Microrganismos psicrotróficos em leites submetidos à ultra alta temperatura adquiridos em Curitiba, Paraná / Psychrotrophic bacteria in ultra-high-temperature milk acquired in Curitiba, Paraná

O tratamento do leite em ultra alta temperatura (UAT) possibilita a eliminação de patógenos e aumento do tempo de prateleira, no entanto, bactérias psicrotróficas são associadas a efeitos negativos no produto, como lipólise, rancificação e a geleificação. Resultado da resistência de alguns esporos ao processamento, e à possível atividade residual de enzimas termorresistentes. Assim, o objetivo deste estudo foi enumerar bactérias psicrotróficas e realizar a prova de lactofermentação em leites UAT comercializados na região de Curitiba, Paraná. Foram adquiridas 60 amostras de duas marcas (30 da marca A e 30 da marca B) quinzenalmente em três diferentes momentos. Em cada momento 10 amostras de um mesmo lote eram separadas em dois grupos (D0 e D7), sendo D0: cinco amostras avaliadas no dia da compra, e D7: cinco amostras avaliadas após incubação a 37± 1ºC/7 dias e analisadas quanto à enumeração de bactérias psicrotróficas, coloração de Gram e prova da lactofermentação. Em D0, uma (3,4%) amostra (marca A) apresentou crescimento de psicrotróficos (2,50 x 105 UFC/mL), Gram negativos. As amostras da marca B não apresentaram crescimento microbiano. Vinte e cinco (83,3%) amostras não formaram coágulo, e cinco (16,7%) produziram coágulo esponjoso. Em D7, nenhuma amostra apresentou contagem bacteriana, 20 (66,7%) não produziram coágulo e 10 (33,3%) produziram coágulo esponjoso. O processo UAT utilizado pela marca A não garantiu efetividade na redução de bactérias psicrotróficas, e o resultado do teste de lactofermentação indica a possível contaminação por coliformes em ambas as marcas. Ainda, a ausência de coágulos em diversas amostras pode ser um indicativo do uso de conservantes, o que é considerado fraude.

The beneficial effects of ultra-pasteurization milk treatment include elimination of milk pathogens, besides increasing the product's shelf-life, however, psychrotrophic bacteria are associated with several negative effects in the final product such as lipolysis, rancidification and gelation. This results from heat-resistant spores and its possible residual extracellular heat-resistant enzymes activity. With that in mind, this paper aimed to quantify psychrotrophic bacteria and perform a milk clotting test in UHT milk sold in Curitiba, Paraná. 60 samples from two brands were acquired (30 from A brand and 30 from B brand) each 15 days in different moments. Each time, 10 samples from a same batch were separated in two groups (D0 and D7), being D0: five samples analyzed in the purchase day, and D7: five samples analyzed after incubation at 37± 1ºC/7 days and evaluated regarding enumeration of psychrotrophic bacteria, Gram staining and milk clotting test. The heat-treating process effectiveness was evaluated by analyzing 30 samples from each brand, A and B, totalizing 60, being 10 from each different production batches, through the surface inoculation method in PCA, milk clotting test and classification of the isolated colonies by the Gram method. In D0, one (3,4%) sample (from A brand) resulted in Gram negative psychrotrophic growing (2,50 x 105 UFC/mL) . Samples from B brand did not result in bacterial growth. 25 samples (83,3%) did not clot, and five (16,7%) produced sponge clots. In D7, none of the samples presented bacterial growth, 20 (66,7%) did not clot and 10 (33,3%) produced sponge clots. Mesophilic bacterial culture was not done. The A brand UHT process did not grant sterilization regarding psychrotrophic bacteria, and the milk clotting results indicate possible coliforms contamination in both brands. Furthermore, clot absence in several samples could indicate preservatives usage, which is considered fraud.

Microrganismos psicrotróficos em leites submetidos à ultra alta temperatura adquiridos em Curitiba, Paraná / Psychrotrophic bacteria in ultra-high-temperature milk acquired in Curitiba, Paraná

O tratamento do leite em ultra alta temperatura (UAT) possibilita a eliminação de patógenos e aumento do tempo de prateleira, no entanto, bactérias psicrotróficas são associadas a efeitos negativos no produto, como lipólise, rancificação e a geleificação. Resultado da resistência de alguns esporos ao processamento, e à possível atividade residual de enzimas termorresistentes. Assim, o objetivo deste estudo foi enumerar bactérias psicrotróficas e realizar a prova de lactofermentação em leites UAT comercializados na região de Curitiba, Paraná. Foram adquiridas 60 amostras de duas marcas (30 da marca A e 30 da marca B) quinzenalmente em três diferentes momentos. Em cada momento 10 amostras de um mesmo lote eram separadas em dois grupos (D0 e D7), sendo D0: cinco amostras avaliadas no dia da compra, e D7: cinco amostras avaliadas após incubação a 37± 1ºC/7 dias e analisadas quanto à enumeração de bactérias psicrotróficas, coloração de Gram e prova da lactofermentação. Em D0, uma (3,4%) amostra (marca A) apresentou crescimento de psicrotróficos (2,50 x 105 UFC/mL), Gram negativos. As amostras da marca B não apresentaram crescimento microbiano. Vinte e cinco (83,3%) amostras não formaram coágulo, e cinco (16,7%) produziram coágulo esponjoso. Em D7, nenhuma amostra apresentou contagem bacteriana, 20 (66,7%) não produziram coágulo e 10 (33,3%) produziram coágulo esponjoso. O processo UAT utilizado pela marca A não garantiu efetividade na redução de bactérias psicrotróficas, e o resultado do teste de lactofermentação indica a possível contaminação por coliformes em ambas as marcas. Ainda, a ausência de coágulos em diversas amostras pode ser um indicativo do uso de conservantes, o que é considerado fraude.(AU)

The beneficial effects of ultra-pasteurization milk treatment include elimination of milk pathogens, besides increasing the product's shelf-life, however, psychrotrophic bacteria are associated with several negative effects in the final product such as lipolysis, rancidification and gelation. This results from heat-resistant spores and its possible residual extracellular heat-resistant enzymes activity. With that in mind, this paper aimed to quantify psychrotrophic bacteria and perform a milk clotting test in UHT milk sold in Curitiba, Paraná. 60 samples from two brands were acquired (30 from A brand and 30 from B brand) each 15 days in different moments. Each time, 10 samples from a same batch were separated in two groups (D0 and D7), being D0: five samples analyzed in the purchase day, and D7: five samples analyzed after incubation at 37± 1ºC/7 days and evaluated regarding enumeration of psychrotrophic bacteria, Gram staining and milk clotting test. The heat-treating process effectiveness was evaluated by analyzing 30 samples from each brand, A and B, totalizing 60, being 10 from each different production batches, through the surface inoculation method in PCA, milk clotting test and classification of the isolated colonies by the Gram method. In D0, one (3,4%) sample (from A brand) resulted in Gram negative psychrotrophic growing (2,50 x 105 UFC/mL) . Samples from B brand did not result in bacterial growth. 25 samples (83,3%) did not clot, and five (16,7%) produced sponge clots. In D7, none of the samples presented bacterial growth, 20 (66,7%) did not clot and 10 (33,3%) produced sponge clots. Mesophilic bacterial culture was not done. The A brand UHT process did not grant sterilization regarding psychrotrophic bacteria, and the milk clotting results indicate possible coliforms contamination in both brands. Furthermore, clot absence in several samples could indicate preservatives usage, which is considered fraud.(AU)

Effect of the Inclusion of Organic Copper, Manganese, And Zinc in The Diet of Layers on Mineral Excretion, Egg Production, and Eggshell Quality

This study aimed at evaluating the replacement of inorganic copper, manganese, and zinc sources by organic sources in the diet of laying hens during the second laying cycle in trace mineral excretion, egg production, and eggshell quality. Two hundred and fifty 100-week-old Dekalb hens were distributed according to a completely randomized design into five treatments with five replicates of ten birds each. The control treatment consisted of a basal diet with all trace minerals in the inorganic form. The other treatments consisted of a basal diet with a mixture of the minerals copper, manganese, and zinc in the organic form with concentrations of 100%, 90%, 80%, and 70% of the levels of inclusion of inorganic mineral sources in the control treatment. Trace mineral excretion was determined in five layers per treatment by the method of total excreta collection. Excreta trace mineral contents were determined by atomic absorption spectrophotometry. Egg production and eggshell quality were determined by the mass of the eggs and the egg specific gravity, respectively. For all trace minerals examined, the dietary supplementation with organic sources reduced trace mineral excretion compared with the control group, even at 70% inclusion level, without compromising egg production or eggshell quality. The replacement of the inorganic trace mineral sources by organics source effectively reduced the excretion of copper, manganese, and zinc by laying hens in the second laying cycle.

Effect of the Inclusion of Organic Copper, Manganese, And Zinc in The Diet of Layers on Mineral Excretion, Egg Production, and Eggshell Quality

This study aimed at evaluating the replacement of inorganic copper, manganese, and zinc sources by organic sources in the diet of laying hens during the second laying cycle in trace mineral excretion, egg production, and eggshell quality. Two hundred and fifty 100-week-old Dekalb hens were distributed according to a completely randomized design into five treatments with five replicates of ten birds each. The control treatment consisted of a basal diet with all trace minerals in the inorganic form. The other treatments consisted of a basal diet with a mixture of the minerals copper, manganese, and zinc in the organic form with concentrations of 100%, 90%, 80%, and 70% of the levels of inclusion of inorganic mineral sources in the control treatment. Trace mineral excretion was determined in five layers per treatment by the method of total excreta collection. Excreta trace mineral contents were determined by atomic absorption spectrophotometry. Egg production and eggshell quality were determined by the mass of the eggs and the egg specific gravity, respectively. For all trace minerals examined, the dietary supplementation with organic sources reduced trace mineral excretion compared with the control group, even at 70% inclusion level, without compromising egg production or eggshell quality. The replacement of the inorganic trace mineral sources by organics source effectively reduced the excretion of copper, manganese, and zinc by laying hens in the second laying cycle.(AU)

MICRORGANISMOS PSICROTRÓFICOS EM LEITES SUBMETIDOS À ULTRA ALTA TEMPERATURA ADQUIRIDOS EM CURITIBA, PARANÁ

O tratamento do leite em ultra alta temperatura (UAT) possibilita a eliminação de patógenos e aumento do tempo de prateleira, no entanto, bactérias psicrotróficas são associadas a efeitos negativos no produto, como lipólise, rancificação e a geleificação. Resultado da resistência de alguns esporos ao processamento, e à possível atividade residual de enzimas termorresistentes. Assim, o objetivo deste estudo foi enumerar bactérias psicrotróficas e realizar a prova de lactofermentação em leites UAT comercializados na região de Curitiba, Paraná. Foram adquiridas 60 amostras de duas marcas (30 da marca A e 30 da marca B) quinzenalmente em três diferentes momentos. Em cada momento 10 amostras de um mesmo lote eram separadas em dois grupos (D0 e D7), sendo D0: cinco amostras avaliadas no dia da compra, e D7: cinco amostras avaliadas após incubação a 37± 1ºC/7 dias e analisadas quanto à enumeração de bactérias psicrotróficas, coloração de Gram e prova da lactofermentação. Em D0, uma (3,4%) amostra (marca A) apresentou crescimento de psicrotróficos (2,50 x 105 UFC/mL), Gram negativos. As amostras da marca B não apresentaram crescimento microbiano. Vinte e cinco (83,3%) amostras não formaram coágulo, e cinco (16,7%) produziram coágulo esponjoso. Em D7, nenhuma amostra apresentou contagem bacteriana, 20 (66,7%) não produziram coágulo e 10 (33,3%) produziram coágulo esponjoso. O processo U