The antimicrobial efficacy of Lippia alba essential oil and its interaction with food ingredients

The objective of this study was to evaluate the antimicrobial potential of Lippia alba essential oil (EOLa) and to investigate the effect of food ingredients on its efficacy. The antimicrobial potential of the oil was determined by the presence or absence of inhibition zones, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli, Listeria innocua, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus. The effect of food ingredients and the pH on the antimicrobial efficacy of oil was assessed by monitoring the maximum growth rate of Listeria monocytogenes in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1, 5, 3, 6 or 12%), sunflower oil (0, 5 or 10%) and TSB broth at pH levels of 4, 5, 6 or 7. The EOLa showed efficacy at all concentrations (50%, 25%, 6.25%, 3%, 1.5%, 0.8%, 0.4% and 0.2%) evaluated, against all bacterial species, Gram-positive and Gram-negative. The antimicrobial efficacy of EO was found to be a function of ingredient manipulation. Proteins and lipids had a negative impact on the oil effectiveness, indicating the protective action of both on the microbial specie tested. On the contrary, at the highest concentration of starch (10%), the lower rate growth of L. monocytogenes was detected, therefore indicating a positive effect of carbohydrates on the oil effectivenes. Regarding the pH, the studies showed that the rate of microbial growth increased with increasing pH. It was concluded that the use of EOLa is more effective control pathogenic and spoilage bacteria when applied to starchy foods under an acidic pH.

Avaliação da qualidade microbiológica de hortaliças minimamente processadas / Microbiological quality evaluation minimally processed vegetables

A microbiota é um fator de grande importância na qualidade e conservação de vegetais minimamente processados. Muitos microrganismos podem afetar adversamente a qualidade e a segurança desses produtos, considerando que microrganismos patogênicos, que normalmente não estariam presentes, passam a compor a microbiota contaminante decorrente do manuseio a que são submetidos. Objetivou-se, neste trabalho, determinar a qualidade microbiológica de hortaliças, anterior e posteriormente ao processo de sanitização, como também o período final da vida-de-prateleira dos produtos sanitizados, avaliando-se a presença de Listeria sp., Listeria monocytogenes e Salmonella sp. Foram analisadas amostras de agrião, alface, cenoura ralada, espinafre, repolho verde ralado e rúcula minimamente processados. As amostras não sanitizadas foram analisadas no dia da coleta, e as sanitizadas analisadas a 1, 5 e 8 dias após o processamento, a fim de determinar a condição microbiológica dos produtos. As hortaliças foram armazenadas sob temperatura de 5ºC. Salmonella sp. foi detectada em 12,7 por cento das amostras, enquanto L. monocytogenes não foi encontrada em nenhuma delas, embora outras espécies de Listeria tenham sido isoladas de alface e cenoura. A presença de Salmonella sp. tornaram 16 amostras impróprias para o consumo humano, de acordo com a RDC nº 12.

The microbiota is a factor of great importance to the quality and conservation of minimally processed vegetables. Many microorganisms may adversely affect the quality and safety of these products, considering that normally present pathogenic microorganisms may eventually compose the polluting microbiota whenever being submitted to handling. This work aimed to determine both: vegetable microbiologic quality, prior and post-sanitization process as well as products post-sanitization shelf-life expiring date, while the presence of Listeria sp., Listeria monocytogenes and Salmonella sp. was evaluated. The minimally processed vegetables samples analyzed were watercress, lettuce, grated carrot, spinach, grated green cabbage and rucula. The non-sanitized samples were analyzed on the first harvesting day (day 1), and the sanitized ones were analyzed at 1, 5 and 8 days after being processed in order to determine the product microbiological state. The vegetables were stored under a temperature of 5ºC. Salmonella sp. was detected in 12.7 percent of the samples, while L. monocytogenes was not found in any of them, though other species of Listeria were isolated from lettuce and carrot. According to the RDC nº 12, the presence of Salmonella sp. rendered 16 samples as being inappropriate for human consumption.

Boas práticas de fabricaçäo: uma alternativa para melhoria da qualidade de polpas congeladas de frutas / Good manufacturing practices: an alternative for the production of frozen fruit pulp

Considerando o aumento no mercado e a constante preocupaçäo com a qualidade dos produtos, as boas práticas de fabricaçäo tem sido uma ferramenta inovadora e eficaz na garantia da qualidade do produto final. A produçäo de polpa de fruta congelada no Nordeste tem crescido gradativamente, mas sem suporte técnico, acarretando produtos fora de padröes no que diz respeito a cor, sabor e outras reaçöes de origem microbiológica. O trabalho está sendo elaborado nas empresas produtoras do estado do Ceará, com objetivo de implantar as boas práticas de fabricaçäo nas unidades fabris e normatizar os procedimentos adotados para a qualidade em relaçäo a ambiente, pessoal, equipamentos, utensílios e processos em um manual de boas práticas.