Wet fermentation of Coffea canephora by lactic acid bacteria and yeasts using the self-induced anaerobic fermentation (SIAF) method enhances the coffee quality.

This work aimed to evaluate the impact of inoculation single and co-cultivation of LAB and yeasts during the wet process of Coffea canephora using the self-induced anaerobic fermentation method. Saccharomyces cerevisiae, Totulaspora delbrueckii delbrueckii, Leuconostoc mesenteroides, and Lactiplantibacillus plantarum were monitored during fermentation. L. mesenteroides was detected in high concentrations in the coffee fruits (8.54 log10 cells/mL) and remained until the end of fermentation. Lactic and acetic acids were the main acids produced during fermentation. After 36 h of fermentation, 75.39% of malic acid was consumed in the L. mesenteroides + S. cerevisiae (MC) fermentations. In roasted coffee, the caffeine concentration reached 3.29 higher than the green beans in MC fermentation. Specific volatile compounds were detected in inoculated fermentation and may contribute to the beverage quality. Coffee inoculated with Leuconostoc mesenteroides was classified as fine (80.0-89.0), while the other fermentations were classified as premium (70.0-79.0). L. mesenteroides inoculation showed the best sensory score, and the beverage was characterized by caramel, fruity, and spices notes. L. mesenteroides inoculated alone or in co-culture with S. cerevisiae are promising starter cultures to improve Conilon coffee quality and obtain beverages with differentiated sensory profiles.

Ultrasound, Acetic Acid, and Peracetic Acid as Alternatives Sanitizers to Chlorine Compounds for Fresh-Cut Kale Decontamination.

Chlorinated compounds are usually applied in vegetable sanitization, but there are concerns about their application. Thus, this study aimed to evaluate ultrasound (50 kHz), acetic acid (1000; 2000 mg/L), and peracetic acid (20 mg/L) and their combination as alternative treatments to 200 mg/L sodium dichloroisocyanurate. The overall microbial, physicochemical, and nutritional quality of kale stored at 7 °C were assessed. The impact on Salmonella enterica Typhimurium was verified by plate-counting and scanning electron microscopy. Ultrasound combined with peracetic acid exhibited higher reductions in aerobic mesophiles, molds and yeasts, and coliforms at 35 °C (2.6; 2.4; 2.6 log CFU/g, respectively). Microbial counts remained stable during storage. The highest reduction in Salmonella occurred with the combination of ultrasound and acetic acid at 1000 mg/L and acetic acid at 2000 mg/L (2.8; 3.8 log CFU/g, respectively). No synergistic effect was observed with the combination of treatments. The cellular morphology of the pathogen altered after combinations of ultrasound and acetic acid at 2000 mg/L and peracetic acid. No changes in titratable total acidity, mass loss, vitamin C, or total phenolic compounds occurred. Alternative treatments presented equal to or greater efficacies than chlorinated compounds, so they could potentially be used for the decontamination of kale.

Fermentation of Coffea canephora inoculated with yeasts: Microbiological, chemical, and sensory characteristics.

This work aimed to evaluate Coffea canephora's microbiological, chemical, and sensory characteristics at 300 and 600 m elevation plantations processed by the natural method inoculated with yeasts. The coffee was spread on suspended terraces and sprayed with approximately 107 cfu/mL of Meyerozyma caribbica CCMA 1738 or Pichia kluyveri CCMA 1743, separately. Cherries containing bark and parchment were collected during fermentation for microbial groups counting, qPCR, quantification of organic acids, and sugars (HPLC). Volatile compounds (GC-MS) and sensory analyses, cupping test with expert coffee tasters and triangular test with consumers, were performed on roasted coffee beans. The inoculated yeasts persisted during the entire fermentation process. M. caribbica reduced the filamentous fungal population by 63% and 90% in the 300- and 600-m coffees, respectively. The 300-m coffee fruits showed higher concentrations of organic acids in all fermentation times when compared to the 600-m reaching out to 8 times more. Twenty-four volatile compounds were identified in the roasted coffee beans, with the predominance of pyrazines. The 600-m coffee inoculated with M. caribbica showed an increase of more than one point in the score given by certified tasters. Consumers noticed the M. caribbica inoculation in the 300- and 600-m-elevation coffees. M. caribbica is a promising starter culture for Conilon coffee with the potential to increase the beverage quality.

Microbial diversity and chemical characteristics of Coffea canephora grown in different environments and processed by dry method.

This study aimed to assess the microbial diversity in Coffea canephora grown in four different environments of Espirito Santo state, Brazil. Coffee cherries of two different altitudes (300 and 600 m) and two terrain aspects (Southeast-facing and Northwest-facing slopes) were processed by the dry method. Samples were collected during the drying/fermentation process. Microorganisms were counted, isolated, and identified by MALDI-TOF, followed by sequencing of the ribosomal region. Sugars and organic acids were quantified by HPLC and volatile compounds of the roasted coffees were evaluated by GC-MS. Bacteria population presented a significant number of isolates as well as higher counts during the drying/fermentation process with respect to the population of yeasts. The principal genera of microorganisms found were Bacillus, Pichia, Candida, and Meyerozyma. Meyerozyma guilliermondii was the most frequent yeast in all environments. On the other hand, Pichia kluyveri was found only in coffee cherries from the 600 m altitude. The highest concentration of acetic and succinic acids observed was 6.06 mg/g and 0.84 mg/g, respectively. Sucrose concentrations ranged from 0.68 to 5.30 mg/g, fructose from 1.30 to 4.60 mg/g, and glucose from 0.24 to 1.25 mg/g. Thirty-six volatile compounds, belonging to the groups of pyrazines, alcohols, aldehydes, ketones, and furans were identified in roasted coffee, with differences between altitude and terrain aspects. Information about microbial diversity is crucial to better understand the coffee quality and distinct characteristics of coffee produced in different environments.

Spray-dried microcapsules of anthocyanin-rich extracts from Euterpe edulis M. as an alternative for maintaining color and bioactive compounds in dairy beverages.

Color is a sensory attribute that influences the acceptance of food and dyes are added into food products to provide them attractiveness. In this context, anthocyanins have merged as an alternative to synthetic dyes. This study aimed to develop food model systems of fermented or unfermented dairy beverages containing added microencapsulated anthocyanin-rich extracts from juçara palm fruit. The stabilities of both pigment and beverage throughout storage in opaque or transparent packaging have been evaluated. Acidity, pH and anthocyanin content in both beverages did not vary during 28 days of storage, and the content of bioactive compounds did not decrease over time. A slight overall color difference that is probably invisible to naked eyes was detected between the beverages analyzed at days 0 and 28. The potential of applying microencapsulated natural pigments into dairy matrices is an effort to increase their nutritional and sensorial values.

Combination of peracetic acid and ultrasound reduces Salmonella Typhimurium on fresh lettuce (Lactuca sativa L. var. crispa).

Salmonella outbreaks related to fruits and vegetables have been reported being lettuce one of the most contaminated. Peracetic acid (PA) at 50 mg/L, sodium dichloroisocyanurate (SD) at 100 mg/L, and the combination of SD at 100 mg/L and babaçu coconut (Attalea speciosa) oil detergent at 100 mg/L were applied to fresh lettuce. Natural contaminant microbiota, physicochemical characteristics, and sensory attributes were evaluated. PA and SD reduced mesophilic aerobic counts by 2.1 and 1.5 log cfu/g, respectively. The most efficient treatment in reducing natural microbiota (i.e., PA) was applied alone and in combination with ultrasound (US). It reduced Salmonella enterica Typhimurium counts to undetectable levels (< 1 log cfu/g). US further reduced S. Typhimurium counts by 0.6 log cfu/g in relation to PA, treatment which lessened the pH but increased the titratable acidity of lettuce, but did not cause total color difference. Therefore, the combination of PA and US holds a potential industrial application for sanitization purposes.

Modification of polysulfone membrane used in the water filtration process to reduce biofouling.

Polysulfone membranes (PSF) were modified with silver nanoparticles obtained by new synthesis (nAgNS), silver nanoparticles obtained commercially (nAgC), silver sulfadiazine (SP), dodecyltrimethylammonium bromide (DOTAB), benzalkonium chloride (CB) or sodium dodecylbenzene sulfonate (DBSS) to improve the efficiency of the water filtration process by reducing biofouling. All membranes had lower hydrophobicity compared with PSF. The zeta potentials of all membranes were negative at pH 7.0, except for CB 10%. In the agar diffusion test, E. coli was considered to be sensitive to the antimicrobial effect of the nAgNS 1%, 3%, 6%, 10% and DOTAB 10%, whereas S. aureus was sensitive to the nAgNS 1%, 3%, 6%, 10%, DOTAB 10%, CB 0.22%, 2% and 10%. The lowest adhesion of E. coli was found in the nAgNS 6% and 10%. In the evaluation of the loss of flow rate during filtration of the E. coli suspension and pure water, nAgNS showed higher flow rate values when compared with PSF. The nAgNS did not release quantities of silver (0.1 mg/l) above the amount considered safe by the World Health Organization. Membranes nAgNS 6% and 10% showed the best anti-biofouling characteristic.

Beyond brewing: ß-acid rich hop extract in the development of a multifunctional polylactic acid-based food packaging.

Hops' (Humulus lupulus L.) phytochemicals are well known for their bioactivity. In the present study, the functional properties of hop extract rich in ß-acids, as potassium-salts structures (KBA), were investigated to develop a sustainable active food packaging. Polylactic acid (PLA)-based sheets were incorporated with increasing concentrations of hop extract (0.1-5 % w/w in terms of KBA) and characterized through performance and bioactive properties. KBA-added sheets presented decreased crystallinity and affected mechanical and thermal properties, especially with higher KBA amounts. The sheets' surface hydrophobicity gradually decreased by KBA-extract addition, while the water vapor permeability was not affected. A Fickian diffuse behavior and a better fit to application in fatty foods were observed during release tests. UV-blocking and antioxidant properties were improved by KBA incorporation. Furthermore, results from antibacterial assays revealed great susceptibility of Staphylococcus aureus and Listeria monocytogenes towards sheets added with 5 % of KBA. Moreover, the atomic force microscopy (AFM) observations revealed that KBA led to strong effects on the cell membranes of both bacteria, including disruption of membrane integrity and cell death. Therefore, this study is a sign of great prospects of hop ß-acids use, as KBA compound, in the production of sustainable active packaging for safe food shelf-life extension.

Work of adhesion of dairy products on stainless steel surface.

The adhesion of the solids presents in food can difficult the process of surface cleaning and promotes the bacterial adhesion process and can trigger health problems. In our study, we used UHT whole milk, chocolate based milk and infant formula to evaluate the adhesion of Enterobacter sakazakii on stainless steel coupons, and we determine the work of adhesion by measuring the contact angle as well as measured the interfacial tension of the samples. In addition we evaluated the hydrophobicity of stainless steel after pre-conditioning with milk samples mentioned. E. sakazakii was able to adhere to stainless steel in large numbers in the presence of dairy products. The chocolate based milk obtained the lower contact angle with stainless steel surface, higher interfacial tension and consequently higher adhesion work. It was verified a tendency of decreasing the interfacial tension as a function of the increasing of protein content. The preconditioning of the stainless steel coupons with milk samples changed the hydrophobic characteristics of the surfaces and became them hydrophilic. Therefore, variations in the composition of the milk products affect parameters important that can influence the procedure of hygiene in surface used in food industry.

Chemical composition, extraction sources and action mechanisms of essential oils: Natural preservative and limitations of use in meat products.

The antimicrobial activity of essential oils (EO) is associated with the presence of secondary metabolites synthesized by plants. Its mechanism of action involves the interaction of its hydrophobic components with the lipids present in the cell membrane of microorganism, resulting in metabolic damages and cell death. Spoilage and pathogenic microorganisms are contaminants in meat and meat products with considerable impacts on food quality and safety. Research shows the potential of applying essential oils in the preservation of meat food systems as compounds of low toxicity, extracted from a natural source, and as an alternative to consumer demand for healthy foods with a more natural appeal. In addition, there is a great diversity of plants from which essential oils can be extracted, whose antimicrobial activity in vitro and in meat and meat products has been proven.

Assessment of hydrophobicity and roughness of stainless steel adhered by an isolate of Bacillus cereus from a dairy plant.

The interaction between the surface of stainless steel and Bacillus cereus was studied in terms of the characteristics of interfacial interaction determined from the measurement of the contact angle of the surface of B. cereus and stainless steel in the presence or absence of B. cereus adherence. The microtopographies and the roughness of the surface of stainless steel and stainless steel adhered by B. cereus were evaluated with the help of atomic force microscopy and perfilometry. The strain of B. cereus studied was considered hydrophilic, whereas the stainless steel was considered hydrophobic. The adhesion was not thermodynamically favorable (ΔGadhesion > 0) between the stainless steel and the strain of B. cereus studied. Thus, the interaction between them was not favored by the thermodynamic aspect of adhesion. There was no difference (p > 0.05) in the roughness of the surfaces of stainless steel adhered by B. cereus when analyzed by atomic force microscope and perfilometry.

Increased presevation of sliced mozzarella cheese by antimibrobial sachet incorporated with allyl isothiocyanate.

There is an increasing tendency to add natural antimicrobials of plant origin into food. The objective of this work was to develop a microbial sachet incorporated with allyl isothiocyanate (AIT), a volatile compound of plant origin, and to test its efficiency against growth of yeasts and molds, Staphylococcus sp. and psychrotrophic bacteria on sliced mozzarella cheese. Another objective was to quantify the concentration of AIT in the headspace of cheese packaging. A reduction of 3.6 log cycles was observed in yeasts and molds counts in the mozzarella packed with the antimicrobial sachet over 15-day storage time. The sachet also showed an antibacterial effect on Staphylococcus sp., reducing 2.4 log cycles after 12-day storage. Psychrotrophic bacteria species were the most resistant to the antimicrobial action. The highest concentration of AIT (0.08µg.mL(-1)) inside the active packaging system was observed at the 6(-)day of storage at 12 ºC ± 2 ºC. At the end of the storage time, AIT concentration decreased to only 10% of the initial concentration. Active packaging containing antimicrobial sachet has a potential use for sliced mozzarella, with molds and yeasts being the most sensitive to the antimicrobial effects.

ß-Cyclodextrin inclusion complexes with essential oils: Obtention, characterization, antimicrobial activity and potential application for food preservative sachets.

The current study aimed obtaining antimicrobial sachets that could be used as preservatives for foods. Basil (BEO) and Pimenta dioica (PDEO) essential oils (EOs) were analyzed by GC-FID and GC-MS and tested against the foodborne bacteria S. aureus, E. coli, L. monocytogenes, P. aeruginosa, S. Enteritidis, and the food-spoilage mold B. nivea. Then, inclusion complexes (ICs) with EOs and ß-cyclodextrin (ß-CD) were prepared as a strategy to reduce volatility and increase the release time of EOs. Eight ICs were prepared by kneading and freeze-drying methods, in two molar ratios, and have been characterized by complementary methods: FT-IR, thermal analysis (DSC and TG/DTG), powder XRD, and solid state 13C NMR. In vitro antimicrobial activities of ICs, both dispersed in agar and loaded in sachets, have also been investigated. Complexation was confirmed for all samples. PDEO-based ICs prepared by kneading method, at both molar ratios, displayed better in vitro antimicrobial activity. The obtained results strongly suggest a potential application of these ICs as natural antimicrobials.

Semisynthetic Phenol Derivatives Obtained from Natural Phenols: Antimicrobial Activity and Molecular Properties.

Semisynthetic phenol derivatives were obtained from the natural phenols: thymol, carvacrol, eugenol, and guaiacol through catalytic oxychlorination, Williamson synthesis, and aromatic Claisen rearrangement. The compounds characterization was carried out by 1H NMR, 13C NMR, and mass spectrometry. The natural phenols and their semisynthetic derivatives were tested for their antimicrobial activity against the bacteria: Staphylococcus aureus, Escherichia coli, Listeria innocua, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Salmonella enterica ssp. enterica, and Bacillus cereus. Minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were determined using concentrations from 220 to 3.44 µg mL-1. Most of the tested compounds presented MIC values ≤220 µg mL-1 for all the bacteria used in the assays. The molecular properties of the compounds were computed with the PM6 method. Through principle components analysis, the natural phenols and their semisynthetic derivatives with higher antimicrobial potential were grouped.

Ultrasound improves antimicrobial effect of sodium dichloroisocyanurate to reduce Salmonella Typhimurium on purple cabbage.

The consumer's interest in ready-to-eat, fast-ready, nutritious and fresh foods is a major challenge for the food industry. Thus, studies on new sanitization methods are relevant. The effect of Sodium Hypochlorite (SH), Benzalkonium Chloride (BC), and Sodium Dichloroisocyanurate (SD) isolated or combined with Ultrasound (US) in purple cabbage quality over 7 days of storage at 8 ±â€¯1 °C was evaluated. The natural microbiota (mesophilic aerobic bacteria, lactic acid bacteria and coliforms), intentionally inoculated Salmonella Typhimurium, physicochemical quality (anthocyanins, pH, total titratable acidity, instrumental color and mass loss) and sensorial quality (multiple comparison test and visual sensory acceptance) were analyzed. The best treatments for natural microbiota reduction were BC and US + BC, which in general reduced between 1.9 and 3.2 log cfu/g. US improved (p < .05) the effect of SD reducing almost 4 log cycles in the population of S. Typhimurium adhered to cabbage. The treatments with benzalkonium chloride resulted in important physicochemical changes in cabbage. The treatments SD and US + SD did not alter the physicochemical and sensorial characteristics of purple cabbage. Therefore, ultrasound combined with sodium dichloroisocyanurate is a promising alternative for the reduction of microbiological contaminants of purple cabbage without physicochemical, sensory and anthocyanin content loss.

Ultrasound improves chemical reduction of natural contaminant microbiota and Salmonella enterica subsp. enterica on strawberries.

New sanitization methods have been evaluated to improve food safety and food quality and to replace chlorine compounds. However, these new methods can lead to physicochemical and sensory changes in fruits and vegetables. The present study evaluated the effects of acetic acid, peracetic acid, and sodium dodecylbenzenesulfonate isolated or combined with 5min of ultrasound treatment (40kHz, 500W) on strawberry quality over 9days of storage at 8°C. The strawberry natural contaminant microbiota (molds and yeasts, mesophilic aerobic and lactic acid bacteria), physicochemical quality (pH, total titratable acidity, total soluble solids, vitamin C, and color), sensory quality (triangle test) and inactivation of Salmonella enterica subsp. enterica intentionally inoculated onto strawberries were analyzed. Ultrasound increased the effect of all chemical compounds in the reduction of aerobic mesophilic, molds and yeasts. The best treatment for those groups of microorganisms was ultrasound combined with peracetic acid (US+PA) that reduced 1.8 and 2.0logcfu/g during 9days of storage. Bactericidal effect of peracetic acid was also improved by ultrasound inactivation of S. enterica, reaching a decimal reduction of 2.1logcfu/g. Moreover, synergistic effects were observed in contaminant natural microbiota inactivation for all tested compounds during storage, without any major physicochemical or sensory alteration to the strawberries. Therefore, ultrasound treatment can improve the effect of sanitizers that are substitutes of chlorine compounds without altering the quality of strawberries during storage. Acetic acid (PubChem CID: 176); Peracetic acid (PubChem CID: 6585); Sodium dodecylbenzenesulfonate (PubChem CID: 18372154).

Removal of Salmonella enterica Enteritidis and Escherichia coli from green peppers and melons by ultrasound and organic acids.

The aim of this study was to evaluate the effectiveness of ultrasound treatment combined with organic acids in the decontamination step for green peppers and melons. The influence of the surface roughness of the peppers and melons on bacterial adhesion was evaluated, as measured using a profilometer. The adhesion of Salmonella enterica serovar Enteritidis and Escherichia coli to the green pepper and melon surfaces was also evaluated by measuring the hydrophobicity of the microorganisms and the surfaces. The bacteria that adhered to the surface of green peppers and melons was quantified by plate count and visualized by scanning electron microscopy. In addition, the efficiency of ultrasound and organic acids to remove bacteria from the pepper and melon surfaces was examined. The average roughness (Ra) of the green peppers (13.0±2.7 nm) was significantly different (p>0.05) from the melons (33.5±7.9 nm). Adherence of S. Enteritidis and E. coli are thermodynamically unfavorable for both surfaces studied (∆G(adhesion)>0). Despite these data, good adhesion occurred on both surfaces. The number of bacteria on green pepper slices was 7.3 and 7.0 log CFU/cm(2) for E. coli and S. enterica Enteritidis, respectively. For melon surfaces, the number of bacteria was 7.0 and 6.9 log CFU/cm(2) for E. coli and S. Enteritidis, respectively. The greater adherence of both bacteria on the green peppers can be explained by its hydrophobic surface; the hydrophilic surfaces of melons resulted in lower adherence. These results suggest that the adhesion observed in this experiment is a multifactorial process. Among the treatments evaluated for green peppers, a higher removal of pathogens was observed after use of a combination of ultrasound and 1% lactic acid; this treatment reduced E. coli and Salmonella by 2.9 and 2.8 log CFU/cm(2), respectively. For melons, the combination of ultrasound and lactic acid showed a reduction of 2.5 and 3.1 log CFU/cm(2) for E. coli and S. Enteritidis, respectively. These results indicate that it is possible to replace the chlorinated compounds that are commonly used to sanitize fruits and vegetables. These results confirm that ultrasound, an emerging technology for food processing applications, could enhance the microbial safety of fresh produce.

Concentração inibitória mínima de óleo essencial de gengibre frente a microrganismos patogênicos / Minimum inhibitory concentration of ginger oil essential against pathogenic microorganism

Óleos essenciais extraídos de condimentos representam uma alternativa para conservação de alimentos processados, em especial pela atividade antimicrobiana. No presente trabalho foi determinada a Concentração Mínima Inibitória (CMI) frente a B. cereus, E. coli, P. aeruginosa, S. Typhimurium e S. aureus, por microdiluição em caldo in vitro em microplacas de 96 poços. O maior potencial antimicrobiano do óleo foi evidenciado frente a S. aureus(CMI de 3,13%), seguido por E. coli (6,25%) e S. Typhimurium (12,5%). A comprovação da atividade antimicrobiana do óleo demonstra seu potencial de aplicação como ingrediente natural, evidenciado pelo seu efeito na inibição de microrganismos patogênicos frequentemente associados a doenças de origem alimentar.

Influência do ultrassom no crescimento de Salmonella typhimurium / Influence of ultrasound in Salmonella typhimurium growth

O ultrassom tem sido amplamente estudado na inativação de microrganismos e no processamento de alimentos. Entretanto, o efeito sobre o crescimento de bactérias ainda é pouco elucidado. O presente estudo avaliou o efeito de diferentes densidades energéticas de ultrassom (0; 0,11; 0,22 e 0,43 KJ/mL) no crescimento de Salmonella enterica serovar Typhimurium em caldo BHI. Altas densidades energéticas diminuíram (p < 0,05) a duração da fase lag e a densidade de células na fase estacionária. Entretanto, não houve diferença (p < 0,05) na velocidade de crescimento. Portanto, os resultados do presente estudo alertam para os riscos do ultrassom quando aplicado isoladamente. Assim, as aplicações desta tecnologia, isoladamente, em alimentos que suportam o crescimento de patógenos, como carne e produtos cárneos, devem ser minuciosamente avaliadas para cada tipo de produto.

Physical and chemical quality, biodiversity, and thermodynamic prediction of adhesion of bacterial isolates from a water purification system: a case study

ABSTRACT The objective of this study was to evaluate the quality of water purification system and identify the bacteria this system, predict bacterial adherence according to the hydrophobicity of these microorganisms and of the polypropylene distribution loop for purified water. The assessment of drinking water that supplies the purification system allowed good-quality physical, chemical, and microbiological specifications. The physicochemical specifications of the distributed purified water were approved, but the heterotrophic bacteria count was higher than allowed (>2 log CFU mL-1).The sanitation of the storage tank with chlorine decreased the number of bacteria adhered to the surface (4.34 cycles log). By sequencing of the 16SrDNA genes, six species of bacteria were identified. The contact angle was determined and polypropylene surface and all bacteria were considered to be hydrophilic, and adhesion was thermodynamically unfavorable. This case study showed the importance of monitoring the water quality in the purified water systems and the importance of sanitization with chemical agents. The count of heterotrophic bacteria on the polypropylene surface was consistent with the predicted thermodynamics results because the number of adhered cells reached approximate values of 5 log CFU cm-2.