This study aimed to elucidate the effects of various nutritional supplements on the physical, structural and sensory attributes of low-fat yogurt derived from camel milk, with the longer-term objective of enhancing its appeal and suitability for elderly consumers. Fresh camel milk was obtained from an Australian farm. Two yogurt variants were created: plain yogurt (CMY) and yogurt with added fructooligosaccharides, microbial transglutaminase (a ubiquitous food additive with potential health risks), apple pectin and linseed oil (CMYWA). The syneresis index of these yogurts was quantified through centrifugation, colour changes due to additives were assessed via colorimetric methods and both viscosity and granulometry were determined using precise instrumental techniques. After 7 d refrigerated storage, syneresis was 50% in CMY vs. 30% in CMYWA. Viscosity on day 7 was 205 mPa.s for CMYWA vs. 110 mPa.s for CMY. The CMYWA granule size increased from 2.1 μm on day 0 to 2.8 μm on day 14, while CMY granule size remained stable around 1.9 μm. Lactobacilli counts were higher in CMYWA at 2.8 × 107 CFU/g vs. 2.3 × 106 CFU/g in CMY. In a paired preference test with 37 consumers aged 18–65, CMYWA was significantly preferred over CMY. Sensory evaluations further substantiated that the yogurts with added supplements were more appealing to the palate. The results demonstrate the supplements improved camel milk yogurt properties.

This study aimed to review hazard analysis and critical control points (HACCP) in the dairy industry for the production of yogurt. The food safety management system (FSMS) was implemented over the last several decades with several amendments. The need for practical and proactive procedures in the dairy industry was identified so that HACCP implementation could ensure that consumers would always have safe food. The concept of HACCP is a systemic and science-based method that can result in safe dairy products such as yogurt based on the complete analysis of manufacturing processes, recognition of hazards potentially present at all stages of production, and risk prevention. In yogurt production, raw milk receipt, pasteurization, packaging, and storage are the steps most susceptible to contamination and were considered critical control points. Further steps also need to be implemented to achieve other related control measures, and these will be discussed.

Consumption of probiotics and/or yogurt could be a solution for restoring the balance of the gut microbiota. This study examined associations of regular intake of probiotic supplements or yogurt with the gut microbiota among a diverse population of older adults (N=1,861; 60–72 years). Faecal microbial composition was obtained from 16S rRNA gene sequencing (V1–V3 region). General linear models were used to estimate the associations of probiotic supplement or yogurt intake with microbiome measures adjusting for covariates. Compared to non-yogurt consumers (N=1,023), regular yogurt consumers (≥once/week, N=818) had greater Streptococcus (β=0.29, P=0.0003) and lower Odoribacter (β=−0.33, P<0.0001) abundance. The directions of the above associations were consistent across the five ethnic groups but stronger among Japanese Americans (Streptococcus: β=0.56, P=0.0009; Odoribacter: β=−0.62, P=0.0005). Regular intake of probiotic supplements (N=175) was not associated with microbial characteristics (i.e., alpha diversity and the abundance of 152 bacteria genera). Streptococcus is one of the predominant bacteria genera in yogurt products, which may explain the positive association between yogurt consumption and Streptococcus abundance. Our analyses suggest that changes in Odoribacter were independent of changes in Streptococcus abundance. Future studies may investigate whether these microbial genera and their sub-level species mediate potential pathways between yogurt consumption and health.

Dairy product intake was suggested to reduce the risk of gastrointestinal cancers. This study investigated the association between dairy product intake and the risk of pancreatic cancer (PAC) using a prospective cohort study and meta-analysis of prospective cohort studies. First, we included 59 774 people aged 40–79 years from the Japan Collaborative Cohort Study (JACC Study). The Cox regression was used to compute the hazard ratios (HR) and 95 % CI of incident PAC for individuals who reported the highest intakes of milk, cheese and yogurt compared with not consuming the corresponding dairy products. Then, we combined our results with those from other four prospective cohort studies that were eligible after searching several databases, in a meta-analysis, using the fixed-effects model before evaluating publication bias and heterogeneity across studies. In the JACC Study, the highest v. no intakes of milk, cheese and yogurt were not associated with the reduced risk of PAC after a median follow-up of 13·4 years: HR (95 % CI) = 0·93 (0·64, 1·33), 0·91 (0·51, 1·62) and 0·68 (0·38, 1·21), respectively. The results did not significantly change in the meta-analysis: 0·95 (0·82, 1·11) for milk, 1·16 (0·87, 1·55) for cheese and 0·91 (0·79, 1·05) for yogurt. The meta-analysis showed no signs of publication bias or heterogeneity across studies. To conclude, consumption of milk, cheese and yogurt was not associated with the risk of PAC either in the JACC Study or the meta-analysis.

Little is known on the association between frequency of yogurt consumption and dietary intake in the United Kingdom (UK). The aim of the present study was to examine associations between frequency of yogurt consumption and dietary outcomes in children (n 1912, age 9⋅6 ± 0⋅1 years, 51 % boys) and adults (n 2064, age 48⋅7 ± 0⋅5 years, 49 % men) using cross-sectional data from the National Diet and Nutrition Survey rolling programme year 7 to year 9 (2014/15–2016/17). The frequency of yogurt consumption was determined by the number of days with yogurt reported in 4-d food diaries and participants were classified as non-eaters, occasional eaters (1–2 d of consumption) or regular eaters (3–4 d of consumption). Dietary outcomes were estimated from food diaries. The frequency of yogurt consumption was positively associated with intake of key vitamins and minerals such as thiamin, riboflavin, vitamin C, potassium, calcium, magnesium, phosphorus and iodine in both children and adults (all P < 0⋅0018), as well as higher intake of total dairy (P < 0⋅0001 for both children and adults). Regular yogurt eaters were more likely to meet or exceed nutrient recommendations for vitamins and minerals such as vitamin A, riboflavin, folate, potassium, calcium, magnesium, zinc and iodine (all P < 0⋅001). Diet quality was positively associated with frequency of yogurt consumption in children (P = 0⋅045) and adults (P < 0⋅001). No association between yogurt consumption and free sugar intake was found (P = 0⋅49 for children and P = 0⋅29 for adults). The study suggests that frequency of yogurt consumption is associated with better dietary intake and diet quality in children and adults in the UK.

The aim of this review was to present various topics related to lactose intolerance with special attention given to the role of fermented foods and probiotics in alleviating gastrointestinal symptoms. Lactose intolerance is a common digestive problem in which the human body is unable to digest lactose, known as milk sugar. Lactose intolerance can either be hereditary or a consequence of intestinal diseases. Recent work has demonstrated that fermented dairy products and probiotics can modify the metabolic activities of colonic microbiota and may alleviate the symptoms of lactose intolerance. We suggest that, lactose free dairy products could be recommended as alternatives for the alleviation of lactose intolerance and for the promotion of human health and wellness.

In France, dairy products contribute to dietary saturated fat intake, of which reduced consumption is often recommended for CVD prevention. Epidemiological evidence on the association between dairy consumption and CVD risk remains unclear, suggesting either null or inverse associations. This study aimed to investigate the associations between dairy consumption (overall and specific foods) and CVD risk in a large cohort of French adults. This prospective analysis included participants aged ≥18 years from the NutriNet-Santé cohort (2009–2019). Daily dietary intakes were collected using 24-h dietary records. Total dairy, milk, cheese, yogurts, fermented and reduced-fat dairy intakes were investigated. CVD cases (n 1952) included cerebrovascular disease (n 878 cases) and CHD (n 1219 cases). Multivariable Cox models were performed to investigate associations. This analysis included 104 805 French adults (mean age at baseline 42·8 (sd 14·6) years, mean follow-up 5·5 (sd 3·0) years, i.e. 579 155 person-years). There were no significant associations between dairy intakes and total CVD or CHD risks. However, the consumption of at least 160 g/d of fermented dairy (e.g. cheese and yogurts) was associated with a reduced risk of cerebrovascular diseases compared with intakes below 57 g/d (hazard ratio = 0·81 (95 % CI 0·66, 0·98), Ptrend = 0·01). Despite being a major dietary source of saturated fats, dairy consumption was not associated with CVD or CHD risks in this study. However, fermented dairy was associated with a lower cerebrovascular disease risk. Robust randomised controlled trials are needed to further assess the impact of consuming different dairy foods on CVD risk and potential underlying mechanisms.

Consumer willingness to pay (WTP) for yogurt attributes was evaluated using a survey targeted to be nationally representative within the United States. A novel approach was used to allow for self-selection into the choice experiment for commonly purchased types of yogurt, either Greek or traditional, based on what consumers purchase. They were willing to pay a positive amount for requiring pasture access and not permitting dehorning/disbudding (which references the removal of horns or horn buds) for both traditional and Greek yogurt. Respondents had positive WTP for Greek yogurt labeled free of high-fructose corn syrup and a higher WTP for low-fat yogurt when compared to nonfat for both yogurt types.

Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case–control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case–case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.

Evidence from randomised controlled trials supports beneficial effects of total dairy products on body weight, fat and lean mass, but evidence on associations of dairy types with distributions of body fat and lean mass is limited. We aimed to investigate associations of total and different types of dairy products with markers of adiposity, and body fat and lean mass distribution. We evaluated cross-sectional data from 12 065 adults aged 30–65 years recruited to the Fenland Study between 2005 and 2015 in Cambridgeshire, UK. Diet was assessed with an FFQ. We estimated regression coefficients (or percentage differences) and their 95 % CI using multiple linear regression models. The medians of milk, yogurt and cheese consumption were 293 (interquartile range (IQR) 146–439), 35·3 (IQR 8·8–71·8) and 14·6 (IQR 4·8–26·9) g/d, respectively. Low-fat dairy consumption was inversely associated with visceral:subcutaneous fat ratio estimated with dual-energy X-ray absorptiometry (–2·58 % (95 % CI –3·91, –1·23 %) per serving/d). Habitual consumption per serving/d (200 g) of milk was associated with 0·33 (95 % CI 0·19, 0·46) kg higher lean mass. Other associations were not significant after false discovery correction. Our findings suggest that the influence of milk consumption on lean mass and of low-fat dairy consumption on fat mass distribution may be potential pathways for the link between dairy consumption and metabolic risk. Our cross-sectional findings warrant further research in prospective and experimental studies in diverse populations.

A commercial drinkable yogurt with and without 4% of added trehalose (as cell protectant) was spray-dried obtaining a powder with low water activity (aw). Total bacterial count in the powder was between 8.48–8.90 log cfu/g. The dried yogurt was stored: (i) at 38 °C and aw = 0.33; (ii) at 38 °C in hermetically sealed flasks (aw = 0.21/0.22); (iii) in a cyclic temperature chamber (10–20 °C) in hermetically sealed flasks (aw = 0.21/0.22). Whole milk was then fermented by adding an inoculum of spray-dried yogurt after storage under these different conditions. The kinetics of acidification showed the presence of a lag time which was strongly dependent on storage conditions. The data was fitted with a logistic type equation from which the lag time was calculated. To evaluate structural differences among samples, Fourier Transform Infrared spectra (FTIR) were recorded. Partial Least Squares (PLS) models enabled a good correlation between lag time of fermentation and FTIR spectra. The lag time for yogurt powder stored at aw about 0.21/0.22 and cyclic temperature 10–20 °C remained approximately constant over the 12 weeks of storage, while all the other conditions resulted in a dramatic increase. The addition of trehalose had a small influence on lag time and, therefore, as a protectant of lactobacilli.

In this study, the relationship between the dissociation of κ-casein from casein micelles due to heat-induced denaturation and the strength of acid milk gel was investigated. The κ-casein-dissociated micelles were fractionated by gel filtration chromatography and two-dimensional polyacrylamide gel electrophoresis, and their zeta potential and surface hydrophobicity were measured. The negative charge of the κ-casein-dissociated micelles was lower than that of native micelles, and micellar surface hydrophobicity was higher. For confirmation, the isoelectric point of the casein micelles was measured. The κ-casein-dissociated micelles were found to cohere at an earlier stage of acidification than the native micelles. These results demonstrated that the heat-induced increase in the strength of acid milk gel was partly due to the decrease in micellar surface charge and partly to the increase in surface hydrophobicity caused by the dissociation of κ-casein.

The absence of a dedicated transport for disaccharides in the intestine implicates that the metabolic use of dietary lactose relies on its prior hydrolysis at the intestinal brush border. Consequently, lactose in blood or urine has mostly been associated with specific cases in which the gastrointestinal barrier is damaged. On the other hand, lactose appears in the blood of lactating women and has been detected in the blood and urine of healthy men, indicating that the presence of lactose in the circulation of healthy subjects is not incompatible with normal physiology. In this cross-over study we have characterised the postprandial kinetics of lactose, and its major constituent, galactose, in the serum of fourteen healthy men who consumed a unique dose of 800 g milk or yogurt. Genetic testing for lactase persistence and microbiota profiling of the subjects were also performed. Data revealed that lactose does appear in serum after dairy intake, although with delayed kinetics compared with galactose. Median serum concentrations of approximately 0·02 mmol/l lactose and approximately 0·2 mmol/l galactose were observed after the ingestion of milk and yogurt respectively. The serum concentrations of lactose were inversely correlated with the concentrations of galactose, and the variability observed between the subjects’ responses could not be explained by the presence of the lactase persistence allele. Finally, lactose levels have been associated with the abundance of the Veillonella genus in faecal microbiota. The measurement of systemic lactose following dietary intake could provide information about lactose metabolism and nutrient transport processes under normal or pathological conditions.

The aim of this study was to investigate the associations for specified substitutions between different subgroups of dairy products and the risk of type 2 diabetes. We used data from the Danish Diet, Cancer and Health cohort including 54 277 men and women aged 50–64 years at baseline. Information regarding intake of dairy products was obtained from a validated FFQ, and cases of type 2 diabetes were identified through the Danish National Diabetes Register. Cox proportional hazards regressions were used to estimate associations. During a median follow-up of 15·3 years, 7137 cases were identified. Low-fat yogurt products in place of whole-fat yogurt products were associated with a higher rate of type 2 diabetes (hazard ratio (HR) 1·17; 95 % CI 1·06, 1·29) per serving/d substituted. Whole-fat yogurt products in place of low-fat milk, whole-fat milk or buttermilk were associated with a lower rate of type 2 diabetes (HR 0·89; 95 % CI 0·83, 0·96; HR 0·89; 95 % CI 0·82, 0·96; HR 0·89; 95 % CI 0·81, 0·97; per serving/d substituted, respectively). The pattern of associations was similar when intake was expressed as kJ/d (kcal/d). These findings suggest that intake of whole-fat yogurt products in place of low-fat yogurt products, low-fat milk, whole-fat milk and buttermilk are associated with a lower rate of type 2 diabetes.

This cohort study examined the association between total and individual dairy products and the risk of developing the metabolic syndrome (MetS) and its components in Korean adults from the Korean Genome and Epidemiology Study. We prospectively analysed 5510 participants aged 40–69 years without the MetS at baseline during a 10-year follow-up period. Dairy consumption was assessed with a semi-quantitative FFQ at baseline and after 4 years. The MetS was defined according to the criteria by the National Cholesterol Education Program Adult Treatment Panel III. The Cox’s proportional hazard model was used to examine the association between consumption of total dairy products, milk and yogurt in servings per week and the risk of incident MetS or individual components. A total of 2103 subjects developed the MetS (38·2 %) during an average follow-up of 67·4 months (range 17–104 months). Frequent dairy consumption (>7 servings of total dairy and milk/week, ≥4 servings of yogurt/week) was associated with a reduced risk of incident MetS and its components. In the multivariable adjusted model, hazard ratios for the MetS were 0·51 (95 % CI 0·43, 0·61) for total dairy products, 0·50 (95 % CI 0·38, 0·66) for milk and 0·67 (95 % CI 0·57, 0·78) for yogurt in frequent consumers compared with non-consumers. An inverse association between milk/yogurt and low HDL-cholesterol was shown only in women. In conclusion, high consumption of individual dairy products including milk and yogurt as well as total dairy were associated with a reduced risk of incident MetS and individual components in Korean adults.

Probiotic-based starter cultures are generally used to produce fermented milks with improved characteristics in the final product. In this study, Lactobacillus casei and Streptococcus thermophilus (Lc1-St) were used as the starter inoculum. The transformation kinetics and properties of the final product were compared with systems produced with other inocula. The Lc1-St inoculum delayed the production of lactic acid from 40 to 70 min (depending on temperature and concentration) when compared to Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus (Lb-St) and Lactobacillus johnsonii and Streptococcus thermophilus (La1-St). The Lc1-St inoculum reached the aggregation system faster (30–80 min) than Lb-St (120–210 min) and La1-St (160–220 min), however, the production of exopolysaccharides and organic phosphates was delayed as a consequence of the lack of synergy between Lc1 and St.

Increasing feelings of satiety may reduce appetite and energy intake. The role of inulin consumption in impacting satiety is unclear. A randomised double-blind controlled crossover trial aimed to determine the effects of inulin+yogurt on satiety after 1 and 8-d consumption. The preload breakfast included 100 g vanilla yogurt with (yogurt-inulin (YI)) and without (yogurt-control (YC)) 6 g inulin. A total of nineteen healthy females (22·8 (sd 2·7) years) with non-restrained eating behaviour and taking hormonal contraceptives participated in the study. Day 1 and 8 visual analogue scale (VAS) ratings of Hunger, Fullness, Desire to Eat and Prospective Food Consumption (PFC) were collected at fasting and every 30 min for 180 min. Energy intake was calculated from a weighed ad libitum lunch and remainder of day food records. Total AUC was calculated for each VAS. Day 1 (VAS only) and 8 (VAS and energy intakes) data were compared between YI and YC using ANCOVA, and ANOVA was used to compare energy intakes on Day 1. There were no significant differences between Day 1 YI and YC AUC appetite ratings or energy intakes. However, 8-d consumption of YI v. YC was associated with lower Desire to Eat and PFC ratings but similar lunch and total day energy intakes. Therefore, the addition of 6 g inulin to a commercially available yogurt affected feelings of appetite, but not energy intake, after repeated consumption. These results suggest that inulin may be a suitable ingredient to increase dietary fibre consumption, with potential to impact appetite.

Yogurts are important dairy products that have known a rapid market growth over the past few decades. Industrial yogurt manufacture involves different processing steps. Among them, protein fortification of the milk base is elemental. It greatly enhances yogurt nutritional and functional properties and prevents syneresis, an undesirable yogurt textural defect. Protein enrichment can be achieved by either concentration process (evaporation under vacuum and membrane processing: reverse osmosis and/or ultrafiltration) or by addition of dairy ingredients. Traditionally, skim milk powder (SMP) is used to enrich the milk base before fermentation. However, increased quality and availability of other dairy ingredients such as milk protein isolates (MPI), milk protein concentrates (MPC) whey protein isolates (WPI) and concentrates (WPC), micellar casein (MC) and caseinates have promoted their use as alternatives to SMP. Substituting different dry ingredients for skim milk powder in yogurt making affects the yogurt mix protein composition and subsequent textural and sensorial properties. This review focuses on various type of milk protein used for fortification purposes and their influence on these properties.

Protein fortification and solubilisation into the milk base are important parameters enhancing yogurt texture. In this study, the milk base prepared from reconstituted skim milk powder was fortified with 2% of ‘aged’ (1 year old) or ‘fresh’ micellar casein (MC) powder. Micellar casein powders were left to rehydrate at 20°C for different times (5 or 180, 300, 480, 900 or 1440 min) before acidification with glucono-delta-lactone. The rehydration of the MC powders into milk was monitored with a granulo-morphometer equipment, thus, for the first time, allowing the elucidation of MC rehydration process into an opaque environment such as milk. Whereas the gel point was delayed proportionally to the powder rehydration length, the storage modulus appears unaffected. Besides, the gelation onset was not altered by the powder age.