Abstract Probiotics are live microorganisms that when ingested in adequate amounts help in the balance of the intestinal microbiota. Kefir is considered a probiotic beverage associated with the improvement of several pathologies. Fruit juices are considered an excellent culture medium for these microorganisms, presenting nutrients that favor microbial growth. This work aimed to prepare a probiotic drink from the fermentation of whole grape juice by microorganisms from the water kefir. Different amounts of kefir grains were tested (5, 10, 20, 30, 40, 50, and 60 g) in 500 mL of grape juice. The fermentation processes were developed under static conditions at room temperature for 24 h. Seven formulations were tested for physical-chemical and microbiological analyses. A questionnaire on the knowledge and consumption of probiotics was applied to the academic community. Three formulations were selected for sensory analysis and stored under refrigeration. All formulations showed growth of lactic acid bacteria and no reduction in storage viability. A significant reduction in soluble solids was observed in all formulations, and an increase in acidity and pH formulations with 5 and 20 g of kefir, respectively. About 64% of the participants reported knowing the definition of probiotics. In addition, a low intake of this product was observed. The formulation with 5 grams of water kefir grains was better accepted by the consumers when compared to the others. Thus, grape juice can be a great alternative to consume probiotic microorganisms, especially for those who do not consume dairy products.

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.

A produção de cenoura em grande escala na região de Rio Paranaíba coloca essa região em posição de destaque no cenário nacional. No entanto, é relatado que ocorre significativa quantidade de sobras após a colheita. O aproveitamento do material descartado na cadeia de alimentos pode se concretizar pelo processamento mínimo, como uma alternativa de agregação de valor. A etapa de sanitização é de extrema importância durante a produção de vegetais minimamente processados. Nesse contexto, objetivou-se estudar o efeito antimicrobiano de nanopartículas de prata na sanitização de cenoura minimamente processada, obtida a partir do aproveitamento das sobras de cenouras da colheita da cidade de Rio Paranaíba, bem como o estudo da termodinâmica de adesão de diferentes estirpes bacterianas na superfície da cenoura sanitizada. Observou-se que as nanopartículas de prata (6mg L-1)apresentaram bons resultados, quando comparadas aos sanitizantes hipoclorito de sódio (100mg L-1) e dicloroisocianurato de sódio (150mg L-1), na descontaminação da cenoura minimamente processada sobre microrganismos mesófilos aeróbios; Pseudomonasspp.; bactérias láticas; e coliformes a 35ºC. Verificou-se também que a superfície da cenoura apresenta características hidrofílicas que podem dificultar a adesão bacteriana. Esse fato foi confirmado na avaliação de termodinâmica de adesão, que foi desfavorável paraStaphylococcus aureus, Escherichia colie Listeria innocua, sendo mais desfavorável para as interações envolvendo as superfícies de cenoura sanitizadas com nanopartículas de prata.

The carrot production on a large scale in the region of Rio Paranaiba places the region in a prominent position on the national scene. However, it is reported that a significant amount of scraps occurs after harvest. The use of discarded material in the food chain can be realized by minimal processing, as an alternative of adding value. A sanitization step is very important during the production of minimally processed vegetables. In this context, this research aimed to study the antimicrobial effect of silver nanoparticles in the sanitization of minimal processing carrot from discarded carrot harvested at Rio Paranaiba city, as well as study the thermodynamics adhesion for different bacterial strains in sanitized carrot surface. It was observed that silver nanoparticles (6mg L-1) showed good results when was compared to sodium hypochlorite (100mg L-1) and sodium dichloroisocyanurate (150mg L-1) in reducing populations of aerobic mesophilic microorganism;Pseudomonasspp. lactic acid bacteria and coliforms at 35ºC present in carrot. It was also found that the surface of carrot has hydrophilic characteristics which can prevent bacterial adhesion. This fact was confirmed that thermodynamic evaluation of adhesion that was unfavorable for Staphylococcus aureus, Escherichia coliand Listeria innocua, and more thermodynamically unfavorable for interactions involving carrot surfaces sanitized with silver nanoparticles.

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. Inaddition 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 pre-conditioning 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.

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.

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.

A adesão de Pseudomonas fluorescens foi avaliada em nove tipos de superfícies de processamento de alimentos por contagem padrão em placas. Superfícies de mármore, granito, aço inoxidável, poli(cloreto de vinila), poliuretano e silicone revestidos com tecido foram avaliadas. O número de células aderidas aumentou com o tempo de contato, alcançando 5,0-6,1 log UFC.cm-2 após 10 horas, o qual pode ser considerado um processo de adesão bem estabelecido. O número de células aderidas duplicou em 29,5 minutos em aço inoxidável e 23,5 minutos em poli(cloreto de vinila) revestido com tecido. Nas outras superfícies, em média, esse valor foi 9,8 minutos p > 0,05) no grau de adesão de células após 2 e 10 horas. As superfícies avaliadas com elevadas porcentagens de similaridade no nível de adesão e contagens de células aderidas foram poliuretano rugoso dupla face, silicone revestido com tecido e granito. As superfícies apresentaram características de microtopografias diferentes quando observadas por microscopia eletrônica de varredura. O experimento mostrou a importância da escolha adequada de materiais para contato com alimentos durante o processamento, os quais irão afetar os procedimentos de limpeza e sanitização.

The adherence of Pseudomonas fluorescens cells to nine food-processing contact surfaces was evaluated using the plate-count method. The surfaces include marble, granite, stainless steel, polyvinyl chloride, polyurethane, and silicone-coated cloth, which have been used only in a few studies concerning bacterial adherence. The number of cells adhered to the surfaces increased with contact time reaching 5.0-6.1 log CDM.cm-2 after 10 hours, which can be considered a well established adherence process. The number of adhered cells doubled in 29.5 minutes and 23.5 minutes on stainless steel and thin polyvinyl chloride-coated cloth, respectively. For the other surfaces, this value was 9.8 minutes on average. Marble, granite, thick polyvinyl-coated cloth, double-faced rugous polyurethane, and silicone-coated cloth were not different (p < 0.05) in their ability to adhere cells (CFU/cm²) after 2 and 10 hours. The surfaces that had higher percentage of similarity in the adhesion level and higher log CFU/cm² of adhered cells were double-faced rugous polyurethane, silicone-coated cloth, and granite. The surfaces showed very different microtopography characteristics when viewed using scanning electron microscopy. This experiment showed the importance of using appropriate materials for food contact during processing, which will affect the cleaning and sanitation procedures.