Correlation between natural microbial load and formation of ropy slime affecting the superficial color of vacuum-packaged cooked sausage.

The present study outlines a comprehensive correlation between the natural microbial load, which is predominantly composed of heat-resistant sporous-forming Bacillus, and the changes in the original properties related to the superficial color of vacuum-packaged cooked sausages. For this purpose, microbial growth curves were plotted by stimulating the growth of the natural microbiota in sausage packages at different temperatures. The correlations were investigated during sample incubation by the instrumental evaluation of color and the ropy slime detection on the sausage surface. The entrance of the natural microbiota into the stationary phase (ca. 9.3 log cfu/g) resulted in changes in the superficial color, which was demonstrated by the discoloration of vacuum-packaged cooked sausages. Therefore, it seems to be a suitable borderline for predictive models applied in durability studies that aim to estimate the period in which vacuum-packaged cooked sausages keep their typical superficial color, anticipating product refusal in markets.

Atomistic-geometric simulations to investigate the mechanical stability of monocrystalline sI methane hydrates under pressure.

Gas hydrate mechanical stability under pressure is critically important in energy supply, global warming, and carbon-neutral technologies. The stability of these polyhedral guest-host crystals under increasing pressure is affected by host cage type and face connectivity as well as guest gas occupancy. The geometry-imposed cage connectivity generates crystal lattices that include inclusion-matrix material composite structures. In this paper, we integrate Density Functional Theory simulations with a polyhedral-inspired composite material model that quantifies stability limits, failure modes, and the impact of the type of cage occupancy. DFT reveals the existence of two failure mechanisms under increasing pressure: (i) a multistep lattice breakdown under total occupancy and under only large cage occupancy and (ii) a single-step breakdown under zero occupancy as well as with only small cage occupancy. The DFT-composite model predicts optimal occupancy pathways to generate strength and critical occupancy pathways to promote decomposition.

Interfacial Effects during Phase Change in Multiple Levitated Tetrahydrofuran Hydrate Droplets.

Recent strategies developed to examine the nucleation of crystal structures like tetrahydrofuran (THF) hydrates without the effects of a solid interface have included acoustic levitation, where only a liquid-gas interface initially exists. However, the ability now exists to levitate and freeze multiple droplets simultaneously, which could reveal interdroplet effects and provide further insight into interfacial nucleation phenomena. In this study, using direct digital and infrared imaging techniques, the freezing of up to three simultaneous THF hydrate droplets was investigated for the first time. Nucleation was initiated at the aqueous solution-air interface. Two pseudo-heterogeneous mechanisms created additional nucleation interfaces: one from cavitation effects entraining microbubbles and another from subvisible ice particles, also called hydrate-nucleating particles (HNPs), impacting the droplet surface. For systems containing droplets in both the second and third positions, nucleation was statistically simultaneous between all droplets. This effect may have been caused by the high liquid-solid interfacial pressures that developed at nucleation, causing some cracking in the initial hydrate shell around the droplet and releasing additional HNPs (now of hydrate) into the air. During crystallization, the THF hydrate droplets developed a completely white opacity, termed optical clarity loss (OCL). It was suggested that high hydrate growth rates within the droplet resulted in the capture of tiny air bubbles within the solid phase. In turn, light refraction through many smaller bubbles resulted in the OCL. These bubbles created structural inhomogeneities, which may explain how the volumetric expansion of the droplets upon complete solidification was 23.6% compared with 7.4% in pure, stationary THF hydrate systems. Finally, the thermal gradient that developed between the top and bottom of the droplet during melting resulted in a surface tension gradient along the air-liquid interface. In turn, convective cells developed within the droplet, causing it to spin rapidly about the horizontal axis.

Risk Factors Associated With Reoperative Surgery for Thyroid Malignancies: A Retrospective Cohort Study.

OBJECTIVE: To examine various factors associated with an increased risk of reoperation for persistent or recurrent malignant thyroid cancers. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary academic hospital centers. METHODS: Patients undergoing surgery for thyroid cancer at 2 tertiary academic institutions from 2006 to 2020 were included. Those who underwent a reoperative procedure were compared with patients only requiring 1 procedure. The Pearson chi-square and independent t test were used to compare group data accordingly. Furthermore, a binomial logistic regression was performed, while machine learning models were used to construct a predictive algorithm. RESULTS: This study included 2266 patients with surgically managed thyroid malignancy, of which 54 (2.4%) necessitated reoperations. Those requiring a second surgical procedure were more likely to be male (40.7% vs 20.9%, P < .001), undergo bilateral (24.1% vs 3.3%, P < .001) and lateral (16.7% vs 1.8%, P < .001) neck dissections, and have a greater number of metastatic lymph nodes (mean, 9.1 vs 3.5; P < .001) and a larger tumor size (mean, 3.0 vs 2.0 cm; P < .001). According to the binomial logistic regression model, lateral neck dissection, greater number of metastatic lymph nodes, and larger tumor size significantly increased the odds of necessitating a second procedure by 7.8 (95% CI, 2.523-24.083), 1.1 (95% CI, 1.032-1.152), and 1.3 (95% CI, 1.064-1.559), respectively. Last, machine learning models could not significantly predict the occurrence of reoperation. CONCLUSION: This study identified patient- and cancer-related characteristics associated with an increased risk of requiring reoperation for thyroid malignancies.

All-Atom Molecular Dynamics of Pure Water-Methane Gas Hydrate Systems under Pre-Nucleation Conditions: A Direct Comparison between Experiments and Simulations of Transport Properties for the Tip4p/Ice Water Model.

(1) Background: New technologies involving gas hydrates under pre-nucleation conditions such as gas separations and storage have become more prominent. This has necessitated the characterization and modeling of the transport properties of such systems. (2) Methodology: This work explored methane hydrate systems under pre-nucleation conditions. All-atom molecular dynamics simulations were used to quantify the performance of the TIP4P/2005 and TIP4P/Ice water models to predict the viscosity, diffusivity, and thermal conductivity using various formulations. (3) Results: Molecular simulation equilibrium was robustly demonstrated using various measures. The Green-Kubo estimation of viscosity outperformed other formulations when combined with TIP4P/Ice, and the same combination outperformed all TIP4P/2005 formulations. The Green-Kubo TIP4P/Ice estimation of viscosity overestimates (by 84% on average) the viscosity of methane hydrate systems under pre-nucleation conditions across all pressures considered (0-5 MPag). The presence of methane was found to increase the average number of hydrogen bonds over time (6.7-7.8%). TIP4P/Ice methane systems were also found to have 16-19% longer hydrogen bond lifetimes over pure water systems. (4) Conclusion: An inherent limitation in the current water force field for its application in the context of transport properties estimations for methane gas hydrate systems. A re-parametrization of the current force field is suggested as a starting point. Until then, this work may serve as a characterization of the deviance in viscosity prediction.

Dynamic viscosity of methane hydrate systems from non-Einsteinian, plasma-functionalized carbon nanotube nanofluids.

The viscosity of oxygen-functionalized multi-walled carbon nanotube (O-MWCNT) nanofluids was measured for concentrations from 0.1 to 10 ppm under conditions of 0 to 30 MPag pressures and 0 to 10 °C temperatures. The presence of O-MWCNTs did not affect the temperature dependence of viscosity but did reduce the effective viscosity of solution due to cumulative hydrogen bond-disrupting surface effects, which overcame internal drag forces. O-MWCNTs added a weak pressure dependence to the viscosity of solution because of their ability to align more with the flow direction as pressure increased. In the liquid to hydrate phase transition, the times to reach the maximum viscosity were faster in O-MWCNT systems compared to the pure water baseline. However, the presence of O-MWCNTs limited the conditions at which hydrates formed as increased nanoparticle collisions in those systems inhibited the formation of critical clusters of hydrate nuclei. The times to viscosity values most relevant to technological applications were minimally 28.02% (200 mPa s) and 21.08% (500 mPa s) slower than the baseline, both in the 1 ppm system, even though all systems were faster to the final viscosity. This was attributed to O-MWCNT entanglement, which resulted in a hydrate slurry occurring at lower viscosity values.

TinyLev acoustically levitated water: Direct observation of collective, inter-droplet effects through morphological and thermal analysis of multiple droplets.

HYPOTHESIS: Understanding the crystallization of atmospheric water can require levitation techniques to avoid the influence of container walls. Recently, an acoustic levitation device called the TinyLev was designed, which can levitate multiple droplets at room temperature. Proximal crystallization may affect droplet phase change and morphological characteristics. METHODOLOGY: In this study, acoustically levitated pure water droplets were frozen individually and in pairs or triplets using a TinyLev device. Nucleation, bulk crystal growth, and melting were observed using digital and infrared cameras concurrently. FINDINGS: Initially, the acoustic field forced the droplets into an oblate spheroid shape, though the counteracting force of the cooling stream caused them to circularize. Droplet geometry was thus the net result of streaming forces and surface tension at the acoustic boundary layer/air-liquid interface. Nucleation was determined to be neither homogeneous nor heterogeneous but secondary, and thus dependent on the cooling rate and not on the degree of supercooling. It was likely initiated by aerosolized ice particles from the air or from droplets that had already nucleated and broken up. The latter secondary ice production process resulted in multi-drop systems with statistically identical nucleation times. Notably, this meant that the presence of interfacial rupture at an adjacent droplet could influence the crystallization behaviour of another. After the formation of an initial ice shell around the individual droplets, dendritic protrusions grew from the droplet surface, likely seeded by the same ice particles that caused nucleation, but at a quasi-liquid layer. When freezing was complete, it was determined that the frozen core had undergone a volumetric expansion of 30.75%, compared to 9% for pure, sessile water expansion. This significantly greater expansion may have resulted from entrained air bubbles at the inner solid-liquid interface and oscillations at the moving phase boundary caused by changes in local acoustic forces. Soon after melting began, acoustic streaming, the buoyancy of the remaining ice, and convective currents caused by both an inner thermal gradient and thermocapillary effects along the air-liquid interface, all contributed to the droplet spinning about the horizontal axis.

Energy Minimisers with Prescribed Jacobian.

We consider the class of planar maps with Jacobian prescribed to be a fixed radially symmetric function f and which, moreover, fixes the boundary of a ball; we then study maps which minimise the 2p-Dirichlet energy in this class. We find a quantity λ [ f ] which controls the symmetry, uniqueness and regularity of minimisers: if λ [ f ] ≤ 1 then minimisers are symmetric and unique; if λ [ f ] is large but finite then there may be uncountably many minimisers, none of which is symmetric, although all of them have optimal regularity; if λ [ f ] is infinite then generically minimisers have lower regularity. In particular, this result gives a negative answer to a question of Hélein (Ann. Inst. H. Poincaré Anal. Non Linéaire 11(3):275-296, 1994). Some of our results also extend to the setting where the ball is replaced by R 2 and boundary conditions are not prescribed.

Pathophysiology and Biomarker Potential of Fatty Acid Ethyl Ester Elevation During Alcoholic Pancreatitis.

BACKGROUND & AIMS: The role of fatty acid ethyl esters (FAEEs) during human alcoholic pancreatitis is unknown. We compared FAEEs levels with their nonesterified fatty acids (NEFAs) precursors during alcohol intoxication and clinical alcoholic pancreatitis. The pathophysiology underlying FAEEs increase and their role as diagnostic biomarkers for alcoholic pancreatitis was investigated. METHODS: A prospective blinded study compared FAEEs, NEFAs, and ethanol blood levels on hospitalization for alcoholic pancreatitis (n = 31), alcohol intoxication (n = 25), and in normal controls (n = 43). Serum FAEEs were measured at admission for nonalcoholic pancreatitis (n = 75). Mechanistic cell and animal studies were done. RESULTS: Median FAEEs were similarly elevated during alcohol intoxication (205 nmol/L; 95% confidence interval [CI], 71.8-515 nmol/L, P < .001) and alcoholic pancreatitis (103.1 nmol/L; 95% CI, 53-689 nmol/L, P < .001) vs controls (1.7 nmol/L; 95% CI, 0.02-4.3 nmol/L) or nonalcoholic pancreatitis (8 nmol/L; 95% CI, 1.1-11.5 nmol/L). Alcoholic pancreatitis increased serum NEFAs (1024 ± 710 µmol/L vs 307 ± 185 µmol/L in controls, P < .05). FAEEs comprised 0.1% to 2% of the parent NEFA concentrations. FAEES correlated strongly with NEFAs independent of ethanol levels in alcoholic pancreatitis but not during alcohol intoxication. On receiver operating characteristic curve analysis for diagnosing alcoholic pancreatitis, the area under the curve for serum FAEEs was 0.87 (95% CI, 0.78-0.95, P < .001). In mice and cells, alcohol administration transiently increased all FAEEs. Oleic acid ethyl ester was the only FAEE with a sustained increase up to 24 hours after intraperitoneal oleic acid plus ethanol administration. CONCLUSIONS: The sustained, alcohol-independent, large (20- to 50-fold) increase in circulating FAEEs during alcoholic pancreatitis results from their visceral release and mirrors the 2- to 4-fold increase in parent NEFA. The large areas under the curve of FAEEs on receiver operating characteristic curve analysis supports their role as alcoholic pancreatitis biomarkers.

Renal function in children with a congenital solitary functioning kidney: A systematic review.

INTRODUCTION: Abnormal renal development that results in lack of function or development of one of two kidneys is known as congenital solitary functioning kidney (CSFK). Two well characterized sub-categories of CFSK are unilateral renal agenesis (URA) and multicystic dysplastic kidney (MCDK). This systematic review sought to evaluate the change in renal function in children ≤18 years old with a CSFK as a result of URA or MCDK. METHODS: A literature search in MEDLINE and Embase was conducted (1946 to July 13, 2020). All relevant articles were retrieved and evaluated based on pre-selected criteria by two independent researchers. Data was then extracted from variables of interest and conflicts were resolved by a third researcher. The primary outcome was renal function, and the secondary outcomes were proteinuria and hypertension. RESULTS: Forty-five studies were included, of which 49% (n = 22) were retrospective and/or 58% (n = 26) were cohort studies. A combined total of 2148 and 885 patients were diagnosed with MCDK or URA, respectively. The proportion of children with worsened renal function at follow-up was found to be 8.4% (95% CI: 5.2%-13.4%). Among the studies reporting renal function as a group mean or median at follow-up, 84% (21/25) had a GFR/CrCl above 90 (mL/min/1.73  m2/ml/min). In terms of secondary outcomes, the proportion of children with proteinuria and hypertension was found to be 10.1% (95% CI: 6.9%-14.6%) and 7.4% (95% CI: 5.0%-10.9%), respectively. CONCLUSION: The risk of developing proteinuria (10.1%), hypertension (7.4%), and/or worsened renal function (8.4%) for children with CFSK as a result of MCDK or URA is low. However, the level of evidence in the literature is weak. Further research is needed to identify the predisposing factors that may differentiate the small subset of children with CSFK at a higher risk of developing adverse renal outcomes.

The Dirichlet problem for the Jacobian equation in critical and supercritical Sobolev spaces.

We study existence and regularity of solutions to the Dirichlet problem for the prescribed Jacobian equation, det D u = f , where f is integrable and bounded away from zero. In particular, we take f ∈ L p , where p > 1 , or in L log L . We prove that for a Baire-generic f in either space there are no solutions with the expected regularity.

Role of milk and honey in the tolerance of lactobacilli to oxidative stress.

In the development of functional probiotic food, the carrier matrices should be carefully selected and optimized to ensure the highest levels of probiotic survival in the symbiotic food along storage. Because milk and honey food matrices are rich in antioxidant substances, the aim of the research was to evaluate their effect in protecting lactobacilli from reactive oxygen species (ROS) generated by the addition of hydrogen peroxide. Viability assays were performed with and without the addition of H2O2, in three different matrices: 0.9% peptone saline, 5% honey, or 12% reconstituted skim milk. The milk matrix provided protection for the Lacticaseibacillus paracasei DTA83 and Lacticaseibacillus rhamnosus DTA76. However, this protective effect was not observed in the survival of Lactobacillus acidophilus La 5. Honey solution did not maintain the viability of probiotic microorganisms exposed to hydrogen peroxide and, on the contrary, caused a significant reduction in the population of L. rhamnosus DTA76 (p < 0.001). Lower membrane lipid peroxidation due to H2O2 exposure was observed in L. acidophilus La 5 and L. rhamnosus DTA76, but this marker showed no relation with viability. It was concluded: (i) lactobacilli from the Lacticaseibacillus genus were the ones that benefited most from the lactic environment; (ii) the absence of the protective effect of honey was possibly due to the presence of Fe2+ which reacts with H2O2 to produce hydroxyl radicals; and (iii) cell viability did not correlate with membrane lipid peroxidation, and it is not a good marker to evaluate this type of damage in cells of different microorganisms.

From the vineyard to the cellar: new insights of Starmerella bacillaris (synonym Candida zemplinina) technological properties and genomic perspective.

A large diversity of yeasts can be involved in alcoholic fermentation; however, Starmerella bacillaris strains have gained great attention due to their relevant and particular characteristics. S. bacillaris is commonly known as an osmotolerant, acidogenic, psychrotolerant, and fructophilic yeast. Most strains of this species are high producers of glycerol and show low ethanol production rates, being highlighted as promising alternatives to the manufacture of low-alcohol beverages. The increased production of high alcohols, such as benzyl alcohol that has antifungal and antibacterial properties, highlights S. bacillaris potential as a biocontrol agent. After harvest, antifungal yeasts become part of the must microbiota and may also improve the fermentation process. Moreover, during the fermentation, S. bacillaris releases important molecules with biotechnological properties, such as mannoproteins and glutathione. Considering the potential biotechnological properties of S. bacillaris strains, this review presents an overview of recent trends concerning the application of S. bacillaris in fermented beverages. KEY POINTS: •S. bacillaris as an alternative to the production of low-alcohol beverages. •S. bacillaris strains present biocontrol potential. •Molecules released by S. bacillaris may be of great biotechnological interest.

Craft Beers Fermented by Potential Probiotic Yeast or Lacticaseibacilli Strains Promote Antidepressant-Like Behavior in Swiss Webster Mice.

This study aimed to produce a probiotic-containing functional wheat beer (PWB) by an axenic culture system with potential probiotic Saccharomyces cerevisiae var boulardii 17 and probiotic-containing functional sour beer (PSB) by a semi-separated co-cultivation system with potential probiotic Lacticaseibacillus paracasei DTA 81 and Saccharomyces cerevisiae S-04. Additionally, results obtained from in vivo behavioral tests with Swiss Webster mice treated with PWB or PSB were provided, which is scarce in the current literature. Although the use of S. boulardii to produce beers is not a novelty, this study demonstrated that S. boulardii 17 performance on sugar wort stills not completely elucidated; therefore, further studies should be considered before using the strain in industrial-scale production. Co-culture systems with lacticaseibacilli strain and S. cerevisiae have been reported in the literature for PSB production. However, lacticaseibacilli survivability in beer can be improved by semi-separated co-cultivation systems, highlighting the importance of growing lacticaseibacilli in the wort before yeast pitching. Besides, kettle hopping must be chosen as the method for hop addition to produce PSB. The dry-hopping method may prevent iso-alpha formation in the wort; however, a tendency to sediment can drag cells at the tank bottom and negatively affect L. paracasei DTA 81 viability. Despite stress factors from the matrices and the stressful conditions encountered during GI transit, potential probiotic S. boulardii 17 and potential probiotic L. paracasei DTA 81 withstood at sufficient doses to promote antidepressant effects in the mice group treated with PWB or PSB, respectively.

Adipose saturation reduces lipotoxic systemic inflammation and explains the obesity paradox.

Obesity sometimes seems protective in disease. This obesity paradox is predominantly described in reports from the Western Hemisphere during acute illnesses. Since adipose triglyceride composition corresponds to long-term dietary patterns, we performed a meta-analysis modeling the effect of obesity on severity of acute pancreatitis, in the context of dietary patterns of the countries from which the studies originated. Increased severity was noted in leaner populations with a higher proportion of unsaturated fat intake. In mice, greater hydrolysis of unsaturated visceral triglyceride caused worse organ failure during pancreatitis, even when the mice were leaner than those having saturated triglyceride. Saturation interfered with triglyceride's interaction and lipolysis by pancreatic triglyceride lipase, which mediates organ failure. Unsaturation increased fatty acid monomers in vivo and aqueous media, resulting in greater lipotoxic cellular responses and organ failure. Therefore, visceral triglyceride saturation reduces the ensuing lipotoxicity despite higher adiposity, thus explaining the obesity paradox.

Potentially probiotic or postbiotic pre-converted nitrite from celery produced by an axenic culture system with probiotic lacticaseibacilli strain.

The present study evaluated the use of the probiotic Lacticaseibacillus paracasei DTA-83 as a nitrite-reducing agent to produce potentially probiotic or postbiotic pre-converted nitrite from celery. The results obtained were compared to those achieved by direct addition of sodium nitrite for the typical reddish color formation in cooked pork sausages and the inhibitory potential against the growth of target microorganisms, including the clostridia group. Regarding the sausages color, similar findings were observed when comparing the use of pre-converted nitrite from celery produced by L. paracasei DTA-83 and the direct addition of sodium nitrite. Additionally, it presented an inhibitory effect against Salmonella spp., which was not observed with the direct addition of nitrite, revealing a potential strategy to control salmonellosis in the matrix. However, a non-equivalent preservative effect against Clostridium perfringens (INCQS 215) was determined. The results highlight a promising alternative to produce probiotic or postbiotic meat ingredients; however, further studies should be conducted to investigate doses that achieve microbial control.

Complete Genome Sequence and Carbohydrates-Active EnZymes (CAZymes) Analysis of Lactobacillus paracasei DTA72, a Potential Probiotic Strain with Strong Capability to Use Inulin.

The whole genome sequence of Lactobacillus paracasei DTA72, isolated from healthy infant feces, is reported, along with the Carbohydrates-Active enZymes (CAZymes) analysis and an in silico safety assessment. Strain DTA72 had previously demonstrated some interesting potential probiotic features, such as a good resistance to gastrointestinal conditions and an anti-Listeria activity. The 3.1 Mb sequenced genome consists of 3116 protein-coding sequences distributed on 340 SEED subsystems. In the present study, we analyzed the fermentation capability of strain DTA72 on six different carbohydrate sources, namely, glucose, fructose, lactose, galactose, xylose, and inulin by using phenotypical and genomic approaches. Interestingly, L. paracasei DTA72 evidenced the best growth performances on inulin with a much shorter lag phase and higher number of cells at the stationary phase in comparison with all the sugars tested. The CAZyme analysis using the predicted amino acid sequences detected 80 enzymes, distributed into the five CAZymes classes. Moreover, the in silico analysis revealed the absence of blood hemolytic genes, transmissible antibiotic resistances, and plasmids in DTA72. The results described in this study, together with those previously reported and particularly the strong capability to utilize inulin as energy source, make DTA72 a very interesting potential probiotic strain to be considered for the production of synbiotic foods. The complete genome data have been deposited in GenBank under the accession number WUJH00000000.

Pancreatic triglyceride lipase mediates lipotoxic systemic inflammation.

Visceral adipose tissue plays a critical role in numerous diseases. Although imaging studies often show adipose involvement in abdominal diseases, their outcomes may vary from being a mild self-limited illness to one with systemic inflammation and organ failure. We therefore compared the pattern of visceral adipose injury during acute pancreatitis and acute diverticulitis to determine its role in organ failure. Acute pancreatitis-associated adipose tissue had ongoing lipolysis in the absence of adipocyte triglyceride lipase (ATGL). Pancreatic lipase injected into mouse visceral adipose tissue hydrolyzed adipose triglyceride and generated excess nonesterified fatty acids (NEFAs), which caused organ failure in the absence of acute pancreatitis. Pancreatic triglyceride lipase (PNLIP) increased in adipose tissue during pancreatitis and entered adipocytes by multiple mechanisms, hydrolyzing adipose triglyceride and generating excess NEFAs. During pancreatitis, obese PNLIP-knockout mice, unlike obese adipocyte-specific ATGL knockouts, had lower visceral adipose tissue lipolysis, milder inflammation, less severe organ failure, and improved survival. PNLIP-knockout mice, unlike ATGL knockouts, were protected from adipocyte-induced pancreatic acinar injury without affecting NEFA signaling or acute pancreatitis induction. Therefore, during pancreatitis, unlike diverticulitis, PNLIP leaking into visceral adipose tissue can cause excessive visceral adipose tissue lipolysis independently of adipocyte-autonomous ATGL, and thereby worsen organ failure.

Safety and Stability of Two Potentially Probiotic Lactobacillus Strains After In Vitro Gastrointestinal Transit.

According to FAO and WHO, probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Most probiotic bacteria used today belong to the genera Lactobacillus and Bifidobacterium and are of animal or human origin. The fundamental characteristic routinely evaluated in potential probiotics strains is their limited viability loss during gastrointestinal transit (GIT), but to date, no studies reported whether probiotics, besides viability, still also maintain their beneficial properties intact. To study this aspect, we considered two strains, Lactobacillus rhamnosus DTA 79 and L. paracasei DTA 83, previously characterised for the presence of some probiotic properties, isolated from faeces of 7- to 21-day-old babies. Here, we examined some additional properties, namely antibiotic resistance, resistance to lysozyme, presence of haemolytic activity and inhibition of pathogen biofilm formation. We then tested the effect of in vitro GIT on all these features and our results show evidence that this procedure had in some cases limited and in others no significant effects on them. Additionally, we examined the gastrointestinal resistance of the strains after skim milk fermentation and successive storage of the product for 20 and 40 days at refrigeration temperature, to see whether prolonged storage could weaken cell resistance to GIT. Our results demonstrate that a protracted refrigeration period before in vitro GIT did not affect or influenced very weakly this essential probiotic property.

Growth Parameters and Survivability of Saccharomyces boulardii for Probiotic Alcoholic Beverages Development.

The aim of this research was to optimize the growth parameters (pH, ethanol tolerance, initial cell concentration and temperature) for Saccharomyces boulardii and its tolerance to in vitro gastrointestinal conditions for probiotic alcoholic beverage development. Placket-Burman screening was used to select only statistically significant variables, and the polynomial mathematical model for yeast growth was obtained by central composite rotatable design. Confirmation experiments to determine the kinetic parameters for yeast growth were carried out by controlling the temperature and pH. Soon after, the survivability of yeast was tested under in vitro conditions mimicking the human upper gastrointestinal transit. S. boulardii had suitable resistance to alcohol and gastrointestinal conditions for probiotic alcoholic beverage development.