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1.
J Dairy Res ; 87(2): 255-258, 2020 May.
Article in English | MEDLINE | ID: mdl-32398181

ABSTRACT

This research communication addresses the impact of the addition of Lactobacillus casei and/or carbonation (CO2) on the chemical composition, physicochemical characteristics, probiotic survival, and sensory acceptance of passion-fruit flavored whey dairy beverages (70% milk/30% whey) during storage (30 d/4°C). The addition of Lactobacillus casei and/or carbonation did not impact on the chemical composition, pH values, and acceptance (flavor and overall impression) of the products, but increased the acidity, and decreased the aroma acceptance. The carbonation process did not affect the probiotic survival but decreased the acidity of the products during storage. It can be concluded that it is possible to develop a probiotic passion-fruit flavored carbonated whey dairy beverage with suitable chemical composition, acidity, sensory acceptance (>6 in 9-point hedonic scale) and probiotic viability (>7 log cfu/ml) that could be refrigerated stored for 30 d. This is the first report considering a probiotic non-fermented carbonated whey dairy beverage.


Subject(s)
Carbonated Beverages/analysis , Carbonated Beverages/microbiology , Lacticaseibacillus casei/physiology , Milk/chemistry , Milk/microbiology , Probiotics/administration & dosage , Animals , Chemical Phenomena , Food Storage/methods , Fruit , Hydrogen-Ion Concentration , Passiflora , Refrigeration , Smell , Whey/chemistry , Whey/microbiology
2.
Am J Trop Med Hyg ; 103(1): 249-252, 2020 07.
Article in English | MEDLINE | ID: mdl-32274989

ABSTRACT

Burkholderia pseudomallei and pathogenic Leptospira in contaminated drinking water can cause melioidosis and leptospirosis, respectively. Here, we evaluated their survival in beverages. We mixed six isolates (three isolates per organism) in four beverages (Coca-Cola®, Red Bull®, Singha® beer, and Gatorade®) and distilled water as the control at two final concentrations (1 × 107 colony-forming units [CFU]/mL and 1 × 103 CFU/mL). The solution was kept at two temperatures (37°C and 4°C). At 4°C and at the high concentration, pathogenic Leptospira survived in Coca-Cola® up to 3 minutes and in Singha, Red Bull®, and Gatorade up to 15 minutes, whereas B. pseudomallei survived in these beverages up to 8 hours, and 14, 14, and 28 days, respectively. The survival time of both organisms was shorter at 37°C (P = 0.01) and at the lower concentration (P = 0.001). In conclusion, Leptospira can survive in some beverages for up to 15 minutes, whereas B. pseudomallei can survive in some beverages for up to 4 weeks.


Subject(s)
Beer/microbiology , Burkholderia pseudomallei/growth & development , Carbonated Beverages/microbiology , Energy Drinks/microbiology , Leptospira/growth & development , Beverages/microbiology , Food Contamination , Isotonic Solutions , Leptospira interrogans/growth & development , Sports , Time Factors
3.
Int J Food Microbiol ; 301: 1-8, 2019 Jul 16.
Article in English | MEDLINE | ID: mdl-31048178

ABSTRACT

Yeast are usually responsible for spoilage of soft drinks and fruit beverages, because of the particular characteristics of these products (low pH, high C/N ratio). The microbial stability is guaranteed by thermal treatments. However, excessive heat treatments can affect food sensorial quality. In this work the thermal resistance of different yeasts strains (seven belonging to the species Saccharomyces cerevisiae and six belonging to the species Kluyveromyces marxianus, Zygosaccharomyces bisporus, Z. mellis, Z. rouxii, Schizosaccharomyces pombe and Saccharomycodes ludwigii) was assessed in a model system. The results showed non-linear death curves and a high variability also within the same species. The most resistant strain, belonging to the species S. cerevisiae, was chosen for further experiments in orange juice based industrial beverages: first, death curves were performed; then, the probability of beverage spoilage in relation to process parameters (initial inoculum, temperature, treatment time) was evaluated using a logistic regression model. Finally, a cross-validation was performed to investigate the predictive capability of the fitted model. Pasteurization in the soft drink industry is commonly applied according to parameters defined several decades ago, which does not consider the successive findings concerning microbial physiology and stress response, the process improvement and the more recent tools provided by predictive microbiology. In this perspective, this study can fill a gap in the literature on this subject, going to be a basis for optimizing thermal processes. In fact, the data obtained indicated an interesting possibility for food industry to better modulated (and even reduce) thermal treatments, with the aim to guarantee microbial stability while reducing thermal damage and energy costs.


Subject(s)
Carbonated Beverages/microbiology , Food Microbiology , Fruit and Vegetable Juices/microbiology , Models, Theoretical , Pasteurization , Saccharomyces cerevisiae/physiology , Citrus sinensis , Food-Processing Industry , Temperature
4.
Antonie Van Leeuwenhoek ; 111(3): 373-383, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29058139

ABSTRACT

Yeast strains and acetic acid bacteria were isolated from spoiled soft drinks with characteristic flocs as a visual defect. Polymerase chain reaction and amplification of a partial region of the LSU rRNA gene identified the bacteria as Asaia spp. Sequence analysis of the D1/D2 region of the 26S rDNA in turn identified the yeast isolates as Wickerhamomyces anomalus, Dekkera bruxellensis and Rhodotorula mucilaginosa. The hydrophobicity and adhesion properties of the yeasts were evaluated in various culture media, taking into account the availability of nutrients and the carbon sources. The highest hydrophobicity and best adhesion properties were exhibited by the R. mucilaginosa cells. Our results suggest that Asaia spp. bacterial cells were responsible for the formation of flocs, while the presence of yeast cells may help to strengthen the structure of co-aggregates.


Subject(s)
Acetic Acid/metabolism , Bacteria/classification , Bacteria/metabolism , Carbonated Beverages/microbiology , Food Microbiology , Microbial Consortia , Yeasts/classification , Bacteria/growth & development , Bacterial Adhesion , Biofilms , Yeasts/chemistry , Yeasts/growth & development
5.
Food Res Int ; 102: 111-118, 2017 12.
Article in English | MEDLINE | ID: mdl-29195929

ABSTRACT

The absence of the yeast protein seripauperin 5 (PAU5) from Saccharomyces cerevisiae has been suggested as a biomarker for the occurrence of gushing in sparkling wine as samples lacking PAU5 were found to be more susceptible to gushing. In this study, further characterization of PAU5 regarding its foam-stabilizing properties was performed to elucidate whether PAU5 has foam-stabilizing properties and therefore, to elucidate a direct influence on the gushing potential of sparkling wines. PAU5 was successfully purified from non-gushing sparkling wine using reversed-phase high-performance liquid chromatography (RP-HPLC). Pure protein was added to grape juice as a model system for grape must prior to foam stability testing. The results revealed that the protein PAU5 has foam-stabilizing properties. Furthermore, the influence of heat and sulfur treatment in the presence of Botrytis cinerea was analyzed with regard to the amount of PAU5 produced by S. cerevisiae fermented in grape juice. Fermentation experiments using two different S. cerevisiae strains were performed, and the concentration of PAU5 in the samples was compared by RP-HPLC analysis. Unlike sulfur treatment, heat treatment prevented the protein degradation induced by B. cinerea and resulted in even higher amounts of PAU5 compared to the juice fermented with yeast without a previous botrytization. The two different yeast strains applied secreted PAU5 into the surrounding medium in different amounts. In further experiments, the fining process of the wine with bentonite was examined for its potential to remove PAU5 from the wine. RP-HPLC of wines processed with different fining agents revealed that bentonite treatment affected PAU5 concentrations in the final product. The extent of PAU5 removal depended on the type of bentonite applied and on the time of addition during the production process.


Subject(s)
Carbonated Beverages/microbiology , Excipients/metabolism , Fermentation , Food Microbiology/methods , Fruit/microbiology , Membrane Proteins/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Vitis/microbiology , Wine/microbiology , Bentonite/chemistry , Botrytis/metabolism , Chromatography, High Pressure Liquid , Chromatography, Reverse-Phase , Protein Stability , Temperature
6.
Food Microbiol ; 67: 17-22, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28648289

ABSTRACT

This study aimed to evaluate the levels of enteric bacteria in ice cubes produced in different environments (home-made, prepared in bars and pubs with ice machines and produced in industrial plants) and to determine their survival in different alcoholic beverages and soft drinks. Members of the Enterobacteriaceae family were found in almost all samples analysed. All industrial and the majority of home-made samples did not contain coliforms. Enterococci were not identified in domestic samples while they were detected in two industrial and three bar/pub samples. The samples collected from bars and pubs were characterized by the highest levels of enteric bacteria. Fourteen strains representing 11 species of eight bacterial genera were identified, some of which are known agents of human infections. The most numerous groups included Enterococcus and Stenotrophomonas. The survival of Enterococcus faecium ICE41, Pantoea conspicua ICE80 and Stenotrophomonas maltophilia ICE272, that were detected at the highest levels (100-400 CFU/100 mL thawed ice) in the ice cubes, was tested in six drinks and beverages characterized by different levels of alcohol, CO2, pH and the presence of antibacterial ingredients. The results showed a species-specific behaviour and, in general, a reduction of the microbiological risks associated with ice after its transfer to alcoholic or carbonated beverages.


Subject(s)
Alcoholic Beverages/microbiology , Carbonated Beverages/microbiology , Enterobacteriaceae/growth & development , Enterobacteriaceae/isolation & purification , Ice/analysis , Enterobacteriaceae/classification , Enterobacteriaceae/genetics , Food Contamination/analysis , Microbial Viability
7.
Biocontrol Sci ; 20(2): 99-103, 2015.
Article in English | MEDLINE | ID: mdl-26133507

ABSTRACT

In this study, a bacteriophage-based method for the colorimetric detection of E. coli O157:H7 in apple juice was investigated. Firstly, a gene encoding Cytochrome c Peroxidase (CCP) chromogenic enzyme was inserted into a wild type PP01 phage genome to construct the recombinant PP01ccp phage that was used in the production of the chromogenic enzyme through specific infection into E. coli O157:H7. The method was then examined in the colorimetric detection of E. coli O157:H7 in broth, and the appearance of E. coli O157:H7 in broth was confirmed by the color change after a few minutes of the enzyme assay. Secondly, the method was investigated in the colorimetric detection of E. coli O157:H7 in apple juice. A low E. coli O157:H7 concentration as 1 CFU mL(-1) was detected in 15 h that was in a shorter time than in previous bioluminescence phage-based methods. Moreover, the method is much simpler compared to other previous phage-based methods since it enables detection without the need for expensive apparatus.


Subject(s)
Bacteriological Techniques/methods , Bacteriophages/genetics , Carbonated Beverages/microbiology , Colorimetry/methods , Escherichia coli O157/isolation & purification , Escherichia coli O157/virology , Food Microbiology/methods , Bacteriophages/growth & development , Cytochrome-c Peroxidase/analysis , Cytochrome-c Peroxidase/genetics , Genes, Reporter , Genome, Viral , Malus , Recombination, Genetic , Sensitivity and Specificity , Time Factors
8.
Appl Microbiol Biotechnol ; 99(21): 9123-34, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26135985

ABSTRACT

Recent studies have suggested a correlation between genotype groups of Brettanomyces bruxellensis and their source of isolation. To further explore this relationship, the objective of this study was to assess metabolic differences in carbon and nitrogen assimilation between different B. bruxellensis strains from three beverages, including beer, wine, and soft drink, using Biolog Phenotype Microarrays. While some similarities of physiology were noted, many traits were variable among strains. Interestingly, some phenotypes were found that could be linked to strain origin, especially for the assimilation of particular α- and ß-glycosides as well as α- and ß-substituted monosaccharides. Based upon gene presence or absence, an α-glucosidase and ß-glucosidase were found explaining the observed phenotypes. Further, using a PCR screen on a large number of isolates, we have been able to specifically link a genomic deletion to the beer strains, suggesting that this region may have a fitness cost for B. bruxellensis in certain fermentation systems such as brewing. More specifically, none of the beer strains were found to contain a ß-glucosidase, which may have direct impacts on the ability for these strains to compete with other microbes or on flavor production.


Subject(s)
Brettanomyces/genetics , Brettanomyces/physiology , Carbon/metabolism , Genetic Variation , Metabolic Networks and Pathways/genetics , Nitrogen/metabolism , Beer/microbiology , Brettanomyces/classification , Brettanomyces/isolation & purification , Carbonated Beverages/microbiology , DNA, Fungal/genetics , Genomics , Genotype , Phenotype , Polymerase Chain Reaction , Sequence Deletion , Wine/microbiology , alpha-Glucosidases/genetics , alpha-Glucosidases/metabolism , beta-Glucosidase/genetics , beta-Glucosidase/metabolism
9.
PLoS One ; 10(3): e0119131, 2015.
Article in English | MEDLINE | ID: mdl-25748027

ABSTRACT

The anaerobic packed-bed (AP) and hybrid packed-bed (HP) reactors containing methanogenic microbial consortia were applied to treat synthetic soft drink wastewater, which contains polyethylene glycol (PEG) and fructose as the primary constituents. The AP and HP reactors achieved high COD removal efficiency (>95%) after 80 and 33 days of the operation, respectively, and operated stably over 2 years. 16S rRNA gene pyrotag analyses on a total of 25 biofilm samples generated 98,057 reads, which were clustered into 2,882 operational taxonomic units (OTUs). Both AP and HP communities were predominated by Bacteroidetes, Chloroflexi, Firmicutes, and candidate phylum KSB3 that may degrade organic compound in wastewater treatment processes. Other OTUs related to uncharacterized Geobacter and Spirochaetes clades and candidate phylum GN04 were also detected at high abundance; however, their relationship to wastewater treatment has remained unclear. In particular, KSB3, GN04, Bacteroidetes, and Chloroflexi are consistently associated with the organic loading rate (OLR) increase to 1.5 g COD/L-d. Interestingly, KSB3 and GN04 dramatically decrease in both reactors after further OLR increase to 2.0 g COD/L-d. These results indicate that OLR strongly influences microbial community composition. This suggests that specific uncultivated taxa may take central roles in COD removal from soft drink wastewater depending on OLR.


Subject(s)
Bacteria, Anaerobic/classification , Bacteria, Anaerobic/isolation & purification , Bioreactors/microbiology , Carbonated Beverages/microbiology , Wastewater/microbiology , Anaerobiosis , Bacteria, Anaerobic/genetics , DNA, Bacterial/analysis , DNA, Ribosomal/analysis , Microbial Consortia , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/analysis , Sequence Analysis, DNA , Waste Disposal, Fluid/methods
10.
Biomed Res Int ; 2015: 128697, 2015.
Article in English | MEDLINE | ID: mdl-25695045

ABSTRACT

Soft drinks consumption is still a controversial issue for public health and public policy. Over the years, numerous studies have been conducted into the possible links between soft drink intake and medical problems, the results of which, however, remain highly contested. Nevertheless, as a result, increasing emphasis is being placed on the health properties of soft drinks, by both the industry and the consumers, for example, in the expanding area of functional drinks. Extensive legislation has been put in place to ensure that soft drinks manufacturers conform to established national and international standards. Consumers trust that the soft drinks they buy are safe and their quality is guaranteed. They also expect to be provided with information that can help them to make informed decisions about the purchase of products and that the information on product labels is not false or misleading. This paper provides a broad overview of available scientific knowledge and cites numerous studies on various aspects of soft drinks and their implications for health safety. Particular attention is given to ingredients, including artificial flavorings, colorings, and preservatives and to the lesser known risks of microbiological and chemical contamination during processing and storage.


Subject(s)
Carbonated Beverages/adverse effects , Carbonated Beverages/microbiology , Animals , Food/adverse effects , Food Coloring Agents/adverse effects , Food Microbiology , Food Preservatives/adverse effects , Health , Humans , Product Packaging , Safety
11.
J Food Sci ; 79(3): M391-8, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24673374

ABSTRACT

UNLABELLED: The antimicrobial effects of 2 terpenes (citral and linalool) on a Saccharomyces cerevisiae strain isolated from spoiled soft drink have been evaluated, alone or in combination, in relation to pH and aw using in vitro assays. The obtained data were fitted with the logit model to find the growth/no growth boundary regions of the 2 terpenes, focusing the attention on the type of interaction exerted by citral and linalool. In particular, the results showed an increase of citral antimicrobial effect in growth media characterized by low aw value, as well as a higher linalool antimicrobial effect in media at low pH. Moreover, the interactive effects of the 2 terpenes were exploited. The results obtained with the model were validated in an independent experiment. The knowledge of the interactions of essential oil molecules with enhanced antimicrobial activity, in relation to some of the most important chemicophysical variables, can have important industrial applications, since these substances are able to assure the desired antimicrobial effect without negatively modifying the product flavor profile. PRACTICAL APPLICATION: The effects of the main chemicophysical parameters (such as aw and pH) on the antimicrobial activity of bioactive terpenes are necessary for the definition of an industrially applicable preservation strategy based on the use of essential oils as natural antimicrobials aimed to prolong shelf life of food products.


Subject(s)
Anti-Infective Agents/pharmacology , Food Microbiology , Food Preservation , Monoterpenes/pharmacology , Oils, Volatile/pharmacology , Saccharomyces cerevisiae/growth & development , Acyclic Monoterpenes , Carbonated Beverages/microbiology , Humans , Hydrogen-Ion Concentration , Logistic Models , Saccharomyces cerevisiae/isolation & purification , Taste , Terpenes/pharmacology
12.
J Food Sci ; 79(4): M604-13, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24592938

ABSTRACT

Drinkable yogurt is a popular beverage in the United States and there may be a niche for carbonated drinkable yogurt in the functional foods market. Pomegranate (P) and vanilla (V) yogurt beverages were formulated, containing inulin as a prebiotic, along with probiotic bacteria Lactobacillus acidophilus and Bifidobacterium, to produce symbiotic products. These beverages were stabilized with high-methoxyl pectin and whey protein concentrate and compared to samples with approximately 2 volumes of added carbon dioxide (CO2 ). Samples were stored in sealed glass bottles at 4 °C for 9 wk for evaluation of physicochemical and functional properties. Trials were carried out in triplicate and 3 replicates from each trial were analyzed. Physicochemical attributes were analyzed using standard AOAC methods. Survivability of the probiotics and changes in pH and viscosity were measured weekly. Chemical composition of the carbonated beverages was: protein: 1.58 ± 0.05%, 1.59 ± 0.06%, fat: 1.24 ± 0.2%, 1.18 ± 0.11%, total solids: 14.78 ± 0.11%, 14.93 ± 0.05%, ash: 0.49 ± 0.02%, 0.46 ± 0.03%, and carbohydrate (by difference): 11.47 ± 0.12%, 11.69 ± 0.14% for P and V, respectively. Both L. acidophilus and Bifidobacterium were stable and remained above 10(6) CFU/g for both flavors of beverage both with and without carbonation. The new manufacturing technology for these prototypes may have potential for commercialization of carbonated symbiotic milk-based beverages.


Subject(s)
Bifidobacterium/drug effects , Carbon Dioxide/pharmacology , Carbonated Beverages/analysis , Lactobacillus acidophilus/drug effects , Milk/microbiology , Probiotics , Yogurt/analysis , Animals , Carbonated Beverages/microbiology , Humans , Hydrogen-Ion Concentration , Inulin , Milk Proteins , Prebiotics , Synbiotics , Taste , Viscosity , Whey Proteins , Yogurt/microbiology
13.
J Agric Food Chem ; 61(50): 12362-73, 2013 Dec 18.
Article in English | MEDLINE | ID: mdl-24308669

ABSTRACT

The evolution in polysaccharide composition and molecular weights during sparkling wine making and aging was studied for the first time in this work. Different autochthonous grape varieties from Spain (Verdejo, Viura, Malvasía, Albarín, Godello, Garnacha and Prieto Picudo) were used to elaborate sparkling wines following the champenoise method. Principal component analysis showed differentiation of wines according to polysaccharide families. This differentiation was due to the process of aging on yeast lees, but not to the variety employed. The content of mannoproteins during aging was positively correlated (r = 0.792) with total polysaccharides from grapes. After six months of aging the highest content of mannoproteins and polysaccharides rich in arabinose and galactose was obtained. Also a shift to lower molecular weights was observed. The combination of these two characteristics could imply a better foam stability and thus sensory quality of sparkling wines.


Subject(s)
Carbonated Beverages/analysis , Polysaccharides/chemistry , Saccharomyces cerevisiae/metabolism , Vitis/microbiology , Carbonated Beverages/microbiology , Fermentation , Polysaccharides/metabolism , Time Factors , Vitis/chemistry , Vitis/metabolism
14.
Int J Food Microbiol ; 163(2-3): 218-22, 2013 May 15.
Article in English | MEDLINE | ID: mdl-23562835

ABSTRACT

Few studies have examined patterns of microbial contamination in soda fountain beverages. In this study, patterns of microbial contamination in beverages dispensed from soda fountain machines (SFMs) sampled in June 2009 and then again 13 months later were compared. Over 70% of beverages contained microbes in both years, suggesting that contamination of beverages dispensed from SFMs can continue for long periods of time. In addition, the impact of disinfecting the dispensing nozzles and plastic tubing of SFMs, as well as the impact of machine use on microbial contamination was assessed. Managers from 26 establishments (fast-food and convenience stores) were interviewed about their SFM disinfecting practices and no correlation was found between the self-reported disinfecting practices and levels of microbial contamination in beverages dispensed from SFMs. Furthermore, in a direct study of two SFMs with an established disinfecting regimen, CFU/mL in beverages increased significantly immediately after disinfecting of plastic tubing yet returned to pre-disinfecting concentrations within 11 days. These results suggest that disinfecting may disturb microbial communities, resulting in increased planktonic microbes, but not the ultimate removal of communities themselves. Additionally, samples of a sugar and a diet soda were collected from 15 different SFMs before and after dispensing of ~0.95 L (the approximate size of a large beverage cup). Samples collected before dispensing this volume had significantly higher microbial counts than those collected after, suggesting that planktonic microbes in the beverage lines had been reduced by flushing. As there are currently no regulations regarding the disinfecting of SFM tubing or periodic inspections of beverages dispensed from SFMs, it would be valuable for consumers to encourage increased surveillance of SFMs, and to dispense some beverage before filling their cups.


Subject(s)
Carbonated Beverages/microbiology , Disinfection/standards , Food Handling/instrumentation , Food Microbiology , Longitudinal Studies , Time Factors
15.
J Food Prot ; 76(1): 72-8, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23317859

ABSTRACT

This study was conducted to evaluate the effectiveness of natural antimicrobials for shelf-life extension of cold-filled still and carbonated Concord and Niagara grape juices, which have traditionally been preserved with chemical preservatives. Commercial juices were inoculated with a spoilage yeast cocktail of Dekkera, Kluveromyces, Brettanomyces, and Zygosaccharomyces at 10(2) and 10(4) CFU/ml. The following agents were added to still juices: no preservative (negative control), 0.05% potassium sorbate plus 0.05% sodium benzoate (positive control), 0.1 or 0.2% cultured dextrose, 250 ppm of dimethyldicarbonate (DMDC), 10 or 20 ppm of natamycin, and 250 ppm of DMDC plus 5 or 10 ppm of natamycin. Carbonated juice was treated with the negative control, positive control, and 250 ppm of DMDC plus 10 ppm of natamycin. Microbial stability of samples was assessed every 2 weeks during 6 months of storage at 21°C by yeast enumeration and measurement of turbidity, pH, and °Brix. Juices were deemed spoiled when yeast counts exceeded 10(6) CFU/ml. Cultured dextrose was not effective at levels tested in both types of juice. The most promising results were obtained with DMDC and natamycin combination treatments in still Niagara juice and in carbonated Concord and Niagara juices. In these treatments, shelf-life extension similar to that of the positive control (153 to 161 days) was achieved while maintaining similar turbidity, pH, and °Brix. Spoiled juices had lower pH and °Brix values and higher turbidity due to microbial activity and increased in microbial levels.


Subject(s)
Beverages/microbiology , Food Contamination/prevention & control , Food Preservation/methods , Food Preservatives/pharmacology , Yeasts/drug effects , Yeasts/growth & development , Carbonated Beverages/microbiology , Colony Count, Microbial , Consumer Product Safety , Dose-Response Relationship, Drug , Food Contamination/analysis , Humans , Hydrogen-Ion Concentration , Microbial Sensitivity Tests , Time Factors , Vitis/microbiology
16.
Adv Food Nutr Res ; 61: 1-55, 2010.
Article in English | MEDLINE | ID: mdl-21092901

ABSTRACT

The so-called effervescence process, which enlivens champagne, sparkling wines, beers, and carbonated beverages in general, is the result of the fine interplay between CO2-dissolved gas molecules, tiny air pockets trapped within microscopic particles during the pouring process, and some liquid properties. This chapter summarizes recent advances obtained during the last decade concerning the physicochemical processes behind the nucleation, rise, and burst of bubbles found in glasses poured with sparkling beverages. Those phenomena observed in close-up through high-speed photography are often visually appealing. Moreover, the kinetics of gas discharging from freshly poured glasses was monitored with time, whether champagne is served into a flute or into a coupe. The role of temperature was also examined. We hope that your enjoyment of champagne will be enhanced after reading this fully illustrated review dedicated to the deep beauties of nature often hidden behind many everyday phenomena.


Subject(s)
Carbonated Beverages/analysis , Wine/analysis , Carbon Dioxide/analysis , Carbon Dioxide/chemistry , Carbonated Beverages/microbiology , Fermentation , Models, Chemical , Phase Transition , Wine/microbiology
17.
Int J Food Microbiol ; 141(1-2): 110-5, 2010 Jun 30.
Article in English | MEDLINE | ID: mdl-20442005

ABSTRACT

The class II hydrophobin FcHyd5p from Fusarium culmorum was heterologously expressed by Pichia pastoris. Transcription of the recombinant gene was confirmed by RT-PCR and expression of FcHyd5p was demonstrated using SDS-PAGE and immuno-staining with 6 x His-tag antibodies. FcHyd5p was purified and concentrated by dialysis, isoelectric focussing and the use of ultra filtration. It was demonstrated that FcHyd5p is able to change the hydrophopic properties of surfaces rendering them wettable after coating with the supernatant of recombinant P. pastoris cultures. Furthermore, due to its surface activity, FcHyd5p was able to stabilise air bubbles in aqueous solutions. The supernatant of a culture medium containing a FcHyd5p producing P. pastoris clone remained turbid for 24h and the foam stable for more than 72 h after the treatment with a homogeniser, whereas the liquid of the wild type strain clarified after 10 min and the foam disintegrated after 2h. Finally it was demonstrated, that FcHyd5p can induce spontaneous overfoaming of carbonated liquids, referred to as gushing. Addition of 2 mg freeze-dried culture supernatant from a FcHyd5p producing P. pastoris clone resulted in a lost volume of 252 ml +/- 20 per 500 ml of beer (50%) and 179 ml +/- 7 per 330 ml of carbonated water (54%), respectively. Neither untreated beer/water, nor beer/water treated with freeze-dried culture supernatant from the wild type strain showed any gushing. Furthermore, addition of 215 microg highly purified FcHyd5p resulted in a lost volume of 77 ml +/- 40 per 500 ml beer (15%).


Subject(s)
Carbonated Beverages/microbiology , Food Microbiology , Fungal Proteins , Fusarium/genetics , Hydrophobic and Hydrophilic Interactions , Pichia , Recombinant Proteins , Beer , Cloning, Molecular , Electrophoresis, Polyacrylamide Gel , Fungal Proteins/chemistry , Fungal Proteins/genetics , Fungal Proteins/isolation & purification , Fungal Proteins/metabolism , Gene Expression , Genes, Fungal , Pichia/genetics , Pichia/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Water
18.
Int J Food Microbiol ; 137(1): 61-6, 2010 Jan 31.
Article in English | MEDLINE | ID: mdl-19926155

ABSTRACT

Ninety beverages of three types (sugar sodas, diet sodas and water) were obtained from 20 self-service and 10 personnel-dispensed soda fountains, analyzed for microbial contamination, and evaluated with respect to U.S. drinking water regulations. A follow-up study compared the concentration and composition of microbial populations in 27 beverages collected from 9 soda fountain machines in the morning as well as in the afternoon. Ice dispensed from these machines was also examined for microbial contamination. While none of the ice samples exceeded U.S. drinking water standards, coliform bacteria was detected in 48% of the beverages and 20% had a heterotrophic plate count greater than 500cfu/ml. Statistical analyses revealed no difference in levels of microbial contamination between beverage types or between those dispensed from self-service and personnel-dispensed soda fountains. More than 11% of the beverages analyzed contained Escherichia coli and over 17% contained Chryseobacterium meningosepticum. Other opportunistic pathogenic microorganisms isolated from the beverages included species of Klebsiella, Staphylococcus, Stenotrophomonas, Candida, and Serratia. Most of the identified bacteria showed resistance to one or more of the 11 antibiotics tested. These findings suggest that soda fountain machines may harbor persistent communities of potentially pathogenic microorganisms which may contribute to episodic gastric distress in the general population and could pose a more significant health risk to immunocompromised individuals. These findings have important public health implications and signal the need for regulations enforcing hygienic practices associated with these beverage dispensers.


Subject(s)
Carbonated Beverages/microbiology , Enterobacteriaceae/isolation & purification , Food Microbiology , Carbonated Beverages/adverse effects , Carbonated Beverages/standards , Chryseobacterium/isolation & purification , Colony Count, Microbial , Drug Resistance, Bacterial , Escherichia coli/isolation & purification , Food Contamination , Food Microbiology/standards , Humans , Ice/standards , Public Health/standards , United States , Water Microbiology/standards
19.
J Food Prot ; 72(12): 2607-10, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20003747

ABSTRACT

This study was undertaken to evaluate the microbial quality of the soft drinks served by fast food restaurants and gas station convenience stores in Griffin, GA, and surrounding areas. The soft drinks were collected from the dispensing machines in 8 fast food restaurants or gas station convenience stores in 2005 (n = 25) and in 10 fast food restaurants or gas station convenience stores in 2006 (n = 43) and 2007 (n = 43). One hundred milliliters of each soft drink was filtered through a hydrophobic grid membrane filter. The remaining portion of the soft drink was kept at room temperature for 4 h before sampling in order to mimic the possible holding time between purchase and consumption. The membrane filters were sampled for total aerobic bacteria, Enterobacteriaceae, lactic acid bacteria, and yeasts and molds. The microbial counts in the 2006 samples were numerically higher than the counts in the 2007 samples except for the average lactic acid bacteria counts, and were either significantly or numerically higher than the counts in the 2005 samples. Soft drinks sampled after the 4-h holding period had relatively higher counts than those sampled initially, with a few exceptions. Some soft drinks had over 4 log CFU/100 ml of total aerobic bacteria, Enterobacteriaceae, lactic acid bacteria, and yeast and mold cells. The study revealed the microbial quality of soft drinks served by dispensing machines in Griffin, GA, and surrounding areas, emphasizing the importance of effective sanitizing practice in retail settings.


Subject(s)
Bacteria/isolation & purification , Carbonated Beverages/microbiology , Food Microbiology , Fungi/isolation & purification , Georgia , Restaurants
20.
Int J Food Microbiol ; 130(2): 156-8, 2009 Mar 31.
Article in English | MEDLINE | ID: mdl-19232446

ABSTRACT

A total of 225 carbonated soft drink (CSD) samples from nine brands, from various locations in five metropolitan cities of Bangladesh were examined to determine their bacteriological quality. Most samples were not in compliance with microbiological standards set by organizations like the World Health Organization (WHO). Pseudomonas aeruginosa was the predominant species with an incidence of 95%. Streptococcus spp. and Bacillus stearothermophilus were the next most prevalent with numbers ranging from 6 to 122 and 9 to 105 cfu/100 ml, respectively. Fifty four percent of the samples yielded Salmonella spp. at numbers ranging from 2 to 90 cfu/100 ml. Total coliform (TC) and faecal coliform (FC) counts were found in 68-100% and 76-100% of samples of individual brands, at numbers ranging from 5 to 213 and 3 to 276 cfu/100 ml, respectively. According to WHO standards 60-88% of samples from six brands and 32% and 40% of samples from two other brands belonged to the intermediate risk group with FC counts of 100-1000 cfu/100 ml. Heterotrophic plate counts, however, were under the permissible limit in all 225 samples. These findings suggest that carbonated soft drinks commercially available in Bangladesh pose substantial risks to public health.


Subject(s)
Bacteria/isolation & purification , Carbonated Beverages/microbiology , Food Microbiology , Bacteria/classification , Bangladesh
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