Yogurt Production

Genetic diversity and phylogenetic relationships of Streptococcus thermophilus isolates from traditional Turkish yogurt: multilocus sequence typing (MLST)

Yogurt, a globally consumed fermented dairy product, is recognized for its taste and potential health benefits attributed to probiotic bacteria, particularly Streptococcus thermophilus. In this study, we employed Multilocus Sequence Typing (MLST) to investigate the genetic diversity and phylogenetic relationships of 13 S. thermophilus isolates from traditional Turkish yogurt samples. We also assessed potential correlations between genetic traits and geographic origins. The isolates were identified as S. thermophilus using VITEK® MALDI-TOF MS, ribotyping, and 16S rRNA analysis methods. MLST analysis revealed 13 different sequence types (STs), with seven new STs for Turkey. The most prevalent STs were ST/83 (n = 3), ST/135 (n = 2), and ST/134 (n = 2). eBURST analysis showed that these isolates mainly were singletons (n = 7) defined as sequence types (STs) that cannot be assigned to any group and differ at two or more alleles from every other ST in the sample. This information suggests that the isolates under study were genetically distinct from the other isolates in the dataset, highlighting their unique genetic profiles within the population. Genetic diversity analysis of ten housekeeping genes revealed polymorphism, with some genes showing higher allelic variation than others. Tajima's D values suggested that selection pressures differed among these genes, with some being more conserved, likely due to their vital functions. Phylogenetic analysis revealed distinct genetic diversity between Turkish isolates and European and Asian counterparts. These findings demonstrate the genetic diversity of S. thermophilus isolates in Turkish yogurt and highlight their unique evolutionary patterns. This research contributes to our understanding of local microbial diversity associated with yogurt production in Turkey and holds the potential for identifyic strains with enhanced functional attributes.

Exploitation of microbial activities at low pH to enhance planetary health

Awareness is growing that human health cannot be considered in isolation but is inextricably woven with the health of the environment in which we live. It is, however, under-recognized that the sustainability of human activities strongly relies on preserving the equilibrium of the microbial communities living in/on/around us. Microbial metabolic activities are instrumental for production, functionalization, processing, and preservation of food. For circular economy, microbial metabolism would be exploited to produce building blocks for the chemical industry, to achieve effective crop protection, agri-food waste revalorization, or biofuel production, as well as in bioremediation and bioaugmentation of contaminated areas. Low pH is undoubtedly a key physical-chemical parameter that needs to be considered for exploiting the powerful microbial metabolic arsenal. Deviation from optimal pH conditions has profound effects on shaping the microbial communities responsible for carrying out essential processes. Furthermore, novel strategies to combat contaminations and infections by pathogens rely on microbial-derived acidic molecules that suppress/inhibit their growth. Herein, we present the state-of-the-art of the knowledge on the impact of acidic pH in many applied areas and how this knowledge can guide us to use the immense arsenal of microbial metabolic activities for their more impactful exploitation in a Planetary Health perspective.

Effects of Polygonatum sibiricum on Physicochemical Properties, Biological Compounds, and Functionality of Fermented Soymilk

The purpose of this study was to investigate the effects of Polygonatum sibiricum (P. sibiricum) on microbial fermentation, physicochemical properties, and functional properties of fermented soymilk. Three types of fermented soymilk were prepared. The first type was fermented directly from regular soymilk (fermented soymilk, FSM), and the other two were fermented after adding P. sibiricum (P. sibiricum fermented soymilk, P-FSM) or P. sibiricum polysaccharides (P. sibiricum polysaccharides fermented soymilk, PP-FSM). The differences in physical and chemical indexes such as pH value, acidity, and water-holding capacity were mainly compared, and the differences in the contents of functional components such as total phenols, total flavonoids, soy isoflavones, γ-aminobutyric acid, and organic acids were compared. The functionalities of the three samples in terms of antioxidant activity were evaluated, and the relevance of each active substance was explored. Compared with the FSM group, the addition of P. sibiricum and P. sibiricum polysaccharides could not only significantly promote the fermentation of Lactobacillus but also significantly improve the stability of the finished products during storage and prolong the shelf life of the finished product. The conversion rates of glycoside soybean isoflavones in the PP-FSM and P-FSM groups were 73% and 69%, respectively, which were significantly higher than those in the FSM group (64%). At the end of fermentation, the γ-aminobutyric acid contents of the PP-FSM and P-FSM groups were 383.66 ± 1.41 mg/L and 386.27 ± 3.43 mg/L, respectively, while that of the FSM group was only 288.66 ± 3.94 mg/L. There were also great differences in the content and types of organic acids among the three samples, especially lactic acid and acetic acid. By comparing the antioxidant capacity of DPPH (1,1-Diphenyl-2-picrylhydrazyl free radical), AB-TS (2,2'-Azinobis-3-ethylbenzthiazoline-6-sulphonate), and iron chelation, it was found that both PP-FSM and P-FSM were superior to FSM, and the antioxidant capacity had a certain correlation with the contents of total phenols and total flavonoids.

A comprehensive review on yogurt syneresis: effect of processing conditions and added additives

Yogurt, produced by the lactic fermentation of milk base, is an important dairy product worldwide. One of the essential sensory properties of yogurt is the texture, and some textural defects such as weak gel firmness and syneresis likely occur in various types of yogurts, affecting consumer acceptance. In this regard, various strategies such as enrichment of milk-based with different additives and ingredients such as protein-based components (skimmed milk powder (SMP), whey protein-based powders (WP), casein-based powders (CP), and suitable stabilizers, as well as modification of processing conditions (homogenization, fermentation, and cooling), can be applied in order to reduce syneresis. The most effective proteins and stabilizers in syneresis reduction are CP and gelatin, respectively. Furthermore, yogurt's water holding capacity and syneresis can be affected by the type of starter cultures, the protolithic activity, production of extracellular polysaccharides, and inoculation rate. Moreover, optimizing the heat treatment process (85 °C/30 min and 95 °C/5 min), homogenization (single or dual-stage), incubation temperature (around 40 °C), and two-step cooling process can decrease yogurt syneresis. This review is aimed to investigate the effect of fortification of the milk base with various additives and optimization of process conditions on improving texture and preventing syneresis in yogurt.

Administration of Bifidobacterium animalis subsp. lactis strain BB-12® in healthy children: characterization, functional composition, and metabolism of the gut microbiome

Introduction

The consumption of probiotics may influence children's gut microbiome and metabolome, which may reflect shifts in gut microbial diversity composition and metabolism. These potential changes might have a beneficial impact on health. However, there is a lack of evidence investigating the effect of probiotics on the gut microbiome and metabolome of children. We aimed to examine the potential impact of a two (Streptococcus thermophilus and Lactobacillus delbrueckii; S2) vs. three (S2 + Bifidobacterium animalis subsp. lactis strain BB-12) strain-supplemented yogurt.

Methods

Included in this study were 59 participants, aged one to five years old, recruited to phase I of a double-blinded, randomized controlled trial. Fecal samples were collected at baseline, after the intervention, and at twenty days post-intervention discontinuation, and untargeted metabolomics and shotgun metagenomics were performed.

Results

Shotgun metagenomics and metabolomic analyses showed no global changes in either intervention group's gut microbiome alpha or beta diversity indices, except for a lower microbial diversity in the S2 + BB12 group at Day 30. The relative abundance of the two and three intervention bacteria increased in the S2 and S2 + BB12 groups, respectively, from Day 0 to Day 10. In the S2 + BB12 group, the abundance of several fecal metabolites increased at Day 10, including alanine, glycine, lysine, phenylalanine, serine, and valine. These fecal metabolite changes did not occur in the S2 group.

Discussion

In conclusion, there were were no significant differences in the global metagenomic or metabolomic profiles between healthy children receiving two (S2) vs. three (S2 + BB12) probiotic strains for 10 days. Nevertheless, we observed a significant increase (Day 0 to Day 10) in the relative abundance of the two and three probiotics administered in the S2 and S2 + BB12 groups, respectively, indicating the intervention had a measurable impact on the bacteria of interest in the gut microbiome. Future research using longer probiotic intervention durations and in children at risk for gastrointestinal disorders may elucidate if functional metabolite changes confer a protective gastrointestinal effect.

Yoghurt Intake and Gastric Cancer: A Pooled Analysis of 16 Studies of the StoP Consortium

BACKGROUND

Yoghurt can modify gastrointestinal disease risk, possibly acting on gut microbiota. Our study aimed at exploring the under-investigated association between yoghurt and gastric cancer (GC).

METHODS

We pooled data from 16 studies from the Stomach Cancer Pooling (StoP) Project. Total yoghurt intake was derived from food frequency questionnaires. We calculated study-specific odds ratios (ORs) of GC and the corresponding 95% confidence intervals (CIs) for increasing categories of yoghurt consumption using univariate and multivariable unconditional logistic regression models. A two-stage analysis, with a meta-analysis of the pooled adjusted data, was conducted.

RESULTS

The analysis included 6278 GC cases and 14,181 controls, including 1179 cardia and 3463 non-cardia, 1191 diffuse and 1717 intestinal cases. The overall meta-analysis revealed no association between increasing portions of yoghurt intake (continuous) and GC (OR = 0.98, 95% CI = 0.94-1.02). When restricting to cohort studies, a borderline inverse relationship was found (OR = 0.93, 95% CI = 0.88-0.99). The adjusted and unadjusted OR were 0.92 (95% CI = 0.85-0.99) and 0.78 (95% CI = 0.73-0.84) for any vs. no yoghurt consumption and GC risk. The OR for 1 category of increase in yoghurt intake was 0.96 (95% CI = 0.91-1.02) for cardia, 1.03 (95% CI = 1.00-1.07) for non-cardia, 1.12 (95% CI = 1.07-1.19) for diffuse and 1.02 (95% CI = 0.97-1.06) for intestinal GC. No effect was seen within hospital-based and population-based studies, nor in men or women.

CONCLUSIONS

We found no association between yoghurt and GC in the main adjusted models, despite sensitivity analyses suggesting a protective effect. Additional studies should further address this association.

Development of functional yogurt by using freeze-drying on soybean and mung bean peel powders

Introduction

Plant-based yogurt has earned much interest in current times due to the rising demand for milk substitutes, which is tied to ethical and health needs.

Methods

Freeze-drying impact on soybean peel powder (SPP) and mung bean peel powder (MPP) and their use in creating functional yogurt at various concentrations was checked. In functional yogurt, total flavonoid content (TFC), total phenolic content (TPC), antioxidant activity and chemical profile are checked.

Results

The maximum concentration of TPC was 4.65±0.05 (mg GAE/g), TFC was 1.74±0.05 (CE mg/g) and 82.99 ± 0.02 % antioxidant activity was calculated in sample T6, having the highest concentration of SPP, which was substantially more significant than the treatment samples containing MPP. Sensory attributes of the yogurt samples were analyzed, which indicated a decrease when SPP and MPP values increased when introduced at 3 or 6 % of an optimum level. There was no notable loss of the sensory profile compared to the control group. The results were found to be significant at p < 0.05. The freeze-dried SPP had the complete chemical composition compared to MPP except for ash and fiber content.

Discussion

The physicochemical profile of the treatments of functional yogurt had a linear proportional connection in the percentage of both powders in the meantime. When both the dry level of powders increased, the protein and fat levels decreased. In the food industry, the freeze-dried soybean peel and the peel of mung bean can be utilized in functional yogurt as a source of bioactive components.

Plain set and stirred yogurt with different additives: implementation of food safety system as quality checkpoints

Hazard Analysis Critical Control Point (HACCP) is a risk management protocol developed to ensure food safety through a precautionary approach that is believed to offer assurances in producing safe food for customers. Yogurt is made in a number of phases, commencing with the collection of raw milk and ending with consumer consumption. While this is happening, major economic and health issues might arise from exposing the manufacturing line to biological, chemical, and/or physical contaminations. As a result, the decision tree approach was used to determine the CCPs during the production of yogurt. Additionally, biological dangers are incorporated as a by-product of the system's implementation performance. In particular, the plain set and nut puree-honey-fortified stirred yogurt manufacturing techniques are highlighted for the first time in this study. The potential manufacturing risks are described for the first time, together with information on how HACCP plans may guard against major risks that could result in the production of yogurt that is not in compliance with established standards.

Biological Role of Nutrients, Food and Dietary Patterns in the Prevention and Clinical Management of Major Depressive Disorder

Major Depressive Disorder (MDD) is a growing disabling condition affecting around 280 million people worldwide. This complex entity is the result of the interplay between biological, psychological, and sociocultural factors, and compelling evidence suggests that MDD can be considered a disease that occurs as a consequence of an evolutionary mismatch and unhealthy lifestyle habits. In this context, diet is one of the core pillars of health, influencing multiple biological processes in the brain and the entire body. It seems that there is a bidirectional relationship between MDD and malnutrition, and depressed individuals often lack certain critical nutrients along with an aberrant dietary pattern. Thus, dietary interventions are one of the most promising tools to explore in the field of MDD, as there are a specific group of nutrients (i.e., omega 3, vitamins, polyphenols, and caffeine), foods (fish, nuts, seeds fruits, vegetables, coffee/tea, and fermented products) or dietary supplements (such as S-adenosylmethionine, acetyl carnitine, creatine, amino acids, etc.), which are being currently studied. Likewise, the entire nutritional context and the dietary pattern seem to be another potential area of study, and some strategies such as the Mediterranean diet have demonstrated some relevant benefits in patients with MDD; although, further efforts are still needed. In the present work, we will explore the state-of-the-art diet in the prevention and clinical support of MDD, focusing on the biological properties of its main nutrients, foods, and dietary patterns and their possible implications for these patients.

Lactic acid production from food waste using a microbial consortium: Focus on key parameters for process upscaling and fermentation residues valorization

In this study, the production of lactic acid from food waste in industrially relevant conditions was investigated. Laboratory assays were first performed in batch conditions to determine the suitable operational parameters for an efficient lactic acid production. The use of compost as inoculum, the regulation of temperature at 35 °C and pH at 5 enhanced the development of Lactobacillus sp. resulting in the production of 70 g/L of lactic acid with a selectivity of 89% over the other carboxylic acids. Those parameters were then applied at pilot scale in successive fed-batch fermentations. The subsequent high concentration (68 g/L), yield (0.38 g/gTS) and selectivity (77%) in lactic acid demonstrated the applicability of the process. To integrate the process into a complete value chain, fermentation residues were then converted into biogas through anaerobic digestion. Lastly, the experiment was successfully replicated using commercial and municipal waste collected in France.

Functional Foods, Nutraceuticals and Probiotics: A Focus on Human Health

Functional foods are classified as traditional or staple foods that provide an essential nutritional level and share potentially positive effects on host health, including the reduction of disease by optimizing the immune system’s ability to prevent and control infections by pathogens, as well as pathologies that cause functional alterations in the host. This chapter reviews the most recent research and advances in this area and discusses some perspectives on what the future holds in this area.

Lactose: Characteristics, Food and Drug-Related Applications, and Its Possible Substitutions in Meeting the Needs of People with Lactose Intolerance

The recent growing interest in lactose intolerance has resulted in the proliferation of lactose-free products by food manufacturing companies. Since updated papers about lactose and its uses are missing, the main purpose of this review is to investigate this sugar comprehensively. Firstly, its chemical and physical characteristics were studied, following its employment in the food and drug industries. The positive and negative health-related effects of lactose are reported, focusing on the condition of lactose intolerance, for which an adequate lactose-free diet has to be followed to avoid symptoms that impairs quality of life. Considering that EU legislation on lactose-free product labelling is still controversial, suitable options for producing and identifying lactose-free products are suggested, in order to meet lactose-intolerant people’s needs.

Effect of Freeze-Drying on Apple Pomace and Pomegranate Peel Powders Used as a Source of Bioactive Ingredients for the Development of Functional Yogurt

Agro-industrial by-products of fruits have turned into an essential source of bioactive products. This study examined the effect of freeze-drying on apple pomace powder (APP) and pomegranate peel powder (PPP) and their utilization in functional yogurt development at different concentrations. Freeze-dried powders in functional yogurt were investigated by chemical profile and bioactive characterization of total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity. The highest concentration of TPC (4.64) mg GAE/g, TFC (1.73 ± 0.00) CE mg/g, and antioxidant activity (83.87 ± 0.02) % was investigated in the yogurt sample T6, having the maximum amount of PPP in it, which was significantly higher compared to the treatments having APP. Yogurt samples were analyzed for their sensory attributes, which showed a decline with the increase in both APP and PPP concentrations in contrast by introducing the optimum levels of APP and PPP (3% or 6%); hence, no significant loss in sensory profile was found as compared to the control samples. The results were found to be significant at the level ( $p<0.05$ ). In terms of the freeze-dried APP and PPP results, the APP samples had the most complete chemical composition, with the exception of fiber and ash concentration. Treatments of functional yogurt were prepared for their physicochemical profile, which demonstrated a straight proportionate relationship between the proportions of both powders in the meantime. Protein and fat levels were likely to decrease as both dry powder levels increased. Hence, apple pomace and pomegranate peel can be used after freeze-drying as a rich source of bioactive compounds in functional yogurt in the food industry.

Distribution, Diversity and Roles of CRISPR-Cas Systems in Human and Animal Pathogenic Streptococci

Streptococci form a wide group of bacteria and are involved in both human and animal pathologies. Among pathogenic isolates, differences have been highlighted especially concerning their adaptation and virulence profiles. CRISPR-Cas systems have been identified in bacteria and many streptococci harbor one or more systems, particularly subtypes I-C, II-A, and III-A. Since the demonstration that CRISPR-Cas act as an adaptive immune system in Streptococcus thermophilus, a lactic bacteria, the diversity and role of CRISPR-Cas were extended to many germs and functions were enlarged. Among those, the genome editing tool based on the properties of Cas endonucleases is used worldwide, and the recent attribution of the Nobel Prize illustrates the importance of this tool in the scientific world. Another application is CRISPR loci analysis, which allows to easily characterize isolates in order to understand the interactions of bacteria with their environment and visualize species evolution. In this review, we focused on the distribution, diversity and roles of CRISPR-Cas systems in the main pathogenic streptococci.

Yogurt consumption and colorectal cancer incidence and mortality in the Nurses' Health Study and the Health Professionals Follow-Up Study

BACKGROUND

Yogurt is a commonly consumed fermented food. Regular yogurt consumption may contribute to a favorable gut microbiome and gut health, but few epidemiologic studies have considered the relation between regular yogurt consumption and the incidence of and mortality from colorectal cancer.

OBJECTIVES

We used data from 2 large, prospective cohort studies, the Nurses' Health Study and the Health Professionals Follow-Up Study, to examine the role of yogurt consumption on colorectal cancer incidence and mortality.

METHODS

During 32 years of follow-up in 83,054 women (mean age at baseline, 45.7 years) and 26 years of follow-up in 43,269 men (mean age at baseline, 52.3 years), we documented a total of 2666 newly diagnosed cases of colorectal cancer in these cohorts. We modeled yogurt consumption at baseline and cumulatively updated it throughout follow-up. Results: Baseline yogurt consumption was associated with a reduced risk of colon cancer in age-adjusted analyses (P for trend < 0.001). Associations remained statistically significant after adjusting for potential confounders, including calcium and fiber intake (P for trend = 0.03), and were restricted to proximal colon cancer. The consumption of 1 + servings per week of yogurt at baseline, compared to no yogurt consumption, was associated with a multivariable HR of 0.84 (95% CI, 0.70-0.99; P trend = 0.04) for the proximal colon cancer incidence. Latency analyses suggested that the most important window of opportunity for regular yogurt consumption to prevent colorectal cancer was 16-20 years in the past. When yogurt consumption was cumulatively updated, associations attenuated and were no longer significant. No statistically significant inverse trend was observed between yogurt consumption and the colorectal cancer mortality.

CONCLUSIONS

In these large cohorts, the frequency of yogurt consumption was associated with a reduced risk of proximal colon cancer with a long latency period. No significant inverse trend was observed for colorectal cancer mortality.