Encapsulação de antimicrobianos naturais em nanolipossomas para inibição de bactérias causadoras de surtos alimentares / Encapsulation of natural antimicrobials in nanoliposomas for the inhibition of bacterials causing foodborne disease

Avaliou-se ação bactericida e caracterização físico-química de duas diferentes formulações de nanolipossomas preparados utilizando técnica de hidratação do filme lipídico. Nanolipossomas contendo carvacrol apresentaram diâmetro médio de 270,83 nm, PDI de 0,20 e potencial zeta de + 8,64 mV. Nanolipossomas contendo carvacrol e nisina apresentaram diâmetro médio de 205,25 nm, PDI de 0,31 e potencial zeta de - 22,48 mV. Para ambas formulações a concentração bactericida mínima foi de 3,53 mg/mL para Salmonella e 5,3 mg/mL para Escherichia coli e Staphylococcus aureus. Não ocorreu efeito sinérgico entre carvacrol e nisina, porém os nanolipossomas contendo carvacrol apresentaram ação bactericida contra os microrganismos testados, demonstrando potencial para sua utilização no desenvolvimento de um sanitizante para uso em indústrias de alimentos.(AU)

Desenvolvimento e caracterização de nanocápsulas poliméricas contendo carvacrol para inibição de Salmonella enteritidis / Development and characterization of polymeric nanocapsules containing carvacrol for inhibition from Salmonella enteritidis

Avaliou-se caracterização físico-química, ação bactericida e estabilidade de nanocápsulas poliméricas de Eudragit contendo carvacrol preparadas utilizando técnica de deposição interfacial do polímero pré-formado. As nanocápsulas apresentaram diâmetro médio de 146 nm, PDI de 0,181 e potencial zeta de + 23,44 mV e a concentração bactericida mínima necessária para inativar Salmonella Enteritidis foi de 0,331 mg/mL. A solução contendo nanocápsulas manteve suas características físico-químicas e atividade bactericida inalteradas durante os 45 dias do teste de estabilidade, demonstrando características promissoras para o desenvolvimento de um sanitizantes para uso em indústria produtora de ovos e frigorífico de aves.(AU)

Desenvolvimento e caracterização de nanocápsulas poliméricas contendo carvacrol para inibição de Salmonella enteritidis / Development and characterization of polymeric nanocapsules containing carvacrol for inhibition from Salmonella enteritidis

Avaliou-se caracterização físico-química, ação bactericida e estabilidade de nanocápsulas poliméricas de Eudragit contendo carvacrol preparadas utilizando técnica de deposição interfacial do polímero pré-formado. As nanocápsulas apresentaram diâmetro médio de 146 nm, PDI de 0,181 e potencial zeta de + 23,44 mV e a concentração bactericida mínima necessária para inativar Salmonella Enteritidis foi de 0,331 mg/mL. A solução contendo nanocápsulas manteve suas características físico-químicas e atividade bactericida inalteradas durante os 45 dias do teste de estabilidade, demonstrando características promissoras para o desenvolvimento de um sanitizantes para uso em indústria produtora de ovos e frigorífico de aves.

Encapsulação de antimicrobianos naturais em nanolipossomas para inibição de bactérias causadoras de surtos alimentares / Encapsulation of natural antimicrobials in nanoliposomas for the inhibition of bacterials causing foodborne disease

Avaliou-se ação bactericida e caracterização físico-química de duas diferentes formulações de nanolipossomas preparados utilizando técnica de hidratação do filme lipídico. Nanolipossomas contendo carvacrol apresentaram diâmetro médio de 270,83 nm, PDI de 0,20 e potencial zeta de + 8,64 mV. Nanolipossomas contendo carvacrol e nisina apresentaram diâmetro médio de 205,25 nm, PDI de 0,31 e potencial zeta de - 22,48 mV. Para ambas formulações a concentração bactericida mínima foi de 3,53 mg/mL para Salmonella e 5,3 mg/mL para Escherichia coli e Staphylococcus aureus. Não ocorreu efeito sinérgico entre carvacrol e nisina, porém os nanolipossomas contendo carvacrol apresentaram ação bactericida contra os microrganismos testados, demonstrando potencial para sua utilização no desenvolvimento de um sanitizante para uso em indústrias de alimentos.

Commonly screened antibiotics in raw milk from dairy plants under State Inspection in Rio Grande do Sul, Brazil / Antibióticos comumente investigados no leite cru em laticínios sujeitos a Inspeção Estadual no Rio Grande do Sul, Brasil

This study aimed at identifying the commonly screened antibiotics during the dairy processing routine in raw-milk receiving points in plants inspected by the official services in the state of Rio Grande do Sul (RS), from January 2014 to February 2015. Among the 36 participating industries, the most commonly screened antibiotics were beta lactams (100%) and tetracyclines (69%). The antibiotics screened at the milk receiving point were chosen because of the practicality and speed in performing the screening (67%), rather than specific knowledge on which antibiotics the milk suppliers used. (22%).(AU)

Este estudo teve por objetivo identificar os antibióticos comumente investigados durante a rotina de processamento do leite cru recebido em laticínios sob Inspeção Estadual no Rio Grande do Sul (RS), entre janeiro de 2014 e fevereiro de 2015. Entre as 36 indústrias participantes, os antibióticos mais comumente investigados foram beta-lactâmicos (100%) e tetraciclinas (69%). A seleção por quais antibióticos investigar no recebimento do leite foi influenciada pela praticidade e rapidez na execução da análise (67%), em detrimento do conhecimento específico sobre quais antibióticos eram utilizados pelos produtores de leite (22%).(AU)

Commonly screened antibiotics in raw milk from dairy plants under State Inspection in Rio Grande do Sul, Brazil / Antibióticos comumente investigados no leite cru em laticínios sujeitos a Inspeção Estadual no Rio Grande do Sul, Brasil

This study aimed at identifying the commonly screened antibiotics during the dairy processing routine in raw-milk receiving points in plants inspected by the official services in the state of Rio Grande do Sul (RS), from January 2014 to February 2015. Among the 36 participating industries, the most commonly screened antibiotics were beta lactams (100%) and tetracyclines (69%). The antibiotics screened at the milk receiving point were chosen because of the practicality and speed in performing the screening (67%), rather than specific knowledge on which antibiotics the milk suppliers used. (22%).(AU)

Este estudo teve por objetivo identificar os antibióticos comumente investigados durante a rotina de processamento do leite cru recebido em laticínios sob Inspeção Estadual no Rio Grande do Sul (RS), entre janeiro de 2014 e fevereiro de 2015. Entre as 36 indústrias participantes, os antibióticos mais comumente investigados foram beta-lactâmicos (100%) e tetraciclinas (69%). A seleção por quais antibióticos investigar no recebimento do leite foi influenciada pela praticidade e rapidez na execução da análise (67%), em detrimento do conhecimento específico sobre quais antibióticos eram utilizados pelos produtores de leite (22%).(AU)

Activity of the antimicrobial peptide P34 against bovine alphaherpesvirus type 1 / Atividade do peptídeo antimicrobiano P34 contra o alfaherpesvírus bovino tipo 1

Previous studies have demonstrated the antimicrobial activity of the peptide P34. In this study, the antiviral potential of P34 and the in vitro mechanism of action were investigated against bovine alphaherpesvirus type 1 (BoHV1). P34 exhibited low toxicity, a high selectivity index (22.9) and a percentage of inhibition of up to 100% in MDBK cells. Results from antiviral assays indicated that P34 did not interact with cell receptors, but it was able to inhibit the viral penetration immediately after pre-adsorption. In addition, BoHV1 growth curve in MDBK cells in the presence of P34 revealed a significant reduction in virus titer only 8h post-infection, also suggesting an important role at late stages of the replicative cycle. Virucidal effect was observed only in cytotoxic concentrations of the peptide. These findings showed that the antimicrobial peptide P34 may be considered as a potential novel inhibitor of in vitro herpesviruses and must encourage further investigation of its antiherpetic activity in animal models as well as against a wide spectrum of viruses.

A atividade antimicrobiana do peptídeo P34 já foi previamente demonstrada. Neste estudo, o potencial antiviral do P34 e o mecanismo de ação in vitro contra o alfaherpesvírus bovino tipo 1 (BoHV1) foram investigados. O P34 exibiu baixa toxicidade, alto índice de seletividade (22.9) e percentagem de inibição viral de até 100% em células MDBK. Os resultados dos ensaios antivirais indicaram que não interage com receptores celulares, mas é capaz de inibir a penetração viral, imediatamente após a pré-adsorção. Além disso, a curva de crescimento do BoHV1 em células MDBK na presença do P34 revelou uma significativa redução no título somente após 8h de infecção, sugerindo também uma importante atividade do peptídeo nas fases finais do ciclo replicativo. Efeito virucida frente / BoHV1 foi observado apenas em concentrações citotóxicas do peptídeo. Os dados obtidos indicam que o peptídeo antimicrobiano P34 pode ser considerado um potencial composto inibidor de herpesvírus, in vitro, e estimulam posteriores investigações sobre sua atividade anti-herpética em modelos animais, bem como contra outros vírus.

Activity of the antimicrobial peptide P34 against bovine alphaherpesvirus type 1 / Atividade do peptídeo antimicrobiano P34 contra o alfaherpesvírus bovino tipo 1

Previous studies have demonstrated the antimicrobial activity of the peptide P34. In this study, the antiviral potential of P34 and the in vitro mechanism of action were investigated against bovine alphaherpesvirus type 1 (BoHV1). P34 exhibited low toxicity, a high selectivity index (22.9) and a percentage of inhibition of up to 100% in MDBK cells. Results from antiviral assays indicated that P34 did not interact with cell receptors, but it was able to inhibit the viral penetration immediately after pre-adsorption. In addition, BoHV1 growth curve in MDBK cells in the presence of P34 revealed a significant reduction in virus titer only 8h post-infection, also suggesting an important role at late stages of the replicative cycle. Virucidal effect was observed only in cytotoxic concentrations of the peptide. These findings showed that the antimicrobial peptide P34 may be considered as a potential novel inhibitor of in vitro herpesviruses and must encourage further investigation of its antiherpetic activity in animal models as well as against a wide spectrum of viruses.(AU)

A atividade antimicrobiana do peptídeo P34 já foi previamente demonstrada. Neste estudo, o potencial antiviral do P34 e o mecanismo de ação in vitro contra o alfaherpesvírus bovino tipo 1 (BoHV1) foram investigados. O P34 exibiu baixa toxicidade, alto índice de seletividade (22.9) e percentagem de inibição viral de até 100% em células MDBK. Os resultados dos ensaios antivirais indicaram que não interage com receptores celulares, mas é capaz de inibir a penetração viral, imediatamente após a pré-adsorção. Além disso, a curva de crescimento do BoHV1 em células MDBK na presença do P34 revelou uma significativa redução no título somente após 8h de infecção, sugerindo também uma importante atividade do peptídeo nas fases finais do ciclo replicativo. Efeito virucida frente / BoHV1 foi observado apenas em concentrações citotóxicas do peptídeo. Os dados obtidos indicam que o peptídeo antimicrobiano P34 pode ser considerado um potencial composto inibidor de herpesvírus, in vitro, e estimulam posteriores investigações sobre sua atividade anti-herpética em modelos animais, bem como contra outros vírus.(AU)

Antiviral activity of a Bacillus sp: P34 peptide against pathogenic viruses of domestic animals

P34 is an antimicrobial peptide produced by a Bacillus sp. strain isolated from the intestinal contents of a fish in the Brazilian Amazon basin with reported antibacterial activity. The aim of this work was to evaluate the peptide P34 for its in vitro antiviral properties against canine adenovirus type 2 (CAV-2), canine coronavirus (CCoV), canine distemper virus (CDV), canine parvovirus type 2 (CPV-2), equine arteritis virus (EAV), equine influenza virus (EIV), feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1). The results showed that the peptide P34 exhibited antiviral activity against EAV and FHV-1. The peptide P34 inhibited the replication of EAV by 99.9% and FHV-1 by 94.4%. Virucidal activity was detected only against EAV. When P34 and EAV were incubated for 6 h at 37 °C the viral titer reduced from 10(4.5) TCID50 to 10(2.75) TCID50, showing a percent of inhibition of 98.6%. In conclusion, our results demonstrated that P34 inhibited EAV and FHV-1 replication in infected cell cultures and it showed virucidal activity against EAV. Since there is documented resistance to the current drugs used against herpesviruses and there is no treatment for equine viral arteritis, it is advisable to search for new antiviral compounds to overcome these infections.

Antibacterial activity of bacteriocin-like substance P34 on Listeria monocytogenes in chicken sausage

The antimicrobial activity of the bacteriocin-like substance (BLS) P34 against Listeria monocytogenes was investigated in chicken sausage. The BLS was applied to chicken sausages (256 AU g-1) previously inoculated with a suspension of 10² cfu g-1 of L. monocytogenes. BLS P34 inhibited the indicator microorganism in situ in all incubation times for up to 10 days at 5 °C. The effectiveness of BLS P34 was increased when it was added in combination with nisin. The bacteriocin was also tested in natural eatable natural bovine wrapping (salty semi-dried tripe) against the same indicator microorganism, also showing inhibitory capability in vitro. BLS P34 showed potential to control L. monocytogenes in refrigerated meat products.

Antibacterial activity of bacteriocin-like substance P34 on Listeria monocytogenes in chicken sausage

The antimicrobial activity of the bacteriocin-like substance (BLS) P34 against Listeria monocytogenes was investigated in chicken sausage. The BLS was applied to chicken sausages (256 AU g-1) previously inoculated with a suspension of 10² cfu g-1 of L. monocytogenes. BLS P34 inhibited the indicator microorganism in situ in all incubation times for up to 10 days at 5 °C. The effectiveness of BLS P34 was increased when it was added in combination with nisin. The bacteriocin was also tested in natural eatable natural bovine wrapping (salty semi-dried tripe) against the same indicator microorganism, also showing inhibitory capability in vitro. BLS P34 showed potential to control L. monocytogenes in refrigerated meat products.

Inhibition of listeria monocytogenes in minas frescal cheese by free and nanovesicle-encapsulated nisin

The effectiveness of free and nanovesicle-encapsulated nisin to control Listeria monocytogenes in Minas Frescal cheese was investigated. Commercial nisin was encapsulated into liposomes of partially purified soy lecithin. Free (0.1 mg/mL and 0.25 mg/mL) and nanovesicle-encapsulated nisin (0.25 mg/mL) were applied onto the surface of cheese samples, and L. monocytogenes was inoculated before incubation at 6-8°C for 28 days. A bactericidal effect was observed with 0.25 mg/mL free nisin; a bacteriostatic effect was observed for liposome-encapsulated nisin and 0.1 mg/mL free nisin. Free nisin was more efficient than nisin-loaded liposomes in controlling L. monocytogenes. Possible reasons for this behavior, and also the significance of nisin to soft cheeses are discussed. Nisin acted as a suitable barrier within hurdle technology, potentially extending the shelf-life and safety of fresh cheeses.(AU)

Isolation of Haemophilus parasuis from Diagnostic Samples in the South of Brazil

Haemophilus parasuis is one of the first and most prevalent colonizers of piglets, affecting the swine population from 2 weeks to 4 months of age. In this work, the relative incidence of H. parasuis isolated from swine in the west of Santa Catarina from 2007 to 2010 was investigated. White, flat and non-hemolytic colonies (satellitism growth with Staphylococcus aureus) of approximately 1 mm in length were identified by biochemical tests. Out of 384 samples examined during this period, 32 (8.33%) tested positive to isolation of H. parasuis. In 2007 and 2008 only 1 case of H. parasuis was isolated per year from a total of 62 and 60 samples, respectively. In 2009, 19 cases from 126 (15.08%) and in 2010, 11 cases of H. parasuis were isolated from a total of 136 samples (8.09%). These results suggest a growing incidence of this bacterium in the swine flock in this area.(AU)

Hydrolytic potential of a psychrotrophic Pseudomonas isolated from refrigerated raw milk

The production of extracellular hydrolases by a psychrotrophic bacterium isolated from refrigerated raw milk, and identified as a Pseudomonas sp. belonging to the Pseudomonas jenssenii group, was studied. This bacterium produced proteolytic and lipolytic enzymes in all media investigated (skim milk, cheese whey, casein broth, and tryptone soy broth). High levels of -glucosidase were produced in skim milk broth. Hydrolytic enzymes detected in skim milk broth are of particular concern, indicating that these enzymes could be produced by Pseudomonas sp. during the cold storage of raw milk, contributing to the spoilage problem in milk and dairy products.

Production of bacteriocin-like substances by lactic acid bacteria isolated from regional ovine cheese

Lactic acid bacteria (LAB) were isolated from ovine milk and cheeses manufactured in the South Region of Brazil. Among 112 bacterial isolates investigated, 59 were chosen through a screening for LAB. Among these 59 strains of LAB, 21% showed antimicrobial, proteolytic and lipolytic activities. Based on this screening, Lactobacillus plantarum LCN 17 and Lactobacillus rhamnosus LCN 43 were selected and tested for the production of bacteriocin-like substances (BLS). The BLS produced by both isolates showed antimicrobial activity against Listeria monocytogenes, whereas that produced by L. plantarum LCN 17 presented higher stability to different temperature, pH and enzyme treatments. These strains present potential for production of BLS, and for use as starter cultures.

Detection of Paenibacillus larvae by Real-Time PCR

Background: Paenibacillus larvae is the agent of the American Foulbrood disease (AFB), which may determine the death of the hive. The detection strategy for its diagnosis is based on clinical signs of disease, isolation and identification of P. larvae, which usually employs microbiological and biochemical methods. Recently, molecular methods based on analysis of 16S rDNA by conventional PCR have been adopted, providing greater security and analytical speed. The rapid diagnosis is important to minimize economic losses and assess routes of spread of the pathogen. Despite the strong existing sanitary control, P. larvae was recently identified in the Brazilian states of Rio Grande do Sul and Paraná. After that, outbreaks have been reported in neighboring countries. This investigation was conducted to develop a protocol for detection of P. larvae by real-time PCR, allowing the reduction in the time of diagnosis, without loss of robustness found in the conventional PCR methods. Materials, Methods & Results: Twenty-nine (29) P. larvae strains were evaluated by real-time PCR using SYBR Green. The primers Pltr-F/R were designed according to the sequence X60619 of 16S rDNA gene published in GenBank, to amplify a fragment of 74 base pairs. The target gene is highly conserved and specific to P. larvae. The amplification conditions consisted of 1 cycle of 50°C for 2 min and 1 cycle of 95°C for 10 min, followed by 40 cycles of 95°C for 15 s and 60°C for 1 min. The fluorescence was monitored during the annealing at 60°C. The reactions were conducted in a 7500 Real Time PCR System equipment, using SYBRGreen PCR master mix (both Applied Biosystems), containing 2X Platinum SYBRGreen qPCR Supermix-UDG. The concentrations of primers were 1, 10 and 100 mM, and different concentrations of MgCl2 (0,0 mM de MgCl2, 1.0 mM de MgCl2, 2.0 mM de MgCl2 and 3.0 mM de MgCl2) were tested, with a final volume of 50 mL; 25 mL and 15 mL, containing a 5 mL sample.(...)

Detection of Paenibacillus larvae by Real-Time PCR

Background: Paenibacillus larvae is the agent of the American Foulbrood disease (AFB), which may determine the death of the hive. The detection strategy for its diagnosis is based on clinical signs of disease, isolation and identification of P. larvae, which usually employs microbiological and biochemical methods. Recently, molecular methods based on analysis of 16S rDNA by conventional PCR have been adopted, providing greater security and analytical speed. The rapid diagnosis is important to minimize economic losses and assess routes of spread of the pathogen. Despite the strong existing sanitary control, P. larvae was recently identified in the Brazilian states of Rio Grande do Sul and Paraná. After that, outbreaks have been reported in neighboring countries. This investigation was conducted to develop a protocol for detection of P. larvae by real-time PCR, allowing the reduction in the time of diagnosis, without loss of robustness found in the conventional PCR methods. Materials, Methods & Results: Twenty-nine (29) P. larvae strains were evaluated by real-time PCR using SYBR Green. The primers Pltr-F/R were designed according to the sequence X60619 of 16S rDNA gene published in GenBank, to amplify a fragment of 74 base pairs. The target gene is highly conserved and specific to P. larvae. The amplification conditions consisted of 1 cycle of 50°C for 2 min and 1 cycle of 95°C for 10 min, followed by 40 cycles of 95°C for 15 s and 60°C for 1 min. The fluorescence was monitored during the annealing at 60°C. The reactions were conducted in a 7500 Real Time PCR System equipment, using SYBRGreen PCR master mix (both Applied Biosystems), containing 2X Platinum SYBRGreen qPCR Supermix-UDG. The concentrations of primers were 1, 10 and 100 mM, and different concentrations of MgCl2 (0,0 mM de MgCl2, 1.0 mM de MgCl2, 2.0 mM de MgCl2 and 3.0 mM de MgCl2) were tested, with a final volume of 50 mL; 25 mL and 15 mL, containing a 5 mL sample.(...)(AU)

Avaliação da resistência de Salmonella à ação de desinfetantes ácido peracético, quaternário de amônio e hipoclorito de sódio / The resistance of Salmonella strains to the biocides peracetic acid, quaternary ammonium and sodium hypochlorite

Este estudo avaliou a resistência de três cepas de Salmonella frente aos desinfetantes ácido peracético, quaternário de amônio e hipoclorito de sódio. S. Enteritidis (SE86), responsável por mais de 90% dos surtos alimentares ocorridos no Rio Grande do Sul (RS), foi comparada com S. Typhimurium e S. Bredeney, ambas não envolvidas na ocorrência de salmonelose. A resistência aos desinfetantes foi avaliada por meio de teste de suspensão, conforme preconizado pelo Ministério da Agricultura, Pecuária e Abastecimento. Todos os desinfetantes avaliados, nas concentrações indicadas pelos fabricantes, foram capazes de inativar as três cepas de Salmonella, entretanto, SE86 apresentou maior resistência ao hipoclorito de sódio a 400 ppm, além de ser a única cepa bacteriana capaz de sobreviver por até 15 minutos de exposição a 200 ppm desse desinfetante. Uma vez que o hipoclorito de sódio, nestas condições, é empregado com frequência como agente de desinfecção em indústrias de alimentos e serviços de alimentação, as características acima mencionadas podem contribuir para que esse microrganismo seja responsável pelos surtos de salmoneloses ocorridos no RS. Em função da importância desses micro-organismos como agentes patogênicos alimentares, cuidados especiais devem ser tomados nos processos de desinfecção e contaminação cruzada por Salmonella. (AU)

The resistance of Salmonella strains to the biocides peracetic acid, quaternary ammonium and sodiumhypochlorite was assessed. S. Enteritidis (SE86), which is responsible for more than 90% of food-borneoutbreaks occurred in Rio Grande do Sul (RS) was compared to S. Typhimurium and S. Bredeney, bothnot related to salmonellosis. The bacterial resistance to biocides was evaluated using the suspension test asrecommended by The Brazilian Agriculture Ministry. The three biocides were able to inactivate all of themicroorganisms tested, when the concentrations indicated by the manufacturers were used. However, SE86was resistant to 400 ppm sodium hypochlorite, and survived for up to 15 minutes of exposure to 200 ppmof this biocide, which was not demonstrated by the other bacteria strains. Since the sodium hypochlorite,at such concentration and time of exposure, is frequently used at food industries and food services, andowing to the above cited resistance characteristic, this condition could be contributing for the SE86 withfood-borne salmonellosis outbreak occurred in RS. In view of the importance of these microorganismsas alimentary pathogens, special cares in the food disinfection processes and cross-contamination withSalmonella must be taken.(AU)

Adhesion and biocides inactivation of Salmonella on stainless steel and polyethylene

The adhesion of Salmonella (S.) strains to stainless steel and polyethylene and their inactivation by biocides used in food industry was investigated. Coupons of stainless steel and polyethylene were immersed in bacterial suspensions of S. Enteritidis, S. Typhimurium, and S. Bredeney during 15, 30, and 60 minutes, and submitted to different concentrations of peracetic acid (PAA), sodium hypochlorite (NaOCl), and quaternary ammonium (Quat) sanitizers. Hydrophobicity of the surfaces was evaluated by contact angle measurements using the sessile drop method and bacterial adhesion was accompanied through bacterial counts and scanning electron microscopy (SEM). Results indicated that the three serovars of Salmonella presented similar adhesion to both materials (5.0 to 6.5 log cfu cm-2). The time of exposure did not influence the counts of adhered cells on both surfaces, however SEM revealed larger clusters of S. Enteritidis on both materials, not found for the other serovars. S. Enteritidis presented lower sessile drop angle on polyethylene, indicating hydrophilic properties of this material. The biocides were not able to inactivate all the microorganisms adhered on both surfaces. At least 1 log cfu cm-2 of all serovars tested remained viable after the exposure to different biocide concentrations. In general, higher counts of survivors were observed on polyethylene disinfected with different concentrations of biocides. S. Bredeney e S. Typhimurium were more resistant than S. Enteritidis to PAA, whilst S. Enteritidis presented smaller reduction rates to NaOCl. This last biocide was able to reduce Salmonella counts in approximately 3.0 to 4.0 log cm-2. When adhered to polyethylene, the serovars S. Typhimurium and S. Enteritidis were more resistant to Quat than S. Bredeney in all concentrations tested, and the numbers of S. Enteritidis remained almost unaltered. On stainless steel disinfected by Quat, S. Bredeney presented higher numbers of survivors.

Parâmetros microbiológicos e físico-químicos durante a produção e maturação do queijo Fascal

A produção de produtos lácteos de ovelha pode proporcionar uma alternativa rentável em relação aos produtos de leite bovino, devido ao sabor e à textura específicos. Leites ovino e caprino podem ser utilizados em diferentes aplicações e têm-se tornado um meio muito importante para a economia em distintas regiões geográficas. O objetivo deste trabalho foi avaliar a qualidade do leite de ovelha e do queijo Fascal produzido na região metropolitana de Porto Alegre, RS. As amostras de queijo foram analisadas no 1, 30, 60 e 90 dias de maturação, para verificar possíveis alterações nos parâmetros microbiológicos e físico-químicos. Estas amostras foram mantidas em câmara refrigerada durante o período de maturação. Os resultados indicaram ausência de Salmonella spp. em todas as amostras analisadas. As contagens de aeróbios mesófilos, estafilococos coagulase positiva, coliformes totais e coliformes fecais demonstraram resultados considerados aceitáveis, de acordo com a legislação brasileira para leite cru e para produtos lácteos. Os parâmetros físico-químicos do leite ovino apresentaram valores semelhantes aos encontrados em amostras de leite de ovelha provenientes do sul do Brasil. Em função dos resultados, concluiu-se que as características físico-químicas do queijo foram modificadas durante a maturação, com diminuição no conteúdo de umidade e aumento nos teores de proteína e gord