Enterococcus isolados do Queijo do Marajó, Tipo Creme: Caracterização tecnológica, cinética de multiplicação, capacidade de adesão e resistência a sanitizantes

• Autor(a) principal: Figueiredo, Elaine Lopes
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/508
• topic: Queijo; Queijo - Microbiologia; Queijo - Contaminação; Biofilme; Cheese; Cheese - Microbiology; Cheese - contamination; Biofilm; CNPQ::CIENCIAS AGRARIAS::CIENCIA E TECNOLOGIA DE ALIMENTOS::CIENCIA DE ALIMENTOS

Among the micro-organisms of health indicators and the ability to adhere to and form biofilms on surfaces of food processing, are of the genus Enterococcus bacteria often present in artisanal cheeses, as cheese Marajó. This study aimed to: i) assess the technological characteristics of 40 isolates of lactic acid bacteria (LAB) of the Marajó Cheese, Cream type, ii) identifying genetic isolates 6, iii) determine the kinetic parameters of microbial multiplication (multiplication rate and time lag) of 3 isolates and your Pool, incubated at temperatures of 15 oC, 30 oC and 45 oC, iv) the adherence of 3 isolates and your Pool surfaces of stainless steel, polyethylene and polypropylene in 5 days contact (0 h, 6 h, 12 h, 18 h and 24 h), v) study the interaction between the surfaces and isolated and their Pool, through the characteristics of interfacial interaction, vi) evaluate the microtopography of surfaces stainless steel, polyethylene and polypropylene, and surfaces with adhesion of Enterococcus isolates and your Pool, and vii) evaluate the removal of three isolated and his Pool, attached to surfaces, subjected to three types of sanitizers (benzalkonium chloride, dichloroisocyanurate sodium and peracetic acid). The isolates were gram-positive, catalase negative, gas producers, with proteolytic activity and low acidifying activity. Most isolates showed high capacity of diacetyl (33 isolates) and gelatinous clot formation (35 isolates). The isolates underwent genetic characterization were identified as E. faecium and E. durans. The results of multiplication kinetics showed that the temperature of 30 oC, the BAL samples showed higher rates of multiplication (μ) and shorter lag phase, compared to temperatures of 15 oC and 45 oC. The number of adhered cells of Enterococcus increased with contact time for all tested surfaces. In the interval of 0 h to 24 h of contact, there was an increase in the number of adhered cells by more than 8 log cycles for stainless steel surfaces, more than 7 log cycles to the polyethylene surface, and an average of 6 log cycles polypropylene. Based on the values of the contact angle, the surfaces of stainless steel, polyethylene and polypropylene were classified as hydrophobic and hydrophilic surfaces of BAL. Based on the values of the variation of the overall free energy of interaction ), the surfaces of polypropylene and BAL were classified as hydrophilic, while the surfaces of stainless steel and polyethylene were classified as hydrophobic. The scanning electron microscopy allowed the visualization of surfaces and adhered bacteria on the three surfaces. Sanitizers benzalkonium chloride, sodium dichloroisocyanurate and peracetic acid at concentrations of 200 mg.L-1, 10 min action, reduced Enterococcus cells with an average > 7.72 RD for stainless steel, average > 7.17 RD for polyethylene and average > 5.62 RD for polypropylene. Thus, it can be said that, although Enterococcus present technological potential, this micro-organism when found in high concentrations is indicative of poor sanitary conditions.