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.(AU)

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. (AU)

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.(AU)

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.(AU)