Staphylococcus aureus Isolated From Traditional Artisanal Raw Milk Cheese from Southern Brazil: Diversity, Virulence, and Antimicrobial Resistance Profile.

Staphylococcus aureus is one of the primary pathogenic agents found in cheeses produced with raw milk. Some strains of S. aureus are enterotoxigenic, possessing the ability to produce toxins responsible for staphylococcal food poisoning when present in contaminated foods. This study aimed to genotypically characterize, assess the antimicrobial resistance profile, and examine the enterotoxigenic potential of strains of S. aureus isolated from artisanal colonial cheese. Additionally, a bacterial diversity assessment in the cheeses was conducted by sequencing the 16S rRNA gene. The metataxomic profile revealed the presence of 68 distinct species in the cheese samples. Fifty-seven isolates of S. aureus were identified, with highlighted resistance to penicillin in 33% of the isolates, followed by clindamycin (28%), erythromycin (26%), and tetracycline (23%). The evaluated strains also exhibited inducible resistance to clindamycin, with nine isolates considered multidrug-resistant (MDR). The agr type I was the most prevalent (62%) among the isolates, followed by agr type II (24%). Additionally, ten spa types were identified. Although no enterotoxins and their associated genes were detected in the samples and isolates, respectively, the Panton-Valentine leukocidin gene (lukS-lukF) was found in 39% of the isolates. The presence of MDR pathogens in the artisanal raw milk cheese production chain underscores the need for quality management to prevent the contamination and dissemination of S. aureus strains.

Norovirus and rotavirus in surface, malacoculture, and human consumption water in Santa Catarina State, Brazil.

This study evaluated the results recorded at the Central Public Health Laboratory of Santa Catarina state (Brazil) concerning the investigation of Rotavirus (RVA) and Norovirus (NoVs) - genogroups GI and GII. Samples were taken from seawater, river water, estuary water, lagoon water, and treated water samples, from 2018 to 2021. The aim was to correlate them with each other and evaluate their association with the type of water, presence of shellfish farming, population density, and sewage treatment. The most prevalent enteric virus was RVA, followed by NoV GI and NoV GII. There was a strong correlation between the presence/absence of RVA and the presence/absence of at least one NoV genogroup, mainly in samples collected in rivers. No correlation was observed between the presence of any virus and the presence of shellfish farming. When evaluating the binomial sewage treatment vs. population density, the correlation coefficients between population density and the presence of the virus in a sample were higher than the coefficients between the percentage of treated sewage and the presence of the virus. Sources of human-origin pollution impair the quality of treated and surface waters, and therefore the results of this work can help develop viral-monitoring programs in these places.

Bioaccumulation Dynamic by Crassostrea gigas Oysters of Viruses That Are Proposed as Surrogates for Enteric Virus Contamination in Environmental Samples.

Oysters are filter-feeders and retain sewage-derived pathogens in their organs or tissues. Since most enteric viruses involved in outbreaks cannot grow in cell culture, studies using viral surrogate models are essential. Some species are proposed as surrogates for enteric viruses in environmental samples, including in bivalve mollusk samples, such as murine norovirus type 1 (MNV-1) and somatic (as φX) or F-specific coliphages (as MS2) bacteriophages. This study evaluated the tissue distribution of viral surrogates for enteric virus contamination after their bioaccumulation by Crassostrea gigas. Oyster tissues were analyzed for the distribution of viral surrogates (MNV-1, φX-174, and MS2) in digestive tissue (DT), gills (GL), and mantle (MT) after 4, 6, and 24 h of experimental bioaccumulation. MNV-1 had higher counts at 6 h in DT (1.2 × 103 PFU/g), followed by GL and MT (9.5 × 102 and 3.8 × 102 PFU/g, respectively). The bacteriophage φX-174 had a higher concentration in the MT at 4 and 6 h (3.0 × 102 PFU/g, in both) and MS2 in the GL after 24 h (2.2 × 102 PFU/g). The bioaccumulation pattern of MNV-1 by oysters was similar to the other enteric viruses (more in DT), while that of phages followed distinct patterns from these. Since the MNV-1 is bioaccumulated by C. gigas and is adapted to grow in cell culture, it is an important tool for bioaccumulation and viral inactivation tests in oysters. Although bacteriophage bioaccumulation was not similar to enteric viruses, they can be indicated for viral bioaccumulation analysis, analyzing MT and GL, since they do not bioaccumulate in DT.

Graduate Student Literature Review: Enterotoxigenic potential and antimicrobial resistance of staphylococci from Brazilian artisanal raw milk cheeses.

More than 30 types of artisanal cheeses are known in Brazil; however, microorganisms, such as Staphylococcus spp., can contaminate raw milk cheeses through different sources, from milking to processing. Staphylococcal food poisoning results from the consumption of food in which coagulase-positive staphylococci, mostly Staphylococcus aureus, have developed and produced enterotoxins. In addition, an emerging public health concern is the increasing antimicrobial resistance of some Staphylococcus strains. Furthermore, the ability of Staphylococcus spp. in sharing antibiotic resistance-related genes with other bacteria increases this problem. In light of these observations, this review aims to discuss the presence of, enterotoxins of, and antibiotic-resistant of Staphylococcus spp. in Brazilian artisanal cheese produced with raw milk.

Prevalence, distribution and environmental effects on faecal indicator bacteria and pathogens of concern in commercial shellfish production areas in a subtropical region of a developing country (Santa Catarina, Brazil).

This paper reviews recent literature on the abundance and distribution of faecal indicator bacteria and pathogens in shellfish production areas in the state of Santa Catarina, on the subtropical coast of Brazil. This state supplies > 95% of the national production of shellfish. Microbiological monitoring data were mapped using GIS and the results compared with those from other countries. Coastal human population is the main predictive parameter for faecal bacteria in the production areas. Temporal variations of the bacteria can also be predicted by solar radiation and rainfall. The prevalence of pathogens such as hepatitis A virus, human norovirus, Salmonella spp. and Vibrio spp. does not differ substantially from that in developed countries. The information reported here can be used to inform development of microbiological risk profiles for shellfish production areas.

Functional meat products: Trends in pro-, pre-, syn-, para- and post-biotic use.

In recent years, many studies have been conducted to develop functional meat products, focusing on strategies to maximize health-promoting compounds and reduce the presence of those that may cause negative impacts on the consumer's health. As such, the use of prebiotic, probiotic, and synbiotic agents in meat products has grown considerably. In addition, the use of new generation probiotics in meat products is a novel field that can be explored. With the most recent paraprobiotics/postbiotics update, several components could be tested in meat products. Some interventional studies using meat products added with biotic agents have shown great potential as functional foods by reducing the formation of nitrous compounds in the gut and improving the functionality of the gut microbiota. Although there are few studies focusing on synbiotic meat products, the results are also very promising in this field. As such, this review seeks to describe how probiotics, prebiotics, paraprobiotics and postbiotics can be employed in meat products to give them functional properties, as well as some of the major issues that may arise when using these agents.

Physicochemical properties and biological activities of bracatinga honeydew honey from different geographical locations.

Bracatinga (Mimosa scabrella Bentham) honeydew honey is a Brazilian dark honey in increasing international appreciation. In this sense, the knowledge of its composition and potential biological properties becomes indispensable. In the present study, the physicochemical characteristics, including mineral and phenolic composition, and the scavenging, reducing, and antimicrobial proprieties of bracatinga honeydew honey (bhh) from five different geographical locations, were investigated. Bhh proved to be a potential functional food due to its high content of minerals (up to 6395 mg kg-1) and phenolic compounds (up to 2393 µg 100 g-1) and high scavenging and reducing activities. High antimicrobial activity against four bacterial strains, with minimum inhibitory concentration values ranging from 10 to 60%, were also found. Additionally, through principal component analysis, partial discrimination of bhh was observed according to the geographical location, which favored the separation of samples from Lages, and mainly due to the presence of nectar in this honey, which was proposed for the samples from Bom Retiro. SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s13197-020-04937-x) contains supplementary material, which is available to authorized users.

Evaluation of the interaction between microencapsulated Bifidobacterium BB-12 added in goat's milk Frozen Yogurt and Escherichia coli in the large intestine.

Goat milk and goat milk and inulin were used as encapsulating agents of Bifidobacterium BB-12 and applied in Frozen Yogurt (GF2 and GF3, respectively) in order to evaluate the antagonistic effect against Escherichia coli. GF1 is a control containing only Escherichia coli. Simulation of gastrointestinal digestion occurred sequentially. Quantification of Bifidobacterium BB-12 was performed using plate counting while E. coli count was compared with quantification by qPCR with viable and nonviable cell differentiation. The Bifidobacterium BB-12 count was <1.0, 9.23 and 9.11 log CFU g-1 for GF1, GF2 and GF3, respectively. In the ascending colon, all samples showed E. coli counts of approximately 5 log CFU g-1 by plate counting and by qPCR. Throughout the transverse (24 h) and descending colon (48 h) samples GF2 and GF3 showed decrease in E. coli number. GF3 showed higher decrease of E. coli in the descending colon because of inulin bifidogenic characteristic. The production of organic acids by bifidobacteria was directly related to the decrease in the E. coli count. In plate counts, E. coli was not detected for the GF3 sample in the descending colon. However, when quantified by qPCR the sample presented amplification that corresponded to 3 log CFU g-1. In this way, it was possible to observe the phenomenon of the viable but not-culturable cells of E. coli. Finally, it is recommended the microcapsule produced with goat milk and the inulin for application in goat milk products, due to the better antagonist effect against E. coli.

Optimization of a propidium monoazide-qPCR method for Escherichia coli quantification in raw seafood.

The present study compared different concentrations of propidium monoazide (PMA), time of exposure to light and different light intensities to determine the optimal conditions for the quantification of viable Escherichia coli in cell suspension and in food matrix. The influence of cell density and the effectiveness of PMA in viable but non-culturable (VBNC) E. coli cells were evaluated and also applied in food matrix. For that purpose, different concentrations of PMA (20 µM, 40 µM, 50 µM, 60 µM and 80 µM) under different times of exposure (5 min, 10 min, 15 min, 20 min and 30 min) to lights of different intensities (500 W and 650 W) were evaluated. After determining the optimal conditions, the PMA-qPCR methods were applied to different compositions of live and heat-killed E. coli suspensions (v:v; 0:1; 1:0; 1:1) in concentrations ranging from 3 Log to 7 Log CFU/mL. The same dilutions were prepared with E. coli in VBNC state and applied in food matrix. The results obtained from qPCR, PMA-qPCR and plate counts were compared. The results suggested that a PMA treatment of 50 µM PMA for 15 min under 650 W light intensity was optimal under our conditions. For E. coli cell suspensions, the amplification of heat-killed cells was inhibited greatly by PMA when concentrations were ≤ 5 Log CFU/mL. For the samples of oyster inoculated with heat-killed cells, E. coli was not detected by PMA-qPCR in concentrations ≤4 Log CFU/g. Regarding the results with VBNC state, we considered the PMA-qPCR method to be applicable for enumerating E. coli VBNC cells in oyster samples. Based on our findings, we further recommend the use of PMA-qPCR with the aim of reducing the amplification of dead cells for improving its performance, since false-positives could still occur depending on the level of E. coli in the sample. The application of the PMA-qPCR for quantification of bacteria, compared to the use of culture-dependent methods, is quite promising. However, further studies are recommended, especially using different food matrices.

Development and application of a real-time polymerase chain reaction method for quantification of Escherichia coli in oysters (Crassostrea gigas).

Oysters are important mariculture species worldwide. Because of their filter-feeding behaviors, oysters can accumulate microorganisms, including pathogens, from surrounding water and concentrate bacteria in high numbers. Rapid and suitable methods for quantification of Escherichia coli in oysters are necessary considering that oysters are perishable foods often consumed raw and some countries use E. coli as the regulatory limit. The objective of this study was to develop a qPCR method for quantification of E. coli in oysters. Additionally, different methods were evaluated for DNA extraction from oyster samples and the more reliable method was chosen. Primers and probe were designed targeting uidA gene of E. coli and shown to specifically amplify DNA from E. coli. Standard curves with bacterial DNA extracted from oysters samples artificially inoculated with E. coli were conducted. A good correlation was noticed when the qPCR method was compared to a culture method in oyster samples. This is the first report of a method exclusively developed for direct quantification of E. coli in oyster, the method showed to be suitable for quantification of E. coli in oysters and could be useful in routine analyses, as it requires less time than the culture method.

Genotypic and phenotypic characterization of Escherichia coli isolated from mollusks in Brazil and the United States.

The aim of this study was to determine the serogroups, antimicrobial resistance and genetic diversity of Escherichia coli isolates from samples of bivalve mollusks collected along Santa Catarina coast, Brazil, and from the Chesapeake Bay, Maryland, USA. One hundred forty-one E. coli isolates were characterized for serogroups with 181 specific O antisera and antimicrobial susceptibility using the disk diffusion method. The genetic diversity was assessed using pulsed-field gel electrophoresis (PFGE). The results showed that among the isolates, 19.9% were classified as multi-drug resistant (MDR) and resistance was most frequently observed to cephalothin, nitrofurantoin, and ampicillin. The predominant serogroups were O6, O8, and O38. Some serogroups were recognized as pathogenic E. coli. PFGE dendrograms indicated extensive genetic diversity among the isolates. Although characteristics of the E. coli isolates were highly variable, it is important to note that E. coli belonging to pathogenic serogroups and MDR isolates are present in mollusks of both study areas. This is the first report on the phenotypic and genotypic characterization of E. coli from mollusks from Santa Catarina and the Chesapeake Bay that should encourage studies focusing on comparison of isolates across countries.

Occurrence of potentially pathogenic Vibrio in oysters (Crassostrea gigas) and waters from bivalve mollusk cultivations in the South Bay of Santa Catarina.

INTRODUCTION: This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfish in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. METHODS: Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. RESULTS: Twenty-nine (48.3%) oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnificus counts in the samples ranged from < 0.5 log10 Most Probable Number (MPN) g(-1) to 2.3 log10 MPN g(-1) oyster and from < 0.5 log10 MPN g(-1) to 2.1 log10 MPN g(-1) oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnificus in the samples ranged from < 0.3 log10 MPN·100mL(-1) to 1.7 log10MPN·100mL(-1) seawater and from < 0.3 log10 MPN·100mL(-1) to 2.0 log10 MPN·100mL(-1) seawater, respectively. A positive correlation between V. vulnificus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. CONCLUSIONS: The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfish.

Occurrence of potentially pathogenic Vibrio in oysters (Crassostrea gigas) and waters from bivalve mollusk cultivations in the South Bay of Santa Catarina

Introduction This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfish in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. Methods Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. Results Twenty-nine (48.3%) oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnificus counts in the samples ranged from < 0.5 log10 Most Probable Number (MPN) g–1 to 2.3 log10 MPN g–1 oyster and from < 0.5 log10 MPN g–1 to 2.1 log10 MPN g–1 oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnificus in the samples ranged from < 0.3 log10 MPN·100mL–1 to 1.7 log10MPN·100mL–1 seawater and from < 0.3 log10 MPN·100mL–1 to 2.0 log10 MPN·100mL–1 seawater, respectively. A positive correlation between V. vulnificus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. Conclusions The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfish. .

Evaluation of the PetrifilmTM EB and TEMPO® EB systems with ISO 21528-2:2004 method for the count of Enterobacteriaceae in milk

The development of alternative microbiological techniques is driven by the necessity to meet the current needs to deliver rapid results in the manufacturing process of foods, but it is important that these methods be evaluated for each application. The objective of the present study was to assess the PetrifilmTM EB and the TEMPO® EB systems with ISO 21528-2:2004 for the count of Enterobacteriaceae in pasteurized and UHT milk samples. We analyzed the microflora of 141 pasteurized milk samples, 15 samples of artificially contaminated pasteurized milk and 15 samples of artificially contaminated UHT milk. Investigation of the method PetrifilmTM EB and ISO 21528:2 regression analysis showed a high correlation in the samples, r = 0.90 for the microflora of pasteurized milk, r = 0.98 for artificially contaminated pasteurized milk and r = 0.99 for the artificially contaminated UHT milk. In evaluating the system TEMPO EB ® method and ISO 21528:2 correlation was also significant in the analyzed samples, with r = 0.86 for the microflora of pasteurized milk, r = 0.96 for artificially contaminated pasteurized milk and r = 0.99 for artificially contaminated UHT milk. No statistically significant differences were observed between the three methods conducted to analyze artificially contaminated pasteurized and UHT milk at three inoculum levels. In conclusion, the PetrifilmTM EB system and the TEMPO® EB system may be an alternative to the ISO 21528-2:2004 for the Enterobacteriaceae assay for milk as because of the ease-of-operation and the time reduction achieved for conducting the microbiological assay using these systems.

Evaluation of the Petrifilm™ EB and TEMPO(®) EB systems with ISO 21528-2:2004 method for the count of Enterobacteriaceae in milk.

The development of alternative microbiological techniques is driven by the necessity to meet the current needs to deliver rapid results in the manufacturing process of foods, but it is important that these methods be evaluated for each application. The objective of the present study was to assess the Petrifilm™ EB and the TEMPO(®) EB systems with ISO 21528-2:2004 for the count of Enterobacteriaceae in pasteurized and UHT milk samples. We analyzed the microflora of 141 pasteurized milk samples, 15 samples of artificially contaminated pasteurized milk and 15 samples of artificially contaminated UHT milk. Investigation of the method Petrifilm™ EB and ISO 21528:2 regression analysis showed a high correlation in the samples, r = 0.90 for the microflora of pasteurized milk, r = 0.98 for artificially contaminated pasteurized milk and r = 0.99 for the artificially contaminated UHT milk. In evaluating the system TEMPO EB ® method and ISO 21528:2 correlation was also significant in the analyzed samples, with r = 0.86 for the microflora of pasteurized milk, r = 0.96 for artificially contaminated pasteurized milk and r = 0.99 for artificially contaminated UHT milk. No statistically significant differences were observed between the three methods conducted to analyze artificially contaminated pasteurized and UHT milk at three inoculum levels. In conclusion, the Petrifilm™ EB system and the TEMPO(®) EB system may be an alternative to the ISO 21528-2:2004 for the Enterobacteriaceae assay for milk as because of the ease-of-operation and the time reduction achieved for conducting the microbiological assay using these systems.

Depuration of Oysters (Crassostrea gigas) contaminated with Vibrio parahaemolyticus and Vibrio vulnificus with UV light and chlorinated seawater.

The efficacy of depuration using UV light and chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus from oysters was investigated. Oysters were contaminated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus to levels of 10(4) to 10(5) CFU ml(-1) for bioaccumulation. The depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. Counts of V. parahaemolyticus or V. vulnificus were determined at 0, 6, 18, 24, and 48 h. Three treatments were conducted: T1, control treatment; T2, UV treatment; and T3, UV plus chlorine treatment. After 48 h of depuration of V. parahaemolyticus, T3 reduced the count by 3.1 log most probable number (MPN) g(-1) and T2 reduced the count by 2.4 log MPN g(-1), while T1 reduced the count by only 2.0 log MPN g(-1). After 48 h of depuration of V. vulnificus, T2 and T3 were efficient, reducing the counts by 2.5 and 2.4 log MPN g(-1), respectively, while T1 reduced the count by only 1.4 log MPN g(-1). The UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. The present study is the first report showing the efficacy of depuration systems for decontaminating V. parahaemolyticus and V. vulnificus in oysters cultivated on the Brazilian coast. This study provides information on processes that can contribute to controlling and preventing such microorganisms in oysters and could be used for effective postharvest treatment by restaurants and small producers of oysters on the coast of Brazil.

Microbiological quality of pre-cooked seafood marketed in Santa Catarina Island, Brazil / Qualidade microbiológica de frutos do mar pré-cozidos comercializados na Ilha de Santa Catarina, Brasil

The present study assessed the microbiological quality of pre-cooked and refrigera ted sea food marketed in Santa Catarina Island, Brazil. Forty-eight samples of crabs, mussels, shrimp and clams were purchase dat fish markets in Santa Catarina Island from June to September 2008. Microbiological analysis were conducted for total counts of psychrotrophic, coliforms at 45 °C, Enterococcus spp., Escherichia coli, coagulase-positive staphylococci and Salmonella spp. detecting. All of analyzed samples showed absenceof Salmonella spp. in 25g. Two (4.2 per cent) samples exceeded the counting limits of coliforms at 45 °C (one ofmussel and one of crab meat), and nine (18.75 per cent) samples (five of clams and four of crab meat) exceeded the limits for coagulase-positive staphylococci. The psychrotrophic counts were high in all products analyzed. Positive correlations were found between coliforms counting at 45 °C and Escherichia coli, but no correlation was found between Enterococcus spp. and coliforms at 45 °C or Escherichia coli. This study evidenced that about 20 per cent of the samples were not comply with the sanitary standards established by the Brazilian legislation.

Atividade antimicrobiana de Lactobacillus reuteri contra bactérias de interesse alimentar / Antimicrobial activity of Lactobacillus reuteri against bacteria of nourishment concern

Lactobacillus reuteri é uma espécie heterofermentativa que reside nos tratos gastrointestinal (GI), vaginale oral do homem e de outros animais de sangue quente. A ação probiótica de L. reuteri é atribuída a sua capacidade de exercer um efeito inibitório sobre micro-organismos patogênicos pela combinação de diversos mecanismos, incluindo-se a produção de ácido lático, peróxido de hidrogênio e produção de bacteriocinas. A reuterina é um composto neutro, de baixo peso molecular, solúvel em água, ativa em uma larga faixa de pH e resistente a ação de enzimas proteolíticas e lipolíticas. Neste estudo foi avaliado o efeito inibitório de L. reuteri sobre bactérias patogênicas ou deteriorantes de alimentos. L. reuteri apresentou capacidadede inibir o crescimento de Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus e Vibrio cholerae. Sugere-se que o antimicrobiano produzido pelo L. reuteri seja a reuterina.

Lactobacillus reuteri is a heterofermentative species that lives in the gastrointestinal (GI), vaginal and oraltracts of humans and other warm-blooded animals. The action of probiotic L. reuteri is derived from itsability to exert an inhibitory effect on pathogens, combining several mechanisms, including the productionof lactic acid, hydrogen peroxide and bacteriocin production. The reuterin is a neutral compound of lowmolecular weight, water soluble, active in a wide pH range, and resistant to proteolytic and lipolytic enzymes.This study evaluated the inhibitory effect of L. reuteri on pathogenic bacteria or food deterioration. L. reuterishowed ability to inhibit the growth of Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteusvulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus and Vibrio cholerae. Itis suggested that the antibiotic produced by L. reuteri is the reuterin.Key words. reuterin, L. reuteri, antimicrobial activity.

Atividade antimicrobiana de Lactobacillus reuteri contra bactérias de interesse alimentar / Antimicrobial activity of Lactobacillus reuteri against bacteria of nourishment concern

Lactobacillus reuteri é uma espécie heterofermentativa que reside nos tratos gastrointestinal (GI), vaginale oral do homem e de outros animais de sangue quente. A ação probiótica de L. reuteri é atribuída a sua capacidade de exercer um efeito inibitório sobre micro-organismos patogênicos pela combinação de diversos mecanismos, incluindo-se a produção de ácido lático, peróxido de hidrogênio e produção de bacteriocinas. A reuterina é um composto neutro, de baixo peso molecular, solúvel em água, ativa em uma larga faixa de pH e resistente a ação de enzimas proteolíticas e lipolíticas. Neste estudo foi avaliado o efeito inibitório de L. reuteri sobre bactérias patogênicas ou deteriorantes de alimentos. L. reuteri apresentou capacidadede inibir o crescimento de Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus e Vibrio cholerae. Sugere-se que o antimicrobiano produzido pelo L. reuteri seja a reuterina.

Lactobacillus reuteri is a heterofermentative species that lives in the gastrointestinal (GI), vaginal and oraltracts of humans and other warm-blooded animals. The action of probiotic L. reuteri is derived from itsability to exert an inhibitory effect on pathogens, combining several mechanisms, including the productionof lactic acid, hydrogen peroxide and bacteriocin production. The reuterin is a neutral compound of lowmolecular weight, water soluble, active in a wide pH range, and resistant to proteolytic and lipolytic enzymes.This study evaluated the inhibitory effect of L. reuteri on pathogenic bacteria or food deterioration. L. reuterishowed ability to inhibit the growth of Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteusvulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus and Vibrio cholerae. Itis suggested that the antibiotic produced by L. reuteri is the reuterin.Key words. reuterin, L. reuteri, antimicrobial activity.