RESUMO
The major contamination sources, biofilm-forming ability and biocide resistance of Staphylococcus aureus in tilapia-processing plants were evaluated. Twenty-five processing control points were analysed twice in two factories, including whole tilapias, frozen fillets, water and food-contact surfaces. No final product was contaminated with S. aureus. However, high concentrations of S. aureus carrying enterotoxin ( se) genes were found in several processing points of both factories due to the application of inadequate hygienic and handling procedures, which generate a high risk of cross-contamination of the tilapia fillets with staphylococcal enterotoxins. Nine S. aureus strains were characterized by RAPD-PCR using primers AP-7, ERIC-2 and S. A wide diversity of se gene profiles was detected, most strains being multi- se-carriers. All S. aureus strains showed high biofilm-forming ability on stainless steel and polystyrene. Biofilm-forming ability was correlated with the presence of fliC H7 and the type of origin surface (metallic or plastic). A marked resistance of S. aureus to peracetic acid and sodium hypochlorite was also observed, required doses being higher than those recommended by manufacturers to be eradicated. Case-by-case approaches are thus recommended to determine the sources and degree of contamination present in each factory, which would allow applying precise responses that avoid, or at least reduce, the presence of bacterial pathogens and the emergence of antimicrobial resistance.
Assuntos
Biofilmes/crescimento & desenvolvimento , Contaminação de Alimentos/prevenção & controle , Indústria de Processamento de Alimentos/instrumentação , Alimentos Congelados , Alimentos Marinhos , Staphylococcus aureus/fisiologia , Tilápia , Animais , Aquicultura , Carga Bacteriana , Biofilmes/efeitos dos fármacos , Brasil , Desinfetantes/farmacologia , Farmacorresistência Bacteriana Múltipla , Enterotoxinas/genética , Enterotoxinas/isolamento & purificação , Enterotoxinas/metabolismo , Flagelina/genética , Flagelina/isolamento & purificação , Flagelina/metabolismo , Alimentos Congelados/microbiologia , Testes de Sensibilidade Microbiana , Tipagem Molecular , Ácido Peracético/farmacologia , Poliestirenos , Alimentos Marinhos/microbiologia , Hipoclorito de Sódio/farmacologia , Aço Inoxidável , Staphylococcus aureus/classificação , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/isolamento & purificação , Tilápia/crescimento & desenvolvimento , Tilápia/microbiologia , Microbiologia da ÁguaRESUMO
The persistence of Listeria monocytogenes in food industry environments has been associated to the ability of specific isolates to produce biofilms. This study aimed to evaluate the biofilm production of 85 L. monocytogenes strains previously isolated from samples of cheese, brine and the environment of two cheese processing plants located in São Paulo, Brazil. The L. monocytogenes isolates belonged to serotypes 4b, 1/2b and 1/2c, yielded 30 different pulsotypes by pulsed-field gel electrophoresis (PFGE), and were submitted to biofilm-formation assays on polystyrene microplates and stainless steel coupons incubated statically at 35±0.5°C for 48h. All isolates from different sources showed ability to produce biofilms on polystyrene microplates, from which 21 (24.7%) also produced biofilms on stainless steel. Four isolates (4.7%) belonging to four different pulsotypes were classified as strong biofilms-producers on polystyrene microplates, while isolates belonging to four pulsotypes previously evaluated as persistent had weak or moderate ability to produce biofilms on polystyrene microplates. No relationship between the serotypes or pulsotypes and their biofilm-forming ability was observed. This study highlights the high variability in the biofilm production among L. monocytogenes strains collected from cheese and cheese-production environment, also indicating that strong biofilm-formation ability is not a key factor for persistence of specific isolates in cheese processing plants.
Assuntos
Biofilmes/crescimento & desenvolvimento , Queijo/microbiologia , Contaminação de Equipamentos , Contaminação de Alimentos , Microbiologia de Alimentos , Indústria de Processamento de Alimentos/métodos , Listeria monocytogenes/crescimento & desenvolvimento , Aderência Bacteriana , Brasil , Desenho de Equipamento , Indústria de Processamento de Alimentos/instrumentação , Listeria monocytogenes/classificação , Poliestirenos/química , Sais/análise , Aço Inoxidável/química , Propriedades de SuperfícieRESUMO
Legal mandates can play an important role in the success of rice fortification programs that involve the private sector. However, merely enacting mandatory legislation does not guarantee success; it requires a coordinated, multidimensional cross-sector effort that addresses stewardship, develops an appropriate rice fortification technology, enables sustainable production and distribution channels through a range of private-sector players, ensures quality, generates consumer demand, and monitors progress. Furthermore, economic sustainability must be built into the supply chain and distribution network to enable the program to outlast government administrations and/or time-limited funding. Hence, mandates can serve as valuable long-term enablers of cross-sector mobilization and collaboration and as catalysts of civil society engagement in and ownership of fortification programs. This paper compares the rice fortification experiences of Costa Rica and the Philippines--two countries with mandates, yet distinctly different industry landscapes. Costa Rica has achieved national success through strong government stewardship and active market development--key elements of success regardless of industry structure. With a comparatively more diffuse rice industry structure, the Philippines has also had success in limited geographies where key stakeholders have played an active role in market development. A comparative analysis provides lessons that may be relevant to other rice fortification programs.
Assuntos
Análise de Alimentos , Qualidade dos Alimentos , Alimentos Fortificados , Indústria de Processamento de Alimentos/métodos , Oryza , Costa Rica , Feminino , Indústria de Processamento de Alimentos/instrumentação , Indústria de Processamento de Alimentos/legislação & jurisprudência , Indústria de Processamento de Alimentos/normas , Humanos , Masculino , FilipinasRESUMO
Conveyor belts are widely used in food handling areas, especially in poultry processing plants. Because they are in direct contact with food and it is a requirement of the Brazilian health authority, conveyor belts are required to be continuously cleaned with hot water under pressure. The use of water in this procedure has been questioned based on the hypothesis that water may further disseminate microorganisms but not effectively reduce the organic material on the surface. Moreover, reducing the use of water in processing may contribute to a reduction in costs and emission of effluents. However, no consistent evidence in support of removing water during conveyor belt cleaning has been reported. Therefore, the objective of the present study was to compare the bacterial counts on conveyor belts that were or were not continuously cleaned with hot water under pressure. Superficial samples from conveyor belts (cleaned or not cleaned) were collected at three different times during operation (T1, after the preoperational cleaning [5 a.m.]; T2, after the first work shift [4 p.m.]; and T3, after the second work shift [1:30 a.m.]) in a poultry meat processing facility, and the samples were subjected to mesophilic and enterobacterial counts. For Enterobacteriaceae, no significant differences were observed between the conveyor belts, independent of the time of sampling or the cleaning process. No significant differences were observed between the counts of mesophilic bacteria at the distinct times of sampling on the conveyor belt that had not been subjected to continuous cleaning with water at 45°C. When comparing similar periods of sampling, no significant differences were observed between the mesophilic counts obtained from the conveyor belts that were or were not subjected to continuous cleaning with water at 45°C. Continuous cleaning with water did not significantly reduce microorganism counts, suggesting the possibility of discarding this procedure in chicken processing.
Assuntos
Galinhas/microbiologia , Contaminação de Equipamentos/prevenção & controle , Indústria de Processamento de Alimentos/instrumentação , Indústria de Processamento de Alimentos/métodos , Higiene , Água/farmacologia , Animais , Contagem de Colônia Microbiana , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos , Indústria de Processamento de Alimentos/normas , HumanosRESUMO
Biofilm formation is a matter of concern in food industries because biofilms facilitate the survival of pathogenic bacteria such as Listeria monocytogenes, which may contaminate food-processing equipment and products. In this study, nisin and two Enterococcus faecium strains were evaluated for their effect on biofilm formation by L. monocytogenes cultured in brain heart infusion broth and on stainless steel coupons. Elimination of preformed L. monocytogenes biofilms by peroxyacetic acid also was tested. Adhesion control experiments were performed with pure cultures of L. monocytogenes after swab collection of adhered cells, which were then enumerated on PALCAM agar plates and visualized by scanning electron microscopy. Formation of a biofilm was recorded when the number of adhered cells was at least 10(3) CFU/cm2. When L. monocytogenes was cocultured with E. faecium bac-, the number of adhered L. monocytogenes cells was 2.5 log lower (P = 0.002) when initially compared with the control culture, but after 6 h of incubation a biofilm was again detected. However, in coculture on stainless steel coupons, E. faecium bac+ inhibited L. monocytogenes adherence and did not allow biofilm formation for up to 48 h (P < 0.001). In the presence of nisin or after treatment with peroxyacetic acid, bacterial growth was reduced (P < 0.001) up to 4.6 and 5.6 log CFU/cm2, respectively, when compared with L. monocytogenes cultures on untreated coupons. However, after these treatments, cells were still present, and after 24 h of incubation, a renewed biofilm was detected in L. monocytogenes cultures treated with nisin. Although all tested conditions reduced L. monocytogenes growth to some extent, only coculture with E. faecium bac+ efficiently reduced biofilm formation, suggesting a potential control strategy for this pathogen.
Assuntos
Biofilmes/crescimento & desenvolvimento , Técnicas de Cocultura/métodos , Desinfetantes/farmacologia , Enterococcus faecium/fisiologia , Contaminação de Equipamentos , Listeria monocytogenes , Aderência Bacteriana , Biofilmes/efeitos dos fármacos , Contagem de Colônia Microbiana , Enterococcus faecium/ultraestrutura , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Indústria de Processamento de Alimentos/instrumentação , Indústria de Processamento de Alimentos/métodos , Indústria de Processamento de Alimentos/normas , Humanos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/fisiologia , Listeria monocytogenes/ultraestrutura , Microscopia Eletrônica de Varredura , Nisina/farmacologia , Ácido Peracético/farmacologia , Aço Inoxidável , Propriedades de Superfície , Fatores de TempoRESUMO
Foi projetado um sistema de tratamento téermico por cascata, adaptando uma bandeja perfurada em uma autoclave Stock Pilot Rotor 90. Através de testes em bancada e em escala piloto foi desenvolvida uma equaçäo empírica, baseada na Lei de Potência para fluidos Newtonianos e na Lei de Poiseuile para escoamento laminar nos tubos circulares, correlacionando a vazäo de água com a área de escoamento, altura da coluna d'água e a espessura da chapa da bandeja.