O presente trabalho visa desenvolver métodos que permitam determinar as concentrações de tetraciclina, por Cromatografia Líquida de Alta Eficiência, no plasma e líquido sinovial, além de analisar as concentrações correspondentes em leite de gado leiteiro em lactação submetidos aos tratamentos intravenoso e intravenoso regional. Desta forma, objetivando determinar a depuração da tetracic1ina no organismo dos animais tratados, a concentração do fármaco no sítio de ação e a quantidade residual em leite, as amostras biológicas foram colhidas e quantificadas em diferentes tempos pré e pós-administração do fármaco. Os métodos analíticos validados apresentaram linearidade, limite de detecção, quantificação, exatidão, precisão e recuperação adequados à quantificação do antibiótico nas matrizes biológicas estudadas. As amostras de leite de animais tratados com o medicamento por via intravenosa regional, não apresentaram resíduos após 120h da administração do fármaco. O mesmo ocorreu plasma e líquido sinovial após 48 h. Através da administração via intravenosa do medicamento foram observados resíduos no leite em todos os tempos avaliados, ao passo que no plasma e líquido sinovial, a presença do princípio ativo não foi detectada após 72 horas pós-tratamento. / The purpose of the present work is to develop methods which allow the determination of tetracycline by High Pressure Liquid Chromatography in serum, synovial fluid, as well as analyze the corresponding milk concentrations in milk cows subjected to intravenous and regional intravenous treatment. Therefore, aiming to determine the clearance of tetracycline in the body of the treated animals, the concentration of the active principle in the action site and the residual quantity in milk, biological matrices were collected at different times. The validated analytical methods depicted suitable linearity, detection and quantification limits, accuracy, precision and recovery, allowing the quantification of the antibiotic in the studied biological matrices. In relation to the milk samples from animals treated with the drug by regional intravenous via, they did not present residues of tetracycline after 120 h post-administration. The values were also null for both serum and synovial fluid after 48 h. Through regional intravenous drug administration, milk residues were observed in all the evaluated times whereas for serum and synovial fluid, the presence of the active principle was not detected after 72h post-treatment.

Os antimicrobianos são amplamente utilizados no tratamento e prevenção de doenças do gado leiteiro. A ocorrência de resíduos de gentamicina, resultante principalmente do tratamento da mastite bovina é uma das principais causas o aparecimento de resíduos no leite. Neste estudo utilizando como técnica LC/MS-MS, foram analisadas 48 amostras de leite adquiridas em estabelecimentos comerciais, apenas uma apresentou resíduos de gentamicina no valor de 0, 112 ug/mL, superior ao LMR de 100 µg/ml estabelecido pela União Européia (UE), já para o leite in natura, das 55 amostras analisadas, quatro amostras foram positivas apresentando os valores 0,155 ug/mL, 0,192 ug/mL, 0,130 ug/ml e 0,167 ug/mL, todos acima do LMR estabelecido pela União Européia (UE). O método apresentou limite de quantificação de e 0,1 ng/mL, linearidade de 0,1-1500 ng/mL e coeficientes de determinação de 0,992557, recuperação de 91,5 % e com precisão e exatidão adequadas. Conhecer a dimensão da exposição da população a esses compostos é de fundamental importância para promover as ações de controle visando à proteção do consumidor. Desta forma as políticas de inspeção e qualidade do leite criadas pelo governo devem ser aplicadas e servir de garantia para o consumo seguro deste alimento pela população. / The antibiotics are widely used to treat and preventions diseases for dairy cattle. The occurrence of residues of gentamicin, resulting mainly from treatment of bovine mastitis are a major cause the appearance of residues in milk. In this study using the technique LC/MS-MS, were analyzed 48 samples of milk purchased in shops, only one sample present residues of gentamicin showing the value 0,112 ug/ml, exceeding the MRLs of µg/ml established by the European Union (EU) already for milk in nature, from 55 samples, four samples were positive showing the values 0,155 ug/mL, 0,192 ug/mL, 0,130 ug/ml and 0,167 ug/mL, All above the MRLs set by the European Union (EU). The method presented limit of quantification, and 0.1 ng/mL, linearity of 0,1-1500 ng/mL and coefficients of determination of 0.992557, recovery of 91.5% and with precision and accuracy appropriate. know the size of population\'s exposure to these compounds is of fundamental importance to promote measures to control aimed at protecting the consumer. Thus the politics of inspection and quality of milk created by the government should be implemented and serve as a guarantee for the safe consumption of food by the population.

Peanuts contribute significantly to food security in western Kenya due to their high nutritional value and cash crop potential. However, the crop is highly susceptible to aflatoxin contamination. Yet little information is available on the extent of contamination in the region. This study explores the level and extent of contamination of peanuts by aflatoxins, Aspergillus section Flavi, Rhizopus and Penicillium spp. in western Kenya. A survey of 769 households was carried out in the Busia and Homa bay districts of Kenya. Information on peanut pre- and post-harvest practices was collected through person-to-person interviews. Aflatoxin levels of samples collected from each household were determined by indirect competitive ELISA method. Isolation of Aspergillus section Flavi, Penicillium and Rhizopus spp. was done on Modified Dichloran Rose Bengal (MDRB) agar, while identification of specific fungal species was done on Czapek yeast extract agar (CYA). Screening isolates of A. flavus and A. parasiticus for aflatoxin production was done in high sucrose yeast extract (YES) liquid medium, and the aflatoxin types identified on TLC plates, using analytical grades of aflatoxin B1, B2, G1 and G2 as reference standards. Common household preparation techniques (roasting, making peanut paste and boiling peanuts) were evaluated for effectiveness in reducing aflatoxin levels in peanuts. The boiling procedure was modified to test the effect of magadi (locally available salt used mainly to soften legumes, vegetables or maize while cooking), ammonium persulphate and sodium hypochlorite during soaking. Magadi, sodium bicarbonate and locally prepared ash was subsequently used to boil the nuts after soaking. Aflatoxin levels ranged from zero to 7525 ìg/kg. Most samples were safe to consume, based on the European Union and Kenya Bureau of Standards tolerance levels, with 63.7 per cent of all samples having undetectable levels, and only 7.54 per cent being contaminated based on KEBS standards. Peanuts from the Busia district, which has more of Lower Midland 1 (mean annual rainfall of 1600-1800 mm) and Lower Midland 2 (mean annual rainfall of 1300-1700 mm) agro-ecological zones had significantly (÷2=14.172; P=0.0002) higher levels of aflatoxin compared to the Homa bay district, that has more of the drier Lower Midland 3 agroecological zone (mean annual rainfall of 900-1500mm). Improved cultivars had significantly (÷2=9.748; P=0.0018) lower levels of aflatoxin compared to local cultivars. Over 60 per cent of all samples had A. flavus S-strain, A. flavus L-strain and A. niger. A. flavus S-strain was positively correlated with aflatoxin levels. As expected, grading of peanuts post-harvest significantly reduced the incidence of A. flavus S- and L-strains, while peanuts collected from farmers who belonged to producer marketing groups had a significantly lower incidence of A. flavus S- and L-strains, A. niger and Rhizopus spp. The incidence of A. flavus L-strain, A. niger and Rhizopus spp. was significantly higher in local landraces compared to the improved cultivars. Over 60 per cent of isolates produced Aflatoxin B1. Intermediate processes such as sorting and dehusking led to a significant decline in levels of aflatoxin. Soaking peanuts in water, magadi, NaOCl and ammonium persulphate significantly reduced aflatoxin levels by 27.7, 18.4, 18.3 and 1.6 per cent respectively; while boiling the peanuts in magadi, local ash, baking powder and water reduced aflatoxin levels by 43.8, 41.8, 28.9 and 11.7 per cent respectively. Using magadi during boiling increased the acceptability of the boiled peanuts while reducing the aflatoxin levels. The impact of aflatoxin levels in peanuts studied in this research is within safe limits except a few samples, and therefore aflatoxin contamination of peanuts at household level is not a serious threat. Contamination by aflatoxin and post-harvest fungi can be reduced by focusing on improved control strategies for wetter and more humid zones such as planting improved peanut cultivars and controlling pre-harvest pest damage. Conventional household peanut preparation techniques should be explored as possible aflatoxin management strategies in Kenya. The aflatoxin binding properties of locally available salts such as magadi and locally prepared ash should be further investigated. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Thesis (MSc Food Sc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The agricultural sector of South Africa is currently facing a serious water crisis. The decreased availability of water as a result of climate change and the constantly growing population has left many farmers increasingly dependant on surface water as primary source of irrigation. Urbanisation along with out-dated and insufficient wastewater treatment works have all contributed to polluting large volumes of these resources. Consequently, many farmers have been forced to use irrigation water, not only of poor quality, but often water which has been polluted with untreated sewage. As a result, this project aimed at investigating the link between the quality of irrigation water and the impact on the safety of fresh produce. A base-line of the microbial load at three sites along the Plankenburg and Eerste Rivers was established using standard microbial methods for the detection of indicator organisms such as total and faecal coliforms, Escherichia coli and Enterococci as well as potential pathogens that included Salmonella, Listeria, Staphylococcus, endosporeformers and aerobic colony counts. Chemical parameters such as pH, alkalinity, conductivity and chemical oxygen demand (COD) were also monitored, but were not correlated to microbial pollution levels in the rivers. High faecal coliform and E. coli concentrations, ranging from 310 to 7 x 106 cfu.100 mL-1 and 230 to 7 x 106 cfu.100 mL-1, respectively, were detected. The recommended irrigation water guidelines of ≤1 000 (WHO, 1989) and ≤4 000 cfu.100 mL-1 (DWAF, 2008) for faecal coliforms and E. coli were exceeded, indicating faecal pollution and thus a high health risk. This health risk was confirmed when potential pathogens such as Aerococcus viridans, Klebsiella, Listeria monocytogenes and Salmonella typhimurium were detected at all three sites. The carryover of organisms from rivers to produce (green beans and grapes) was investigated by comparing the microbial population of the Plankenburg and Eerste Rivers to the population recovered from irrigation water and the surface of fresh produce. Faecal coliforms, E. coli, Aerococcus viridans, Enterobacter aerogenes, Klebsiella, L. innocua, L. grayi, L. monocytogenes and Staphylococcus aureus were detected in all three sample types, indicating a similarity between the microbial populations found in the river, the irrigation water and produce. Thus, the transfer of potential pathogens from the rivers to produce is a strong possibility. The build-up of organisms on the surface of green beans as a result of multiple irrigations was also confirmed by an increase in faecal coliform concentrations from initial concentrations of none detected to 44 000 cfu.100 mL-1 over a 10 day irrigation period. Finally, microbial source-tracking techniques including multi-antibiotic resistance (MAR) profiling, and the API 20E classification system were used to determine genotypic and phenotypic characteristics of 92 faecal isolates (from irrigation water and produce) and 13 reference strains. Numerical classification systems was used to classify the 105 faecal isolates according to the degree of similarity between the genotypic and phenotypic characteristics of the 105 isolates. A high degree of similarity indicates a high probability that isolates originate from the same strain and therefore from the same source, thereby confirming the transfer of organisms Faecal isolates (93 and 98%, respectively) were found to be resistant to Vancomycin at both the 5 and 30 μg concentrations. The majority of isolates presented some resistance to Erythromycin (15 μg) and Ampicillin (25 μg), with 82% of isolates presenting an inhibition zone ≤4 mm. Isolates were sensitive towards Ciprofloxacin (1 and 5 μg), Ofloxacin (15 μg), Ceftriaxone (30 μg) and Cefotaxime (5 μg), which were able to inhibit the growth of 79.8, 93.3, 79.8, 88.5 and 71.2% of the isolates, respectively. The 13 medical reference strains all presented different genotypic and phenotypic characteristics and thereby indicated a high degree of variability between isolates from the same species. Finally, 35% of the isolates could be grouped together based on similar genotypic and phenotypic characteristics, therefore, more than a third of the faecal isolates obtained from the surface of the fresh produce was as a result of faecal contaminants in the irrigation water. It could therefore be concluded that a health risk is associated with the water from the Plankenburg and to a lesser extent, Eerste River when used as source of irrigation, thereby risking the transfer of potentially harmful organisms, present in the rivers as result of faecal pollution, to the surface of fresh produce. / AFRIKAANSE OPSOMMING: Suid-Afrika stuur tans af op 'n dreigende water krisis. Klimaatsverandering tesame met 'n spoedig groeiende bevolking het gelei tot 'n aansienlike vermindering in die land se varswaterbronne terwyl veranderende reënvalpatrone daartoe bygedra het dat talle boere al hoe meer afhanklik geword het van oppervlakvarswaterbronne as hul hoof-besproeïngsbron. Verstedeliking, armoede asook verouderde en onvoldoende infrastrukture het egter bygedra tot die besoedeling van baie van hierdie oppervlakvarswaterbronne. Gevolglik is meeste boere genoodsaak om klaar te kom met besproeïngswater van, nie net onaanvaarbare mikrobiese kwaliteit nie, maar dikwels water wat gekontamineer is met onbehandelde riool. Hierdie studie was gevolglik daarop gemik om die impak van die mikrobiologiese kwaliteit van besproeïngswater op die veiligheid van vars groente en vrugte te bepaal. Standaard mikrobiologiese metodes vir die bepaling van indikator organismes soos totale en fekale kolivorms, E. coli en enterococci asook potensiële patogene wat Salmonella, Listeria en Staphylococcus insluit, was gebruik om die mikrobiese lading by drie verskillende punte (P1, P2 en P3) in die Plankenburg en Eerste Rivier te bepaal. Chemiese parameters soos pH, alkaliniteit, konduktiwiteit en Chemiese Suurstof Behoefte was ook bepaal maar geen korrelasie kon tussen hierdie eienskappe en die mikrobiese besoedelingsvlakke getref word nie. Hoë konsentrasies fekale kolivorms en E. coli wat onderskeidelik vanaf 3.1 x 102 tot 7 x 106 kve.100 mL-1 en 2.3 x 102 tot 7 x 106 kve.100 mL-1 gestrek het en gereeld die voorgeskrewe riglyne van onderskeidelik ≤1 000 (WHO, 1989) en ≤4 000 kve.100 mL-1 (DWAF, 2008) oorskry het, was by al drie punte gevind. Hierdie resultate het gedui op fekale besoedeling wat gevolglik met 'n hoë gesondheidsrisiko geassosieer kon word. Hierdie risiko was bevestig deur die teenwoordigheid van talle potensiële patogene, soos Aerococcus viridans, Klebsiella, Listeria monocytogenes en Salmonella typhimurium, wat vanaf al drie punte geïsoleer was. Die oordrag van organismes vanaf die besoedelde riviere na vars vrugte en groente (groen bone en druiwe) was bepaal deur die mikrobiese lading in die Plankenburg en Eerste Rivier te vergelyk met dié verkry vanuit die besproeïngswater en vanaf groen bone wat besproei was met hierdie water. Fekale kolivorms, E. coli, Aerococcus viridans, Enterobacter aerogenes, Klebsiella, L. innocua, L. grayi, L. monocytogenes en Staphylococcus aureus was vanaf al drie die monster tipes geïsoleer. Hierdie resultate het gedui op eenderse mikrobiese populasies in al drie bronne en het daarom die moontlike oordrag van patogene bevestig. Die opbou van organismes as gevolg van veelvuldige besproeïngsessies aan die oppervlak van groen bone was bevestig deur die toename in fekale kolivorm konsentrasie vanaf 'n begin telling van nul tot 'n maksimum konsentrasie van 44 000 kve.100 mL-1. Laastens was mikrobiologiese bron naspeurbaarheidstegnieke soos multi-antibiotika weerstandbiedende profiele en die API 20E klassifikasie sisteem gebruik om individuele genotipe en fenotipe profiele van die 105 fekale isolate saam te stel. Numeriese klassifikasie sisteme was gebruik om die isolate op grond van ooreenkomste tussen hul individuele fenotipiese en genotipiese karaktereienskappe te groeppeer. 'n Hoë mate van ooreenkomstigheid sal dan daarop dui dat isolate van dieselfde besoedlingsbron afkomstig is en gevolglik die oordrag van organismes vanaf besproeïngswater na vrugte en groente bevestig. Onderskeidelik 93 en 98% van die fekale isolate het daarop gedui om weerstandbiedend te wees teen beide 5 en 30 μg Vancomycin. Die meerderheid isolate (82%) het ook 'n mate van weerstand teenoor Erythromycin (15 μg) en Ampicillin (25 μg) getoon met inhibisie sones ≤4 mm. Isolate was ook sensitief teenoor Ciprofloxacin (1 en 5 μg), Ofloxacin (15 μg), Ceftriaxone (30 μg) en Cefotaxime (5 μg). Hierdie antibiotikums was in staat om die groei van onderskeidelik 79.8, 93.3, 79.8, 88.5 en 71.2 % van die isolate te inhibeer. Alhoewel resultate 'n hoë mate van variasie tussen isolate van dieselfde spesie getoon het was dit nogtans moontlik om 35% van die isolate saam te groeppeer op grond van ooreenstemmende genotipe en fenotipe profiele. Meer as 'n derde van die fekale isolate wat vanaf die oppervlakte van die groente en vrugte geïsoleer was, was afkomstig vanaf fekale besmetting in die besproeïngswater. Die oordrag van potensieël patogene organismes vanaf besoedelde riviere na vars vrugte en groente tydens besproeïng was sodoende bevestig. 'n Hoë gesondheidsrisiko was gevolglik gekoppel aan die gebruik van water vanaf die Plankenburg Rivier, en in 'n minder mate die Eerste Rivier, as bron van besproeïngswater. / Water Research Commission / National Research Foundation

Norovirus (NoV) is a significant cause of gastroenteritis globally, and the consumption of oysters is frequently linked to outbreaks. Depuration is the principle means employed to reduce levels of potentially harmful agents or toxins in shellfish. The aim of this thesis is to construct mathematical models which can describe the depuration dynamics of water-borne pathogens, and specifically examine the dynamics of NoV during depuration for a population shellfish. Legislation is currently under consideration within the EU by the Directorate-General for Health and Consumers (DG SANCO) to limit the maximum level of NoV that consumers are exposed to via this route. Therefore it is important to the utility of the thesis that any models constructed should incorporate control measures which could be used to implement minimum NoV levels. Doing so allowed calculation of minimum depuration times that would be required to adhere to the control measures incorporated into the models. In addition to modelling the impact on pathogens during the depuration, we wished to gain some insight into how the variability, and not just the mean levels, of water-borne pathogens can be as important with respect to the length of depuration required to minimise any food safety risks to the consumer. This proved difficult in the absence of any data sets that can be used to calculate variability measures, as little data is currently available to inform these values for NoV. However, our modelling techniques were able to calculate an upper limit on the variability of water-borne pathogens that can be well approximated by lognormal distributions. Finally we construct a model which provided linkage between the depuration process and the accretion of pathogens by shellfish while still within farming waters. This model proposed that the pulses of untreated waste waters released by sewage treatment works due to high levels of rainfall would be transmitted into shellfish whilst filter-feeding.

Phthalate esters (PEs) belong to a class of organic compounds used as plasticisers in plastic materials such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene terephthalate (PET) and so on, including those used in the food packaging industry. Phthalate plasticisers are not chemically bound to plastic materials and hence, migrate into items such as foodstuffs they house. The study aimed at investigating the prevalence of selected phthalate esters from plastic wrappers into food as well as the presence of food and/or pathogenic microorganisms. Plastic-wrapped cheese, vienna sausages and polony samples purchased from commercial stores in the four regions of Pretoria (Tswane), South Africa, were analysed for the presence of plasticisers; di-2-ethylhexyl adipate (DEHA), di-n-butyl phthalate (DnBP), benzyl-butyl phthalate (BBP), di-butyl phthalate (DBP) and dimethyl phthalate (DMP). Soxhlet extraction using hexane with florisil column cleanup was carried out. Analysis of PEs was by Gas Chromatography-Flame Ionization Detection (GC-FID). Microbiological investigations were performed using standard methods. The concentrations of PEs detected in food samples ranged from below detection limit (bdl) to 4.7003 μg/kg. However, DBP, DMP and BBP were predominantly present with more PEs detected in cheese compared to polony and vienna. In polony samples, DBP levels ranged from 0.0412 to 0.611μg/kg, in cheese, ranged from 0.049 to 0.256 μg/kg and in vienna DBP ranged from 0.074 to 0.209 μg/kg. The phthalate DMP ranged from 0.072 to 4.700 μg/kg in cheese, 0.056 to 0.241 μg/kg in polony and 0.092 to 0.816 μg/kg in vienna. The DEHA detected in cheese and polony was 0.120 μg/kg and 0.075 μg/kg respectively and no DEHA was detected in vienna sausages. For microbiological analysis, the total microbial activity (TMA) ranged from 6.8 x 104 to 1.03 x 108 cfu/g; coliforms ranged from no growth to 2.62 x 106 cfu/g; yeast ranged from no growth to 1.49 x 107 cfu/g; and mould ranged from no growth to 9.2 x 104 cfu/g. The results revealed that microbial activity was high in each sample type but revealed the absence of pathogens. Results revealed incidences of PEs in foods wrapped or packaged in plastics, which gave cause for concern and showed the need for proper monitoring and inspection of the levels of organo-microbial entities in the South African food wrapped in plastic wrappers. / Environmental Sciences / M.Sc. (Environmental Science)

Escherichia coli O157:H7 est le sérotype le plus souvent incriminé lors de toxi-infection alimentaire par les E. coli entérohémorragiques (EHEC). Il peut être associé, dans les cas les plus graves, à des colites hémorragiques mortelles et au syndrome hémolytique et urémique (SHU), touchant essentiellement les jeunes enfants. Le vecteur alimentaire le plus courant lors de ces contaminations est le boeuf haché. L’étape primaire de la contamination bactérienne se situe lors de l'abattage où les bactéries peuvent être transférées de la peau à la carcasse. Une gaine conjonctive entoure les muscles, sa composition protéique, similaire à la matrice extracellulaire (ECM), pourrait jouer un rôle dans l'adhésion bactérienne. Dans un premier temps, l’étude de l'adhésion et de la colonisation des bactéries aux protéines majeures de l’ECM musculaire, a révélé une forte influence des conditions de croissances sur l’adhésion, l'adhésion étant maximale à 25°C et pH7, en particulier aux collagènes I et III. Chez les EHEC, diverses protéines de surfaces peuvent être potentiellement impliquées dans l’adhésion à l’ECM. Le rôle d'un autotransporteur, l'antigène 43 (Ag43), dans l'autoagrégation, l'adhésion et la formation de biofilm, a été établit chez E. coli O157:H7 EDL933. Par la suite, les interactions entre E. coli O157:H7 et la viande ont été étudiées sur deux muscles modèles de types métabolique et contractile opposés (Soleus oxidatif lent et EDL, glycolytique rapide), caractérisés par microspectroscopie de fluorescence UV couplée au rayonnement synchrotron. Les différents types de fibres musculaires ainsi que l’effet d’une anoxie prolongée simulant la maturation des viandes ont été discriminés par leurs réponses spectrales après une excitation à 275 nm. Un tropisme bactérien plus élevé pour le muscle soleus que pour le muscle EDL a été clairement observé. Bien qu'E. coli O157:H7 adhère de manière similaire aux différents types de fibres musculaires, l'adhésion des bactéries se fait essentiellement au niveau de l'ECM, mettant en évidence le rôle clé de l'ECM et du tissu conjonctif musculaire dans l’adhésion des E. coli O157:H7 à la viande. Ces travaux de recherche sur l’adhésion bactérienne aux muscles squelettiques aux niveaux moléculaires, cellulaires et tissulaires fournissent les premières connaissances sur la physiologie des EHEC lors de la contamination de la viande et constituent un pré-requis indispensable au développement de pratiques et de stratégies innovantes afin de réduire le risque de contamination des viandes. / Escherichia coli O157:H7 is the most prevalent serotype involved in foodborne infection by enterohemorrhagic E. coli (EHEC). It is associated with life-threatening hemorrhagic colitis and the hemolyticuremic syndrome (HUS), which essentially affect young children. The major food vector of EHEC contamination is ground beef. The primary bacterial contamination occurs during the slaughter, essentially at dehiding stage where bacteria can be transferred from hides to carcasses. The connective tissue surrounding the muscle, highly similar to extracellular matrix (ECM) could potentially be a support for bacterial adhesion. When investigating the adhesion and colonization to the main muscle fibrous ECM proteins, the great influence of growth conditions on subsequent bacterial attachment was shown. Maximal adhesion to ECM proteins occurred at 25°C and pH 7, especially to collagens I and III. In EHEC, various surface-exposed protein determinants can be expressed and potentially involved in ECM adhesion. Investigating the autoaggregation, bacterial adhesion and biofilm formation, the involvement of Antigen 43 (Ag43), an autotransporter protein, was demonstrated in E. coli O157:H7 EDL933. Then, the attachment of E. coli O157:H7 to the meat was determined on two different model muscles, with different contractile and metabolic characteristic (Soleus oxidative, slow and EDL glycolytic, fast), previously characterized by UV microspectroscopy coupled to synchrotron radiation fluorescence. The different of muscle fiber types and the effect of a prolonged anoxia simulating maturing meat were discriminated by their spectral responses after excitation at 275 nm. It clearly appeared that bacteria displayed differential tropism as function of the muscle types, higher for the Soleus than the EDL muscles. While E. coli O157:H7 adhered similarly to the different types of muscle fibers, bacterial adherence essentially occurred at the ECM, pinpointing the key role of connective tissue for E. coli O157:H7 adhesion to meat. This first comprehensive investigation of bacterial adhesion to skeletal muscles at molecular, cellular and tissue levels provides new insight in the physiology of the colonization of meat by EHEC and constitutes a prerequisite for the development of innovative practices and strategies to minimize the risk of meat contamination.

Enterobacter sakazakii é um bacilo Gram-negativo, pertencente à família Enterobacterieceae. Este microrganismo vem ganhando a atenção das autoridades de saúde pública ao redor do mundo, não tanto pela morbidade, que é baixa, mas pela elevada taxa de mortalidade que varia de 40-80%. O patógeno afeta principalmente recém-nascidos de baixo peso e bebês com até seis meses de idade. Em comum, estas crianças têm o fato de serem alimentadas com fórmula infantil desidratada, a base de leite. Em nosso país ainda não existem muitos estudos sobre a ocorrência deste patógeno em fórmulas infantis, nem no ambiente de preparo das mesmas. O objetivo deste trabalho foi avaliar as condições de produção de mamadeiras para recém-nascidos em maternidades da Grande São Paulo, além de determinar a população de E. sakazakii em fórmulas infantis desidratadas e reidratadas. A população de Enterobacteriaceae e a presença de E. sakazakii também foram avaliadas em amostras ambientais, de utensílios e mão de manipuladores. Avaliou se ainda o comportamento do patógeno em fórmula infantil reidratada simulando as condições de oferecimento aos bebês. Coletou-se amostras de três hospitais maternidades diferentes (A-escola/B-público/C-particular) e analisou-se a presença de E. sakazakii usando método ISO. Para fórmulas desidratadas e reidratadas usou-se a mesma metodologia e a técnica de número mais provável (NMP). A população de Enterobacteriaceae foi determinada usando-se PetrifilmTM 3M. E. sakazakii foi detectada em duas amostras do Hospital A (na sobra da mamadeira que voltou do berçário e de uma amostra da lata lacrada da fórmula infantil desidratada. A população nesta amostra foi de 0,03 NMP/100g.) No Hospital B, foi detectada em apenas uma amostra (na esponja de lavagem das mamadeiras contaminadas). No Hospital C, E. sakazakii não foi detectada nas amostras analisadas. Quanto à população de Enterobacteriaceae nos lactários, observou-se uma variação, sendo que as amostras colhidas no hospital C foram as que apresentaram populações mais elevadas. As cepas de E. sakazakii isoladas apresentaram comportamento similar àquele da cepa padrão, ocorrendo um aumento de 2 log na população do patógeno quando simulou-se as condições de serviço das fórmulas, via naso-gástrica, aos bebês nos berçários. / Enterobacter sakazakii is a bacillus belonging to the Enterobacteriaceae family. It is considered an opportunistic pathogen that has been gaining attention from health authorities all over the world. While morbidity associated with this bacterium is low, mortality rates can range from 40-80%. The pathogen affects mainly low-birth-weight neonates (first 28 days), but babies less than 6 month old are also at risk. Powdered infant formula has been incriminated as the possible source of the microorganism to the infected babies. ln Brazil, as in several other countries, there is scarce information regarding the incidence of E. sakazakii in powdered infant formula, in reconstituted formula, and in milk kitchens areas in hospitals. The objective of this study was to evaluated the presence of E. sakazakii in the environment, utensils, handlers, powdered and rehydrated infant formula from milk kitchens from different maternity wards in Sao Paulo, Brazil. Moreover, it was evaluated the behavior of the pathogen in rehydrated infant formula. Samples were collected from 3 hospitals maternities (A-school/B-public/C-particular) and analyzed for E. sakazakii using the ISO method. For formula (powdered or rehydrated) the MPN technique was used. Enterobacteriaceae population was determined using PetrifilmTM 3M. E. sakazakii was found in one unopened formula can collected from Hospital A (0,03 MPN/100g), although the pathogen could not be detected in other cans from the same lot. E. sakazakii was also found in leftovers from one nursing bottle from the same hospital and from one cleaning sponge from Hospital B. E. sakazakii was not detected in none of the samples from Hospital C. A variation in Enterobacteriaceae population in milk kitchens was observed. Samples collected in Hospital C presented the highest population. Isolated strains of E. sakazakii presented similar behavior to standard strains, When spiked in rehidrated infant formula. A 2 log increase in the population of the pathogen was observed when simulating the conditions of formula administration to the babies by naso-gastric tubing.

Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras. / A rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 7 pyrethroid insecticides (bifenthrin, cypermethrin, fenpropathrin, fenvalerate, permethrin, lambda-cyhalothrin and deltamethrin) in beans. Residues are extracted from beans with acetone and the partition realized according to the multi-residue method DFG-S19, replacing dichloromethane by ethyl acetate/cyclohexane (1+1) and cleaned up using gel-permeation with a Biobeads SX3 column and ethyl acetate/cyclohexane (1+1) as eluant. LC separation is performed on a LiChrospher 100 RP-18 column with acetonitrile/water (8+2) as mobile phase. The pesticides are detected at 212 nm. Recoveries of 7 pyrethroid insecticides from beans fortified at 0.010; 0.100; 1.000 mg/kg levels were 71-105 %. The particular differential of this method is the quantification limits, which were between 0.004-0.011 mg/kg, lower than most of the limits reported for LC methods described in the literature. The gas chromatographic (GC) with electron capture detection is more sensitive than LC, but the LC method facilitates the identification of the peaks. Analysis of pyrethroids by GC shows several peaks, but LC shows only one for most pyrethroids. The analysis by LC was a good alternative for determination pyrethroid residues in beans. During 2005 year, a total of 48 bean samples commercialized in Sao Paulo City were analyzed. No residues of pyrethroids pesticides were detected in the samples.