Avaliação da eficiência de diferentes desinfetantes sobre biofilmes de Bacillus cereus em superfícies de aço inoxidável.
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2017-12-08
Autores
Silva, Higor Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
As espécies do grupo do Bacillus cereus são comumente ocorrentes na cadeia produtiva de leite e derivados e frequentemente estão envolvidas em doenças transmitidas por alimentos. Constituem uma preocupação constante à indústria de lácteos, por conta de sua capacidade de formar biofilmes em superfícies sólidas, ocasionando a contaminação persistente dos produtos processados e representando risco à saúde pública. Objetivou-se neste estudo verificar a distribuição e ocorrência de linhagens e genes específicos relacionados à formação de biofilmes de Bacillus cereus isolados dos diversos estágios da cadeia produtiva de leite e produtos lácteos, classifica-los quanto à potencialcialidade em formar biofilmes, e ainda, avaliar a atuação e eficiência do ácido peracético e do hipoclorito de sódio junto ao sistema “clean in place”, simulado em escala piloto, sobre biofilmes formados em superfícies de aço inoxidável em contato com o leite. Para tanto, foram isolados microrganismos do grupo do Bacillus cereus de propriedades leiteiras, industrias e produtos lácteos, identificados genes específicos (sipW, tasA, Spo0A e PlcR) por sequenciamento genômico e avaliada a capacidade de formar biofilmes em microplacas de poliestireno. Selecionou-se um isolado sabidamente produtor de biofilmes, e por meio de contaminação experimental, induziu-se a adesão em superfícies de cupóns de aço inoxidável, em três circunstâncias distintas, incluindo contaminação por esporos, células vegetativas, e contaminação seguida de pasteurização. Na sequencia, os cupons foram submetidos a ação do ácido peracético e do hipoclorito de sódio, aplicando-os no sistema “clean in place”, realizado em escala piloto. Dentre 69 isolados, 98,5% foram classificados como moderados produtores de biofilmes. Os isolados pertencem aos grupos filogenéticos II, III, IV, V e VI, e os genes em estudo apresentaram alta ocorrência entre os isolados, estando igualmente distribuídos ao longo de toda cadeia produtiva, inclusive nos produtos lácteos. A adesão dos microrganismos às superfícies dos cupons alcançou 6,3x105 a 3,1x107UFC/cm2, resultando entre 3,0x104 e 8,1x106UFC/cm2 ao final do processo de sanitização. Os resultados demonstraram que o controle de biofilmes é fundamental e igualmente importante nos diversos estágios da cadeia produtiva, mas especialmente nas operações de obtenção de leite, por possibilitar a redução da carga contaminante inicial e consequentemente promoção da segurança dos alimentos, já que uma vez instalados, estes microrganismos podem formar biofilmes e disserminar-se pela linha de processamento. A ação do ácido peracético e do hipoclorito de sódio demostraram desempenhos semelhantes nas 3 circunstâncias estudadas, mas não foram suficientemente eficazes nas condições do presente estudo, quando usados no sistema “Clean in place” para a remoção de B. cereus s.s. aderidos a superfícies de aço inoxidável do tipo AISI 304 submersas em leite.
Species included in B. cereus group are widely distributed in dairy environment and were frequently involved in foodborne diseases. They are considered as a concern for dairy industries despite they pose a risk for public health, also despite the able to biofilm formation on stainless steel surfaces, causing the persistent contamination of processed dairy products. This study aimed to investigate if specific strains and genes for biofilm formation are significantly distributed and overpresented in distinct stages of dairy production chain, classifies the potential for biofilm formation, and evaluate the performance and efficiency of peracetic acid and sodium hypochlorite, on a pilot scale simulated clean in place, on biofilms in the stainless steel surfaces in contact with milk. Bacillus cereus microorganisms from dairy farms, industries and dairy products were identified, specific genes (sipW, tasA, Spo0A and PlcR) were identified by genomic sequencing and to form biofilms was performed using polystyrene microplates. Was selected one isolate known to produce biofilms, and by means of experimental contamination, adhesion was induced on stainless steel coupon surfaces, in three different circumstances, including spore contamination, vegetative cells, and contamination followed by pasteurization. In the sequence, the coupons were subjected to the action of peracetic acid and sodium hypochlorite, applying them to the clean in place system, performed on a pilot scale. Among 69 isolates, 98.5% were classified as moderate biofilm producers. The isolates belong to phylogenetic groups II, III, IV, V and VI, and a high prevalence of genes was shown, which were well distributed to dairy production chain including dairy products. The adhesion of the microorganisms to the surfaces of the coupons reached 6.3x105 to 3.1x107CFU/cm2, resulting between 3.0x104 and 8.1x106CFU/cm2 at the end of the sanitization process. The results showed that the control of biofilms is fundamental and equally important in the various stages of the production chain, but especially in the operations of obtaining milk, by enabling the reduction of the initial contaminant load and consequently promotion of food safety, since once installed, these microorganisms can form biofilms and assay themselves through the processing line. The peracetic acid and sodium hypochlorite were similar performance, but were not sufficiently effective to control biofilms on conditions of this study, when used on a "clean in place" for the removal of B. cereus s.s. adhered to stainless steel surfaces of type AISI 304 submerged in milk.
Species included in B. cereus group are widely distributed in dairy environment and were frequently involved in foodborne diseases. They are considered as a concern for dairy industries despite they pose a risk for public health, also despite the able to biofilm formation on stainless steel surfaces, causing the persistent contamination of processed dairy products. This study aimed to investigate if specific strains and genes for biofilm formation are significantly distributed and overpresented in distinct stages of dairy production chain, classifies the potential for biofilm formation, and evaluate the performance and efficiency of peracetic acid and sodium hypochlorite, on a pilot scale simulated clean in place, on biofilms in the stainless steel surfaces in contact with milk. Bacillus cereus microorganisms from dairy farms, industries and dairy products were identified, specific genes (sipW, tasA, Spo0A and PlcR) were identified by genomic sequencing and to form biofilms was performed using polystyrene microplates. Was selected one isolate known to produce biofilms, and by means of experimental contamination, adhesion was induced on stainless steel coupon surfaces, in three different circumstances, including spore contamination, vegetative cells, and contamination followed by pasteurization. In the sequence, the coupons were subjected to the action of peracetic acid and sodium hypochlorite, applying them to the clean in place system, performed on a pilot scale. Among 69 isolates, 98.5% were classified as moderate biofilm producers. The isolates belong to phylogenetic groups II, III, IV, V and VI, and a high prevalence of genes was shown, which were well distributed to dairy production chain including dairy products. The adhesion of the microorganisms to the surfaces of the coupons reached 6.3x105 to 3.1x107CFU/cm2, resulting between 3.0x104 and 8.1x106CFU/cm2 at the end of the sanitization process. The results showed that the control of biofilms is fundamental and equally important in the various stages of the production chain, but especially in the operations of obtaining milk, by enabling the reduction of the initial contaminant load and consequently promotion of food safety, since once installed, these microorganisms can form biofilms and assay themselves through the processing line. The peracetic acid and sodium hypochlorite were similar performance, but were not sufficiently effective to control biofilms on conditions of this study, when used on a "clean in place" for the removal of B. cereus s.s. adhered to stainless steel surfaces of type AISI 304 submerged in milk.
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Palavras-chave
Produtos lácteos, Segurança dos alimentos, Sequenciamento genômico