Jane Martha Graton Mikcha

Effect of Zingiber officinale essential oil on Fusarium verticillioides and fumonisin production

The antifungal activity of ginger essential oil (GEO; Zingiber officinale Roscoe) was evaluated against Fusarium verticillioides (Saccardo) Nirenberg. The minimum inhibitory concentration (MIC) of GEO was determined by micro-broth dilution. The effects of GEO on fumonisin and ergosterol production were evaluated at concentrations of 500-5000 μg/mL in liquid medium with a 5mm diameter mycelial disc of F. verticillioides. Gas chromatography-mass spectrometry showed that the predominant components of GEO were α-zingiberene (23.9%) and citral (21.7%). GEO exhibited inhibitory activity, with a MIC of 2500 μg/mL, and 4000 and 5000 μg/mL reduced ergosterol biosynthesis by 57% and 100%, respectively. The inhibitory effect on fumonisin B1 (FB1) and fumonisin B2 (FB2) production was significant at GEO concentrations of 4000 and 2000 μg/mL, respectively. Thus, the inhibition of fungal biomass and fumonisin production was dependent on the concentration of GEO. These results suggest that GEO was able to control the growth of F. verticillioides and subsequent fumonisin production.

Enzyme immunoassay using Leishmania (Viannia) braziliensis antigens for laboratorial diagnosis of American cutaneous leishmaniasis

American cutaneous leishmaniasis (ACL) has a wide geographical distribution, including all the states of Brazil. Parasitological and immunological tests are the most commonly used methods for the laboratorial diagnosis of ACL. The objective of this study was to find a specific and sensitive antigen to the diagnosis of ACL. To this end, promastigotes of Leishmania (Viannia) braziliensis were submitted to gel-filtration chromatography (Sephadex G100) and to ionic-change chromatography (DEAE-Sepharose Fast-Flow), and the antigen reactivity was evaluated by enzyme immunoassay (EIA-IgG). The results showed that the peak II of fraction 8 distinguished ACL patient sera from those of healthy individuals and individuals with other diseases (P<0.0001), presenting 85.41% sensitivity and 91.22% specificity. False-positive results were found for sera from Chagas disease patients (16.67%) and healthy individuals (10.42%). False-positive results were not detected for sera from patients with toxoplasmosis or paracoccidioidomycosis. The fraction obtained shows good sensitivity and specificity for ACL diagnosis and opens up new possibilities for the use of serology in laboratorial diagnosis, seroepidemiological studies and in the follow up of ACL treatment.

Resistance profile to antimicrobials of Salmonella spp. isolated from human infections

O objetivo deste estudo foi analisar o perfil de resistencia a antimicrobianos, de Salmonella isoladas de 21 amostras provenientes de pacientes com sintomatologia de gastroenterite. Verificou-se que S. enteritidis foi o sorotipo com maior prevalencia. Estas cepas mostraram-se sensiveis a maioria dos antimicrobianos testados, no entanto, as cepas S. typhimurium e S. enterica subsp. enterica sorotipo 4,5,12:i:-, mostraram-se resistentes a varios antimicrobianos. Vigilância e um monitoramento eficiente, para diminuir a resistencia antimicrobiana em microrganismos que causam infeccoes veiculadas por alimentos, devem ser prioridade para a saude publica.

Antibacterial activity of papain and bromelain on Alicyclobacillus spp.

Alicyclobacillus spp. are spore forming bacteria that are often related to the deterioration of acidic products such as beverages and citrus juices. After the process of industrial pasteurization, the spore produced by the bacteria can germinate and the microorganism can grow, causing sensory abnormalities in the product. Alternative biopreservatives, such as the antimicrobial compounds, are of considerable importance to the food industry. Papain and bromelain are proteolytic enzymes derived frompapaya and pineapple, respectively. These enzymes are widely used in medicine and in the pharmaceutical and food industries, but while some studies have described their antibacterial action, no studies of the Alicyclobacillus spp. exist. The aimof this studywas to analyze the antibacterial effect of papain and bromelain on Alicyclobacillus spp. through 1) determining minimum inhibitory and bactericidal concentration (MIC and MBC); 2) determining the death time curve of the micro-organism in the presence and absence of enzymes; and 3) investigating the enzymatic mechanism on the microorganism. The antibacterial activity of enzymes in combination with nisin was also evaluated. The results showed that for the Alicyclobacillus acidoterrestris strain, the MIC of papain was 0.98 μg/mL and the MBC was 3.91 μg/mL, while theMIC of bromelain was 62.5 μg/mL and the MBCwas 250 μg/mL. The concentration of 4 ×MIC for both the enzymes was sufficient to eliminate 4 logs of the micro-organism after 24 h of incubation. Through the use of enzyme inhibitors specific for cysteine proteases, it was found that the antibacterial activity of papain and bromelain is not related to its proteolytic activity, butmay be related to other activities, such as amidse and esterase. The synergistic activity of the enzymes revealed a fractional inhibitory concentration (FIC) level of 0.16. Combination with nisin revealed an FIC of 0.25 for papain and 0.19 for bromelain, indicating synergism between both compounds. The application of enzymes in reconstituted orange juice contaminated with A. acidoterrestris was found to be effective, as after 48 h of incubation, at three different temperatures, the initial microbial population was eliminated. This study showed that the enzymes papain and bromelain have an antibacterial effect on A. acidoterrestris.

Shiga-Toxin Genes and Genetic Diversity of Escherichia coli Isolated from Pasteurized Cow Milk in Brazil

UNLABELLED This study evaluated the genetic similarity and prevalence of the stx1, stx2, eae, and ehxA genes in Escherichia coli isolated from pasteurized cow milk. Eighty-seven E. coli isolates from pasteurized cow milk from 22 dairies located in northwestern Paraná state, Brazil, were analyzed. Genetic similarity was evaluated using enterobacterial repetitive intergenic consensus sequence polymerase chain reaction (ERIC-PCR) and repetitive extragenic palindromic sequence PCR (REP-PCR). E. coli isolates were also analyzed by PCR to investigate the presence of the stx1, stx2, eae, and ehxA genes. ERIC-PCR and REP-PCR clustered 87 bacterial isolates in 76 and 81 genomic profiles, respectively. Both techniques revealed high genetic diversity among the E. coli isolates, confirming the possibility of their use in epidemiological studies. The stx1, stx2, eae, and ehxA virulence genes were not detected in E. coli isolates, indicating a low prevalence of Shiga toxin-producing E. coli in milk produced in the region studied. PRACTICAL APPLICATION Knowledge about the presence of diarrheagenic Escherichia coli in pasteurized milk is important developing and implementing control measures in milk and dairy production.

Cinnamaldehyde induces changes in the protein profile of Salmonella Typhimurium biofilm

The effect of cinnamaldehyde against biofilm cells of Salmonella Typhimurium ATCC 14028 was evaluated. We also assessed differential protein patterns that were expressed by biofilms compared with planktonic cells and protein expression by cinnamaldehyde-treated biofilms cells. This compound decreased biofilm biomass and metabolic activity of biofilms at both concentrations tested. Cinnamaldehyde treatment reduced the number of attached cells in polypropylene, reflected by colony count and scanning electron microscopy. The proteomic analysis of biofilms compared with planktonic cells indicated that several proteins were upregulated or downregulated, especially proteins that are involved in energy metabolism. Peroxiredoxin, ATP synthase alpha chain protein, conjugal transfer nickase/helicase TraI and elongation factor G were upregulated in untreated-biofilm cells, and their expression decreased as a function of cinnamaldehyde treatment. Cinnamaldehyde had antibiofilm activity, and several differentially expressed proteins identified provide potential and interesting targets to explore new control strategies for S. Typhimurium biofilms.

Yacare caiman (Caiman yacare) trim hamburger and sausage subjected to different smoking techniques

BACKGROUND Caiman, as well as having skin that, after tanning, produces leather of high added value, exceptional quality and good market value, also possesses a meat with a remarkably smooth taste and appearance. This study aimed to characterize hamburger and sausages made from Yacare caiman (Caiman yacare) meat trim. RESULTS Hot smoked products contained less moisture than the unsmoked products. Protein and ash were higher, respectively, for hot smoked hamburger and sausage. Lipids had greater presence in hot smoked sausage (9.72%), whereas in the burgers they were higher in the liquid smoked burgers (6.71%). The hot smoked products had lower water activity. Hot smoked products displayed less luminance, but the a* and b* chroma were higher in smoked hamburgers. Taste, texture and general acceptability were significant for the hamburger, whereas for the sausage there was a significant effect for texture, salt and purchase intent. CONCLUSION For all the products, the hot smoking resulted in the lowest acceptability.

Aproveitamento de peles de tilápia-do-nilo congeladas e salgadas para extração de gelatina em processo batelada

The objective was to characterize Nile tilapia skins, freeze- and dry salt dry-preserved to extract gelatins by batch processing. After filleting, the skins were separated from the meat and distributed into two lots: In one, skins were frozen for 7 days (-18 oC); and in the other, skins were salted for seven days (25 oC). The skins were rinsed, weighed and pretreated in H2SO4 a10N solution (pH 3.0), at a 1:6 (skin/water) ratio for 1 h at 24 oC. Gelatin was extracted in water bath at 50 oC for 1 h, and a sample was removed for molecular profiling; the rest was frozen at -18 oC. Physical-chemical analyses were carried out on the skins and liquid gelatins, the molecular profile was obtained from the gelatins, and the skins underwent microbiological analyses. Frozen and salted skins showed, respectively: 78.13% and 76.46% moisture, 18.16% and 19.59% crude protein, 2.26% and 1.90% ether extract, and 1.44% and 2.06% ash, respectively. For the liquid gelatins extracted from frozen and salted skins, moisture was 97.68% and 96.08%, crude protein was 3.18% and 4.12%, ether extract was 0.29% and 0.18%, and ash was 2.31% and 3.03%, respectively. Gel strength and viscosity values were higher for salted skins gelatin (200 g and 19.02 mPas) compared with freeze-preserved skins gelatin (12.7 g and 9.16 mPas). The molecular profile was lower in gelatin extracted from frozen skins, which indicates loss of β and γ-components, which indicates considerable collagen decay from that preservation method.Objetivou-se caracterizar peles de tilapia-do-nilo, conservadas por congelamento e salga a seco, visando a extracao de gelatina em processo batelada. Apos a filetagem, as peles foram descarnadas e distribuidas em dois lotes. Um dos lotes foi congelado a -18 oC por sete dias e o outro foi salgado e mantido a 25 oC por sete dias. As peles foram lavadas, pesadas e pre-tratadas em solucao de H2SO4 a10N (pH 3,0), na proporcao de 1:6 (pele:agua) por uma hora a 24 oC. Extraiu-se a gelatina em banho-maria a 50 oC por uma hora e retirou-se uma amostra para analise do perfil molecular. O restante foi congelado a -18 oC. Foram realizadas analises fisico-quimicas das peles e das gelatinas liquidas, do perfil molecular com as gelatinas e analises microbiologicas das peles. As peles congeladas e salgadas apresentaram, respectivamente, 78,13 e 76,46% de umidade; 18,16 e 19,59% de proteina bruta; 2,26 e 1,90% de extrato etereo e 1,44 e 2,06% de cinzas. Nas gelatinas liquidas extraidas das peles congeladas e salgadas, a umidade foi de 97,68 e 96,08%, o conteudo de proteina bruta de 3,18 e 4,12%, de extrato etereo 0,29 e 0,18% e de cinzas de 2,31 e 3,03%, respectivamente. Os valores da forca de gel e viscosidade foram maiores para a gelatina de peles salgadas (200 g e 19,02mPas) em comparacao a gelatina de peles conservadas pelo congelamento (12,7 g e 9,16mPas). O perfil molecular foi menor na gelatina extraida a partir de peles congeladas, portanto houve perda de β e γ-componentes, que indica grande degradacao do colageno decorrente do metodo de conservacao.

Hemagglutinating properties of Salmonella enterica serovar Enteritidis isolated from different sources

Twenty-five strains of Salmonella enterica serovar Enteritidis isolated from different sources were examined for hemagglutinating activity. Bacteria cultured in different media induced hemagglutination of human erythrocytes, but no reaction was observed with erythrocytes from other animal species. The hemagglutinating expression activity was better for cultures on CFA agar at 37oC than other conditions examined. The hemagglutination was inhibited by D-mannose, D-mannitol, melibiose, D-raffinose, L-rhamnose and sucrose. The absence of cell-surface appendages in electron microscope examinations suggested a nonfimbrial hemagglutinin. The data suggest that Salmonella Enteritidis produces nonfimbrial mannose-sensitive hemagglutinin, specific for human erythrocytes, which could be extracted in soluble form.

Photodynamic inactivation of foodborne bacteria by eosin Y

The aim of this study was evaluate the effect of photodynamic inactivation mediated by eosin Y in Salmonella enterica serotype Typhimurium ATCC 14028, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778.