradation approach on enzymatic digests identified caseins modification sites. In moderately heat-treated milks, we observed that lactosylation occurred specifically at Lys-34 (αs 1-CN) and Lys-107 (β-CN); whereas, samples subjected to more severe conditions presented modification at Lys-7, Lys-34, Lys-83, Lys-103, Lys-105, Lys-132 and Lys-193 (αs 1-CN) and at Lys-32, Lys-48, Lys-107, Lys-113 and Lys-176 (β-CN). Differences in secondary structure of these components was assayed by circular dichroism (CD) spectroscopy.

Nucleosides and nucleotides: natural bioactive substances in milk and colostrum

Nucleotides, nucleosides and nucleobases belong to the non-protein-nitrogen (NPN) fraction of milk. The largest amounts of ribonucleosides and ribonucleotides--ribose forms only were considered in this review--were measured directly after parturition in bovine milk and other ruminants as well as in the milk of humans. Generally, concentrations of most of the nucleos(t)ides tend to decrease gradually with advancing lactation period or nursing time. The species-specific pattern of these minor constituents in milk from different mammals is a remarkable property and confirms, at least, the specific physiological impact of these minor compounds in early life. The physiological capacity of these compounds in milk is given by the total potentially available nucleosides. The main dietary sources of nucleos(t)ides are nucleoproteins and nucleic acids which are converted in the course of intestinal digestion into nucleosides and nucleobases the preferred forms for absorption in the intestine. Thus, nucleosides and nucleobases are suggested to be the acting components of dietary and/or supplemented nucleic acid-related compounds in the gut. They are used by the body as exogenous trophochemical sources and can be important for optimal metabolic functions. Up to 15 % of the total daily need for a breast-fed infant was calculated to come from this dietary source. Concerning their biological role they not only act as metabolites but are also involved as bioactive substances in the regulation of body functions. Dietary nucleotides affect immune modulation, e.g. they enhance antibody responses of infants as shown by a study with more than 300 full-term healthy infants. Dietary nucleos(t)ides are found to contribute to iron absorption in the gut and to influence desaturation and elongation rates in fatty acid synthesis, in particular long-chain polyunsaturated fatty acids in early stages of life. The in vitro modulation of cell proliferation and apoptosis has been described by ribonucleosides, in particular by modified components using human cell culture models. Due to the bio- and trophochemical properties of dietary nucleos(t)ides, the European Commission has allowed the use of supplementation with specific ribonucleotides in the manufacture of infant and follow-on formula. From the technochemical point of view, the ribonucleoside pattern is influenced by thermal treatment of milk. In addition ribonucleosides are useful indicators for quantifying adulterations of milk and milk products.