Occurrence and antimicrobial resistance patterns of Listeria monocytogenes isolated from vegetables

Although the consumption of fresh and minimally processed vegetables is considered healthy, outbreaks related to the contamination of these products are frequently reported. Among the food-borne pathogens that contaminate vegetables is Listeria monocytogenes, a ubiquitous organism that exhibits the ability to survive and multiply at refrigerated temperatures. This study aimed to evaluate the occurrence of L. monocytogenes in vegetables as well as the antimicrobial resistance of isolates. The results showed that 3.03% of samples were contaminated with L. monocytogenes, comprising 2.22% of raw vegetables and 5.56% of ready-to-eat vegetables. Multiplex PCR confirmed the virulence potential of the isolates. Antimicrobial resistance profiling showed that 50% of the isolates were susceptible to the antibiotics used. The resistance of one isolate to penicillin G, a commonly employed therapeutic agent, and the presence of serotype 4b, a serotype commonly associated with food-borne outbreaks, could be potential health hazards for consumers.(AU)

Listeria monocytogenes em hortaliças: isolamento e sorotipagem / Listeria monocytogenes in green vegetables: isolation and serotyping

A ingestão de alimentos contaminados com Listeria monocytogenes representa um risco à saúde humana. A pesquisa de L. monocytogenes por meio de técnica de enriquecimento seletivo foi efetuada em 97 amostras de hortaliças, comercializadas no Estado do Rio de Janeiro. Foram analisadas 35 hortaliças in natura, 32 minimamente processadas e 30 pratos de saladas cruas prontas para consumo. Os isolados foram sorotipados por soroaglutinação clássica utilizando-se antissoro policlonal flagelar e somático.Sete amostras (7,2 %) apresentaram L. monocytogenes, sendo duas hortaliças in natura e cinco em forma de salada. Todos os isolados foram identificados como sorovar 1/2a. Em virtude da ocorrência de contaminação de hortaliças in natura com L. monocytogenes, é fundamental que os consumidores estejam esclarecidos quanto à possível presença deste patógeno nesse tipo de alimento, e ficarem cientes quanto à realização de corretos procedimentos de sanitização e de cuidados para evitar a contaminação cruzada com outros alimentos. A presença de L. monocytogenes em saladas prontas para consumo representa um risco à saúde dos consumidores, principalmente para indivíduos pertencentes ao grupo de risco.(AU)

Consumption of food contaminated with Listeria monocytogenes poses as a risk to human health. Ninety-seven samples of green leafy vegetables marketed in the state of Rio de Janeiro were analyzed for detecting L. monocytogenes by selective enrichment. Thirty-five in natura green vegetables, 32 minimally processed samples and 30 ready-to-eat raw salads samples were assessed. The isolates were serotyped by means of classical seroagglutination technique using somatic and flagellar polyclonal antisera. Seven samples (7.2 %) showed to be contaminated with L. monocytogenes, being two in naturasamples and five ready-to-eat salads. All isolates were identified as serovar 1/2a. Considering these findings on the contamination of in natura green vegetables with L. monocytogenes, the consumers should be advised regarding to the possibility of this kind of product to be contaminated with this pathogen, and also to imply vigilance in observing the proper sanitization procedures to avoid the cross-contamination with other foods. Occurrence of L. monocytogenes in ready-to-eat salad samples denotes a health hazard to consumers, especially to those who belong to risk groups.(AU)

Análise parasitológica de hortaliças minimamente processadas / Parasitological analysis of minimally processed vegetables

Os alimentos, principalmente as hortaliças in natura, constituem um importante veículo de contaminação parasitológica. Isto se deve ao fato de formas inadequadas de cultivo, manipulação e higienização, tomando- -se um problema de Saúde Pública. O presente estudo objetivou analisar a incidência de parasitas intestinais em variedades de alfaces e rúcula antes e após serem minimamente processadas. As amostras foram coletadas de um produtor na Cidade de Belo Horizonte - MG e foram analisadas pela técnica de enxaguadura, seguida de sedimentação espontânea por 24h e sedimentação por centrifugação. Os resultados demonstraram que todas as amostras de hortaliças não processadas analisadas estavam contaminadas por diferentes espécies I de cistos de protozoários e larvas de helmintos. As hortaliças minimamente processadas não se apresentaram isentas de contaminação por parasitas intestinas, e a analise evidenciou contaminação por E. coli e por Giardia lamblia, em especial a amostra de rúcula. Tanto as hortaliças não processadas quanto as minimamente processadas apresentaram qualidade higienicossanitátia comprometida, tomando necessaria a orientação aos produtores e manipuladores quanto à adequada higienização. Minimizando desta forma a transmissão de doenças parasitárias veiculadas por alimentos que são consumidos in natura. (AU)

The food, especially fresh vegetables, are an important vehicle of parasitological contamination. This is because of inadequate methods of cultivation, handling and hygiene, becoming a public health problem. This study aimed to assess the incidence of intestinal parasites in varieties of lettuces and arugula before and after they are minimally processed, the collected samples were collected from a producer in the city of Belo Horizonte -MG. These vegetables were analyzed using a rinse, followed by spontaneous sedimentation in 24hand sedimentation centrifugation. The results showed that all samples of unprocessed vegetables analyzed were contaminated with one or more types protozoan cysts and larvae of helminths. The minimally processed vegetables were not presented free of contamination by intestinal parasites, and analysis showed contamination by E. coli and Giardia lamblia, in particular sample of arugula. Both unprocessed vegetables and minimally processed showed the sanitary quality compromised, requiring guidance to producers and handlers regarding proper hygiene. Thus minimizing the transmission of parasitic diseases transmitted by foods that are consumed raw. (AU)

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Occurrence and genetic characterization of Listeria spp. in minimally processed vegetables commercialized in Porto Alegre, Brazil

Minimally processed vegetables go through many steps before they are refrigerated, selection, washing, peeling, cutting, disinfection and finally packaging. However, if no care is taken at the origin of the raw materials and in the processing stages, there is a chance of finding pathogenic bacteria, such as Listeria monocytogenes, which are able to grow at low temperatures. The aim of this research was to verify the occurrence of Listeria sp. in minimally processed vegetables sold in Porto Alegre, Brazil, and the genetic relationship among the isolates. Minimally processed salads were sampled monthly from local supermarkets and analyzed by inoculation on Listeria Enrichment Broth and subsequent seeding on two selective media, Palcam and Modified Oxford Agar. The typical colonies were identified to species level and their intergenic region 16S-23S rDNA were amplified in order to verify the genetic variability. Species of Listeria were found in 23 of the 52 processed salad samples analyzed and L. monocytogenes was found in seven. The presence of L. monocytogenes in the samples is a health concern, as these salads are eaten without further treatment by the consumer. The amplification of the intergenic region 16S-23S rDNA, showed a great genetic diversity among the isolates, with 43 different patterns, proving the usefulness of this technique in epidemiologic studies.

Análise microbiológica de vegetais e hortaliças minimamente processados / Microbiological analysis of vegetables and hortaliças most minimum prosecuted

Foram analisadas 10 amostras de vegetais e hortaliças minimamente processadas, comercializadas em hipermercados da cidade de Londrina-PR. As análises microbiológicas realizadas foram a determinação de coliformes totais e fecais, através da técnica do Numero Mais Provável (NMP) e presença de Escherichia coli através de análises bioquímicas de identificação. Os resultados obtidos para bactérias do grupo dos coliformes mostraram que 100 por cento das amostras estavam contaminadas por estes microrganismos, sendo que 80 por cento apresentaram-se fora do padrão estabelecido para coliformes fecais. Foi constatada a presença de E. coli em 80 por cento das amostras analisadas. Proteus e Enterobacter foram detectados em 20 por cento.(AU)

Were analysed 10 samples of minimally processed raw vegetables comercialyzed in Londrina-PR. The analysis of total and fecal coliforms and Escherichia coli, was realized with Most Problable Number and bioquimical identification. The results obtained for total coliform and fecal showed that 100% of the samples was contaminated, and 80% found out of the standard. E. coli was present in 80% of the samples, Proteus and Enterobacter was in 20%. (AU)

Implementação do sistema de análise de perigos e pontos críticos de controle (APPCC) para o controle de qualidade de produtos minimamente processados / Implementation of the analysis system and control critics (APPCC) for the products quality control most minimum prosecuted

A presença de bactérias, mofos e leveduras deteriorantes e patogênicos em vegetais frescos minimamente processados, vem sendo preocupação constante do risco de toxinfecções alimentares que possam ser oriundos do consumo destes produtos, considerando que o principal objetivo do processamento mínimo é fornecer à população um produto natural que conserve seu princípio nutritivo e possa ser ingerido cru. Sendo assim, centrar nossos interesses em todos os fatores que influenciam direta ou indiretamente na inocuidade e na qualidade desses produtos, é fundamental. A implementação de uma metodologia baseada na análise de perigos e riscos potenciais que viabilizem práticas efetivas de controle, monitoramento e verificação destes, é fundamental para garantir não só a qualidade do produto como a segurança do consumidor.(AU)

The presence of spoilage and pathogenic bacteria, moulds and yeasts in minimally processed fresh vegetables has been a constant concern of the risk of food poisoning which may be from the consumption of these products, taking into account that the main objective of minimal processing is furnish to populations a natural product which keeps its nutritive principles and may be eaten raw. 50, focusing our interests on all the factors which influence either directly or indirectly the harmlessness and quality of those products is fundamental. The implementation of a methodology based upon the analysis of dangers and potential risks which make effective practices, monitoring and verification of these is fundamental to warrant not only the quality of the product as well as the consumer's safety. (AU)