The Impact of Gluten Friendly Flour on the Functionality of an Active Drink: Viability of Lactobacillus acidophilus in a Fermented Milk.

The Gluten FriendlyTM Technology is an innovative method that induces structural changes in gluten proteins. In this paper a synbiotic fermented milk, containing Lactobacillus acidophilus La-5 and Gluten Friendly Flour (GFF), was proposed. A mixture design was used to combine flour, temperature and probiotic to study the effects of these variables on the acidification. The experiments were done on both GFF and control flour (CF). Thus, the following conditions were chosen to produce the fermented milk: L. acidophilus at 6.5 log cfu/ml; flour at 2.5 g/l; temperature at 37°C. Then, the fermented milk was produced and stored at 4°C for 90 days. The most important result was the positive effect of GFF on the viability of the probiotic, with a prolongation of the shoulder length to 20 days (12-13 days in the control). Moreover, GFF did not act on the sensory scores and on the physico-chemical parameters.

Lactobacillus plantarum 5BG Survives During Refrigerated Storage Bio-Preserving Packaged Spanish-Style Table Olives (cv. Bella di Cerignola).

This paper proposes bio-preservation as a tool to assure quality and safety of Spanish-style table olives cv. Bella di Cerignola. Lactobacillus plantarum 5BG was inoculated in ready to sell olives packaged in an industrial plant by using a half-volume brine (4% NaCl; 2% sucrose). The samples were stored at 4°C. The survival of the inoculated strain, the microbiological quality, the sensory scores and the survival of a strain of Listeria monocytogenes inoculated in brines were evaluated. The persistence of the Lb. plantarum bio-preserving culture was confirmed on olives (≥6.5 Log CFU/g) and in brine (≥7 Log CFU/ml). Bio-preserved olives (SET1) showed a better sensory profile than chemically acidified control olives (SET2) and the texture was the real discriminative parameter among samples. Bio-preserved olives recorded better scores during storage because of their ability to retain good hardness, crunchiness, and fibrousness without cracks. The inoculation of Lb. plantarum positively acted on the safety of olives, as the D-value of L. monocytogenes was reduced from 40 (SET2) to 5 days (SET1). In conclusion, Lb. plantarum 5BG and the physico-chemical conditions achieved in the settled procedure are suitable for the industrial packaging of Bella di Cerignola table olives, improving the process by halving brining volumes and avoiding chemical stabilizers, and significantly reducing the salt concentration. The final product is also safely preserved for almost 5 months as suggested by the reduction of the survival rate of L. monocytogenes.

Survival of Listeria monocytogenes and Staphylococcus aureus in Synthetic Brines. Studying the Effects of Salt, Temperature and Sugar through the Approach of the Design of Experiments.

The fermentation of table olives relies on a complex microbiota of lactic acid bacteria (LAB), yeasts, and enterobacteria. Producers often add sugar to increase the growth rate of LAB, "but this practice could also increase the survival rate of some pathogens. Therefore, the main topic of this paper was to study the effect of sugar, salt and temperature on the survival of Staphylococcus aureus and Listeria monocytogenes in a synthetic brine through the theory of the Design of Experiments (simplex centroid). The addition of sugar could prolong the survival time of L. monocytogenes by 40 days, whereas an increase of the temperature caused a decrease of survival from 18 to 3 days. The survival time of S. aureus was prolonged by 50 days by combining sugar (2-4 g/l) and low temperatures (5-15°C). The use of desirability approach and prediction profiles suggests that the prolongation of the survival time of L. monocytogenes could be related to a shift in the geometrical shape of the death kinetic. This paper offers a structured statistical approach on the variables acting on the survival of two pathogens in brines and represents the first step to set up and design a predictive approach for olive producers.

An In Vitro Fermentation Study on the Effects of Gluten FriendlyTM Bread on Microbiota and Short Chain Fatty Acids of Fecal Samples from Healthy and Celiac Subjects.

Recently, an innovative gluten detoxification method called Gluten FriendlyTM (GF) has been developed. It induces structural modifications, which abolish the antigenic capacity of gluten and reduce the in vitro immunogenicity of the most common epitopes involved in celiac disease, without compromising the nutritional and technological properties. This study investigated the in vitro effects of GF bread (GFB) on the fecal microbiota from healthy and celiac individuals by a three-stage continuous fermentative system, which simulates the colon (vessel 1, proximal colon; vessel 2, transverse colon; and vessel 3, distal colon), as well as on the production of short chain fatty acids (SCFA, acetate, propionate, butyrate). The system was fed with GFB and the changes in microbiota through fluorescence in situ hybridization and in SCFA content were assessed. GFB exerted beneficial modulations such as bifidogenic effects in each compartment of the model both with healthy- and celiac-derived samples, as well as growth in Clostridium clusters XIVa+b in celiac-derived samples. Furthermore, increased levels of acetic acid were found in vessel 1 inoculated with the fecal microbiota of healthy individuals, as well as acetic and propionic in vessel 1 and 2 with celiac-derived samples. In addition, the use of multivariate approaches showed that the supplementation of GFB could result in a different modulation of the fecal microbiota and SCFA, as a function of initial equilibrium.

Microbial Resources and Enological Significance: Opportunities and Benefits.

Among the innovative trends in the wine sector, the continuous exploration of enological properties associated with wine microbial resources represents a cornerstone driver of quality improvement. Since the advent of starter cultures technology, the attention has been focused on intraspecific biodiversity within the primary species responsible for alcoholic fermentation (Saccharomyces cerevisiae) and, subsequently, for the so-called 'malolactic fermentation' (Oenococcus oeni). However, in the last decade, a relevant number of studies proposed the enological exploitation of an increasing number of species (e.g., non-Saccharomyces yeasts) associated with spontaneous fermentation in wine. These new species/strains may provide technological solutions to specific problems and/or improve sensory characteristics, such as complexity, mouth-feel and flavors. This review offers an overview of the available information on the enological/protechnological significance of microbial resources associated with winemaking, summarizing the opportunities and the benefits associated with the enological exploitation of this microbial potential. We discuss proposed solutions to improve quality and safety of wines (e.g., alternative starter cultures, multistrains starter cultures) and future perspectives.

Evaluation of Fungal Growth on Olive-Mill Wastewaters Treated at High Temperature and by High-Pressure Homogenization.

Reuse of olive mill wastewaters (OMWWs) in agriculture represents a significant challenge for health and safety of our planet. Phytotoxic compounds in OMWW generally prohibit use of untreated OMWWs for agricultural irrigation or direct discharge into surface waters. However, pretreated OMWW can have positive effects on chemical and microbiological soil characteristics, to fight against fungal soil-borne pathogens. Low amounts of OMWW following thermal (TT-OMWW) and high-pressure homogenization (HPH-OMWW) pretreatments counteracted growth of some of 12 soil-borne and/or pathogenic fungi examined. With fungal growth measured as standardized change in time to half maximum colony diameter, Δτ, overall, HPH-OMWW showed increased bioactivity, as increased mean Δτ from 3.0 to 4.8 days. Principal component analysis highlighted two fungal groups: Colletotrichum gloeosporioides, Alternaria alternata, Sclerotium rolfsii, and Rosellinia necatrix, with growth strongly inhibited by the treated OMWWs; and Aspergillus ochraceus and Phaeoacremonium parasiticum, with stimulated growth by the treated OMWWs. As a non-thermal treatment, HPH-OMWW generally shows improved positive effects, which potentially arise from preservation of the phenols.

Metabolites of Microbial Origin with an Impact on Health: Ochratoxin A and Biogenic Amines.

Safety and quality are significant challenges for food; namely, safety represents a big threat all over the world and is one of the most important goal to be achieved in both Western Society and Developing Countries. Wine safety mainly relies upon some metabolites and many of them are of microbial origin. The main goal of this review is a focus on two kinds of compounds (biogenic amines and mycotoxins, mainly Ochratoxin A) for their deleterious effects on health. For each class of compounds, we will focus on two different traits: (a) synthesis of the compounds in wine, with a brief description of the most important microorganisms and factors leading this phenomenon; (b) prevention and/or correction strategies and new trends. In addition, there is a focus on a recent predictive tool able to predict toxin contamination of grape, in order to perform some prevention approaches and achieve safe wine.

Bioactivity of essential oils: a review on their interaction with food components.

Essential oils (EOs) are liquid preparations, produced from plant materials. Although EOs showed a promising bioactivity in vitro, they could interact in foods with some components (fats, proteins, carbohydrates) and pH, thus many authors have reported that a significant effect of EOs toward spoiling and pathogenic microorganisms could be achieved in vivo by using higher amounts of oils. Different methods can be used to assess the bioactivity of EOs (disk diffusion and agar or broth dilution methods); however, there is not a standardized test and researchers propose and use different protocols (evaluating the Minimal Inhibitory Concentration, studying the survival curves, analysis through the scanning electron microscopy, etc.). Thereafter, the scope of this review is a focus on interactions of EOs with proteins, carbohydrates, oils, NaCl, and pH, as well as a brief description on the different protocols to assess their bioactivity both under in vivo and in vitro conditions.

Characterization of a wild strain of Alicyclobacillus acidoterrestris: heat resistance and implications for tomato juice.

UNLABELLED: This article reports the characterization of a wild strain of Alicyclobacillus acidoterrestris and describes the implications of the heat resistance of this microorganism in tomato juice. The strain (labeled as A. acidoterrestrisγ4) showed pH and temperature ranges for growth typical of the species (3.0 to 6.0 for the pH and 35 to 60 °C for the temperature); heat resistance in tomato juice was as follows: D(T) values of 40.65, 9.47, and 1.5 min (at 85, 90, and 95 °C, respectively) and z-value of 7 °C. A treatment at 70 °C for 15 min was found to be optimal for spore activation, whereas Malt Extract Agar, acidified to pH 4.5, showed good results for spore recovery. Concerning the implications of heat resistance of A. acidoterrestris on tomato juice, high temperatures required for spore inactivation determined a general decrease of the antioxidant activity (increase of the redox potential and reduction of the chain-breaking activity), but not the formation of brown compounds (namely, hydroxymethylfurfural), thus suggesting an effect on the secondary antioxidants (carotenoids and ascorbic acid) rather than on lycopene. PRACTICAL APPLICATION: Alicyclobacillus acidoterrestris is an emerging spore-forming microorganism, capable of causing spoilage in tomato juice. Due to their high thermal resistance, spores could be used as targets for the optimization of heat processing; this article reports on the assessment of thermal resistance of a wild strain of A. acidoterrestris, then focusing on the effect of the thermal treatment necessary to inactivate spores on the quality of tomato juice.

Evaluating in vitro antimicrobial activity of thymol toward hygiene-indicating and pathogenic bacteria.

Results of a study of the kinetics of bacterial inhibition by thymol in order to develop appropriate applications for the compound in food systems are presented. A modeling-based approach was used to provide a quantitative description of the antimicrobial activity of thymol toward some foodborne pathogens and hygiene-indicating bacteria, which could be postprocessing contaminants of ready-to-eat meat products. The effect of the active compound on the bacterial growth was assessed from growth kinetics curves and dose-response profiles in a wide range of thymol concentrations, i.e., from 50 to 1,000 ppm. Inhibitory data were produced using a macrodilution methodology based on a turbidimetric technique. Microbial response was discussed in terms of Gompertz's parameters as well as in terms of the active concentration of thymol affecting the growth status of microbial suspension (noninhibitory concentration and MIC). Results suggested that thymol can be successfully used as an alternative antimicrobial to increase the lag time as well as to decrease the maximum value of the growth index as reached in the stationary phase of the growth cycle for all investigated bacteria. Due to their high sensitivity to the antimicrobial stress as observed at sub-MIC, it is arguably a potential use of thymol for assurance of food safety and hygiene in combination with other preservative technologies. A quantitative evaluation of the antimicrobial properties of the active compound was performed using a macrodilution methodology based on a turbidimetric technique to produce inhibitory data. Both the growth kinetics and inhibition profile in a wide range of thymol concentrations were obtained for each test bacterium, mathematically modeled, and analyzed. Noninhibitory concentration and MIC were determined to investigate both the microbial sensibility and resistance toward thymol, and Gompertz's parameters were evaluated to assess the microbial response at each phase of growth cycle. The in vitro-obtained results suggested that thymol may be successfully used as a alternative preservative to increase the lag time as well as to decrease the maximum cell load reached in the stationary phase of growth cycle for all investigated bacteria.