Peligros microbiológicos relacionados con alimentos fermentados de elaboración artesanal comercializados en Tunja, Nariño y Cauca / Microbiological risks related to artisanal fermented foods marketed in Tunja, Nariño and Cauca

RESUMEN Varios factores intervienen en la calidad de los alimentos, como los físicos, químicos, nutricionales, sensoriales y microbiológicos. Este último es importante, ya que, afecta las propiedades organolépticas del producto terminado y, además, puede ocasionar riesgos de salud pública asociados a peligros microbiológicos. Colombia es un país rico en gastronomía, incluyendo alimentos fermentados de elaboración artesanal (AFEA), los cuales son una alternativa actual para sistemas agroalimentarios que buscan alimentos más naturales. El objetivo de este estudio fue evaluar los criterios microbiológicos en AFEA y el cumplimiento de requisitos sanitarios para sensibilizar a productores de bebidas artesanales y revalorizar los productos. Se tomaron en cuenta 11 productores artesanales de Masato, Champús y Almidón agrio de yuca en zonas rurales del país, que voluntariamente aceptaron participar. Se midieron los parámetros de pH, humedad, sólidos solubles y recuentos microbiológicos. Con estos resultados, se pudo calcular el porcentaje de conformidad de los alimentos, de los cuales el 36 % de productos evaluados fueron aptos para el consumo. Se incumplieron los límites establecidos para Escherichia coli, Staphylococcus aureus, Bacillus cereus y Salmonella sp. Los análisis fisicoquímicos mostraron que el Masato y el Champús aportan condiciones abióticas para el crecimiento microbiano. Además, los productores Almidón agrio de yuca tuvieron mayor valoración en el cumplimiento de requisitos sanitarios y menor cumplimiento que los productores de Champús. Los análisis realizados indican que la mayoría de los alimentos incumplieron los límites permitidos por lo cual se debe capacitar a los productores en buenas prácticas de manufactura.

ABSTRACT Several factors intervene in the quality of the food, such as physical, chemical, nutritional, sensory, and microbiological. The latter is important as it affects the sensory properties of the finished product, and it can also cause public health risks associated with microbiological hazards. Colombia is a country rich in gastronomy, including artisanal fermented foods (AFEA), which are a current alternative for agri-food systems seeking for more natural foods. The objective of this study was to evaluate the microbiological criteria in AFEA and its compliance with the sanitary requirements to raise the awareness among crafted beverages producers and revalue the products. Eleven artisan producers of masato, champús and sour cassava starch in rural areas of the country, who voluntarily agreed to participate, were considered. The parameters of pH, humidity, soluble solids, and microbiological counts were measured. With these results, it was possible to calculate the compliance rate of the food, from which 36% of the products evaluated were fit for consumption. The limits established for Escherichia coli, Staphylococcus aureus, Bacillus cereus and Salmonella spp were breached. Physicochemical analysis showed that Masato and Champús provide abiotic conditions for microbial growth. In addition, the Sour cassava starch producers had higher compliance ratings regarding sanitary requirements but lower compliance ratings than champús producers. The performed analysis indicates that most of the food did not comply with the permitted limits, which is why producers must be trained in good manufacturing practices.

Detection, genetic diversity and antibiotic resistance profiles of Bacillus cereus isolated from sago processing plants in Malaysia

Aims@#Bacillus cereus is a Gram-positive, rod-shaped and spore-forming bacterium. It is a ubiquitous bacterium which is widely distributed in several environments such as soil and plants and is commonly isolated from food and its processing environment. This study was aimed to determine the genetic diversity and antibiotic resistance of B. cereus isolated from sago processing in Sarawak. @*Methodology and results@#Out of 120 samples, 42 B. cereus isolates were detected with the presence of hly gene of B. cereus by using specific polymerase chain reaction (PCR). Twenty B. cereus isolates were randomly selected and further characterized by pulsed-field gel electrophoresis (PFGE) of chromosomal DNA digested with NotI to examine the genetic diversity. The result of the PFGE analysis confirmed that the B. cereus strains in sago processing were genetically diverse. Based on the dendrogram generated, B. cereus strains were grouped into two major clusters and these clusters were grouped together based on sources of isolation. The investigation on the antibiotic resistance of B. cereus strains revealed that the B. cereus strains were uniformly highly resistant to penicillin and ampicillin and highly susceptible to imipenem and norfloxacin. @*Conclusion, significance and impact of study@#The results of this study suggest that the B. cereus isolated from sago processing derived from a mixture of sensitive and resistant strains with diverse genetic contents.

Antimicrobial Activities of Omija Extracts Against Bacillus cereus and Escherchia coli

Omija berry (Schisandra fructus) is a traditional Korean fruit, which contains lots of medicinal ingredients. In order to analyze whether Omija contains antibacterial components, we extracted Omija using five different methods including water precipitation, ethanol precipitation, hot water extract, methanol-ultrasonication, and water-ultrasonication, and examined their antimicrobial activities against Escherichia coli (E. coli), and Bacillus cereus (B. cereus). Most of Omija extracts did not inhibit bacteria growth in the paper disc diffusion assay except hot water extract for 60 minutes. Hot water extract for 60 minutes made clear inhibition zone around the disc at all the concentrations (x1, x1/10, x1/100) in both E. coli and B. cereus. However, hot water extracts for 90 minutes and 120 minutes showed antimicrobial activities only at x1 stock solution, which indicates that 60 minutes extraction at hot water is the best method to obtain Omija extract with the best antimicrobial activities in disc diffusion assay. In turbidimetric assay, water extract in soak, hot water extract, and methanol extract in ultrasonicator inhibited growth of both E. coli and B. cereus. Ethanol extract in soak and water extract in ultrasonicator had no effect on bacterial growth in both E. coli and B. cereus. In this study, we found that Omija extracts showed antimicrobial activities against E. coli and B. cereus. Therefore, water soluble materials of Omija can be used as a drink supplement and developed as an antibacterial cleanser.

Distributions of Bacillus cereus, Pseudomonas, Enterococcus, and coliforms Isolated from Agricultural Products

A survey was conducted on the bacterial contamination levels from 128 agricultural products, and identified 31 coliforms, 34 Bacillus spp., 35 Pseudomonas spp., and 3 Enterococcus spp.. Antibiotic susceptibility testing of eight Escherichia coli (E. coli) isolates, thirteen Bacillus cereus (B. cereus) isolates and seven Pseudomonas aeruginosa (P. aeruginosa) reveled that none of the E. coli isolates shows multidrug resistance pattern. However, one B. cereus isolate was resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin, and twelve B. cereus isolates were resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin + Tetracycline. The data from the current study points out that many agricultural products contain multidrug resistant bacteria, and it can be suggested for the need of proper guidelines and special management on the use of antibiotics in agricultural products.

Distributions of Bacillus cereus, Pseudomonas, Enterococcus, and coliforms Isolated from Agricultural Products

A survey was conducted on the bacterial contamination levels from 128 agricultural products, and identified 31 coliforms, 34 Bacillus spp., 35 Pseudomonas spp., and 3 Enterococcus spp.. Antibiotic susceptibility testing of eight Escherichia coli (E. coli) isolates, thirteen Bacillus cereus (B. cereus) isolates and seven Pseudomonas aeruginosa (P. aeruginosa) reveled that none of the E. coli isolates shows multidrug resistance pattern. However, one B. cereus isolate was resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin, and twelve B. cereus isolates were resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin + Tetracycline. The data from the current study points out that many agricultural products contain multidrug resistant bacteria, and it can be suggested for the need of proper guidelines and special management on the use of antibiotics in agricultural products.

Estudio bacteriológico de sushi preparado y comercializado en San José, Costa Rica / Bacteriological study of prepared and commercialized sushi in San Jose, Costa Rica

Objetivo: Conocer la calidad bacteriológica de muestras de sushi expendidas en diferentes restaurantes de la provincia de San José en Costa Rica. Materiales y Método: Se analizaron 60 muestras de éste producto, a las cuales se les realizó mediante los procedimientos descritos en el Compendio de Métodos para el Examen Microbiológico de Alimentos, los siguientes análisis: recuento total aerobio mesófilo, número más probable de coliformes termotolerantes, fecales y E. coli, recuento de S. aureus y número más probable de B. cereus. Adicionalmente se investigó la presencia de patógenos relacionados con el sushi como: L. monocytogenes, Salmonella sp. y V parahaemolitycus. Resultados: El 6 (46%) establecimientos presentaron positividad por E coli, aunque en poca cantidad (1 a 10 NMP/ g en promedio). Siete establecimientos (54%) mostraron presencia de S. aureus, la mayoría en el orden de 10² UFC/ g. Adicionalmente, se logró aislar 2 cepas de B. cereus y2 de L. monocytogenes. No fue posible establecer la presencia de Salmonella sp. ni Vibrio parahaemolyticus en ninguna de las muestras evaluadas. Discusión: Según el Reglamento Técnico Centroamericano RTCA 67.04.50:08, en su sección 17.1 el 62% (8) de los establecimientos incluidos en el estudio incumplen con la norma establecida para este tipo de alimento. Esta no conformidad se da en la mayoría de los casos por la presencia de cantidades de S. aureus superiores a las 100 UFC/g.

Objective: Knowing the bacteriological quality of samples issued at different sushi restaurants in the province of San José in Costa Rica. Methods: Sixty sushi samples, acquired from different restaurants from the province of San José, Costa Rica were analyzed in order to determine their bacteriological quality. Methodology followed was that described in the Compendium of Methods for the Microbiological Examination of Food and included total aerobic plate count, Staphylococus aureus plate count, Most Probable Number of total and fecal coliforms, Escherichia coli, and B. cereus. Also, the presence of potential pathogens found in sushi including Salmonella sp., Listeria monocytogenes and Vibrio parahaemolyticus was analyzed. Results: That 6 (46%) of the restaurants were positive for E. coli, even though in small quantities (1 to to NMP/g average). S. aureus was isolated from seven restaurants (54%) also in small concentrations (10²CFU/g). In addition, two strains of B cereus and two of L monocytogenes were isolated. Neither Salmonella sp nor Vibrio parahaemolyticus were isolated from the samples evaluated. Discussion: According to the Central American Technical Regulation RTCA 67 04 50 08 sections 17.1 62% (8) of the restaurants included in this study do not comply with the regulations established for this kind of food. This nonconformity is due, mainly, to the presence of S aureus in concentrations greater than 100 CFU/g.

Phenotypic & genetic characterization of Bacillus cereus isolated from the acute diarrhoeal patients.

Background & objectives: Bacillus cereus is one of the pathogens responsible for human diarrhoea, mainly due to consumption of contaminated food. The present study was undertaken to determine the occurrence of B. cereus among diarrhoeal patients and its phenotypic and genetic characteristics that determine the virulence and clonal features. Methods: Stool specimens were collected for two years from acute diarrhoeal patients attending the two referral hospitals in Kolkata. Presence of virulence genes in B. cereus was determined by PCR. Clonality was assessed by pulsed-field gel analysis (PFGE) by restriction digestion with SmaI and NotI enzymes. Enterotoxins were detected by haemolysin assay and using BCET-RPLA kit. Invasion assay was done on Hep-2 cell line. Antimicrobial susceptibility was tested by disc diffusion method. Results: B. cereus was identified in 54 (3.5%) of the 1536 diarrhoeal cases studied. Majority of the isolates were susceptible to many antibiotics but showed resistant to amoxyclav and cephalosporins. Six genes covering the two different enterotoxic complexes determining the pathogenicity of B. cereus have been characterized by PCR. The nhe genes were detected in a higher proportion than hbl. Except in two, clonal diversity was noticed among 21 B. cereus isolates. Haemolytic enterotoxin was detected in 76 per cent of the isolates. Majority of the isolates (67%) produced in vitro enterotoxin (BCET) confirming its involvement in the infection. Interpretation & conclusions: Though the presence of B. cereus was not high in patients with diarrhoea, several virulence factors confirm their association with diarrhoea. Distinct clonality was identified in majority of the isolates indicating their origin from different sources.

Production and partial purification of protease by selected bacterial strains using raw milk as substrate

Aims: The present study was investigated to optimize and partially purify the proteases produced by the food borne bacterial strains. Methodology and Results: Four bacterial strains such as Bacillus cereus, Proteus vulgaris, P. mirabilis and Enterobacter aerogenes were isolated from food wastes. These strains were individually inoculated in to the formulated culture media supplied with three different concentrations (1:1 to 1:3) of raw milk as major substrate. Among the concentrations, 1:2 ratio of substrate supplied medium showed maximum (0.133 to 8.000 IU/mL) protease production by all the tested organisms. After optimization, the organisms were tested for protease production at various pH (3 to 9), and temperature (30 to 80 °C). The result showed that all the organisms were capable of producing maximum protease at pH 6 (8.533 to 10.133 IU/mL) and at 50 °C (8.666 to 10.666 IU/mL). The crude enzymes produced by the tested organisms were individually purified by two different methods viz sodium alginate and ammonium sulphate-butanol methods. The purity of the protease determined in these two methods was ranged between 3.24 to 5.44 I and 3.13 to 5.55 IU/mL respectively. The partially purified enzymes were further analysed through SDS-PAGE; accordingly the molecular weight of protein produced by the test organisms was determined in between 49.44 and 50.98 kDa. Conclusion, significance and impact of study: Among the tested strains P. vulgaris was identified as the major protease producer in optimized culture condition of 50o C and pH6. The molecular mass of the partially purified protease of P. vulgaris was 50.32 KDa. Further research on optimization of other fermentation parameters using statistical tools with P. vulgaris is needed to scale up the process.

A Case of Emetic Toxin Producing Bacillus cereusStrains Isolated from Outbreak / 대한임상미생물학회지

Bacillus cereus causes two types of gastrointestinal diseases: emesis and diarrhea. It produces one emetic toxin and nine different enterotoxins. In March 2008, eight of a family became sick after eating slices of raw fish. We isolated emetic toxin producing B. cereus from the stools of 6 patients and 2 subclincal humans. In this study, the presence of enterotoxin genes, such as those of haemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe), B. cereus enterotoxin T (BceT), enterotoxin FM (EntFM), cytotoxin K (cytK) and cereulide were assayed by polymerase chain reaction (PCR) methods. Their enterotoxin activities were assayed using the BCET- RPLA, Tecra ELISA kit and Hep-2 vacuole activity. Bacterial isolates were subtyped by pulsed-field gel electrophoresis (PFGE). This study demonstrates the emetic toxin-producing stains of B. cereus in clinical specimens, for the first time in the Republic of Korea.