Shiga toxin-producing
(STEC) is a zoonotic pathogen that cause food-borne diseases in humans. Cattle and derived foodstuffs play a known role as reservoir and vehicles, respectively. In Uruguay, ...information about the characteristics of circulating STEC in meat productive chain is scarce. The aim was to characterize STEC strains recovered from 800 bovine carcasses of different slaughterhouses.
To characterize STEC strains we use classical microbiological procedures, Whole Genome Sequencing (WGS) and FAO/WHO risk criteria.
We analyzed 39 STEC isolated from 20 establishments. They belonged to 21 different O-groups and 13 different H-types. Only one O157:H7 strain was characterized and the serotypes O130:H11(6), O174:H28(5), and O22:H8(5) prevailed. One strain showed resistance
to tetracycline and genes for doxycycline, sulfonamide, streptomycin and fosfomycin resistance were detected. Thirty-three strains (84.6%) carried the subtypes Stx2a, Stx2c, or Stx2d. The gene eae was detected only in two strains (O157:H7, O182:H25). The most prevalent virulence genes found were
(
= 38),
(
= 39),
(
= 39),
(
= 38), and
(
= 39). Within the set of STEC analyzed, the majority (81.5%) belonged to FAO/WHO's risk classification levels 4 and 5 (lower risk). Besides, we detected STEC serotypes O22:H8, O113:H21, O130:H11, and O174:H21 belonged to level risk 2 associate with diarrhea, hemorrhagic colitis or Hemolytic-Uremic Syndrome (HUS). The only O157:H7 strain analyzed belonged to ST11. Thirty-eight isolates belonged to the Clermont type B1, while the O157:H7 was classified as E.
The analyzed STEC showed high genomic diversity and harbor several genetic determinants associated with virulence, underlining the important role of WGS for a complete typing. In this set we did not detect non-O157 STEC previously isolated from local HUS cases. However, when interpreting this findings, the low number of isolates analyzed and some methodological limitations must be taken into account. Obtained data suggest that cattle constitute a local reservoir of non-O157 serotypes associated with severe diseases. Other studies are needed to assess the role of the local meat chain in the spread of STEC, especially those associated with severe diseases in humans.
This study on raw ground beef patties evaluated: resistance of STEC strains inoculated at 6 log CFU/g (O157:H7, O26, O45, O103, O111, O121, and O145) subjected to 350, 450 and 600 MPa, for 5 min at ...10 °C; effectiveness of pressure for initial loads (2, 3 and 4 log CFU/g) of O157:H7; and general impact of high hydrostatic pressure (HHP) on raw patties. For 600 MPa treatments and 6 log CFU/g load of STEC, ~5 log CFU/g reductions were obtained with all strains. For 450 MPa, differences in baroresistance among strains became evident. When inoculating O157:H7 at different loads, counts after 600 MPa fell below quantification limits, though virulence genes were detected for the two highest loads. Additionally, HHP reduced native aerobic microbiota to <1 log CFU/g and slightly affected a* and b* color values. Montecarlo simulation was used to estimate potential initial counts of STEC that allow compliance with existing regulatory limits after applying HHP, showing that absence of STEC studied can be achieved in 65 g of patties provided initial loads are ~2 log CFU/g. Finally, HHP treatments at 600 MPa and mild temperatures can be considered a valid non-thermal processing technology to achieve 5 log CFU/g reductions.
•STEC in ground beef patties have caused numerous foodborne disease outbreaks.•HHP processing reduces near 5-log CFU/g of studied STEC counts in raw patties.•Absence in 65g for STEC loads of 2-log CFU/g is obtained in raw beef patties by HHP.•600 MPa HHP contributes to reach FSO and, therefore, ALOP, for STEC in patties.•These study results can be used in a risk-based approach to manage STEC in beef.
The objectives of the present work were to assess the use of moderate doses of gamma irradiation (2 to 5kGy) and to reduce the risk of pathogen presence without altering the quality attributes of ...bovine trimmings and of patties made of irradiated trimmings. Microbiological indicators (coliforms, Pseudomonas spp and mesophilic aerobic counts), physicochemical indicators (pH, color and tiobarbituric acid) and sensory changes were evaluated during storage. 5 kGy irradiation doses slightly increased off flavors in patties. Two pathogenic markers (Listeria monocytogenes and Escherichia coli O157:H7) were inoculated at high or low loads to trimming samples which were subsequently irradiated and lethality curves were obtained. Provided that using irradiation doses ≤2.5kGy are used, reductions of 2logCFU/g of L. monocytogenes and 5logCFU/g of E. coli O157:H7 are expected. It seems reasonable to suppose that irradiation can be successfully employed to improve the safety of frozen trimmings when initial pathogenic bacteria burdens are not extremely high.
•Irradiation proved to be a valid alternative for processing bovine trimmings.•2logCFU/g of L. monocytogenes are reduced using irradiation doses up to 2.5kGy.•5logCFU/g of E. coli O157:H7 are reduced using irradiation doses up to 2.5kGy.•Irradiation doses of up to 5kGy did not affect L*, a* and b* values on beef patties.•There were no sensory differences between patties made of 1 or 30d aged irradiated trimmings.•5kGy dose increased off flavor intensity of patties made of 30d aged trimmings.
Este artigo indica algumas aproximações teóricas quanto às possibilidades e desafios para a consolidação de uma pedagogia universitária para a formação dos profissionais do magistério para atuar na ...Educação Básica. Metodologicamente, está vinculado à concepção dialética histórica, com aporte na técnica de Análise de Conteúdo (BARDIN, 2002). A pesquisa indica para as conquistas teórico-metodológicas no âmbito da produção de pesquisa sobre a pedagogia universitária no contexto da educação superior brasileira e para as dificuldades de superação das características da experiência histórica de pedagogia universitária no Brasil, configurando um cenário de disputa entre as conquistas pedagógicas atuais e a tradição técnico-profissionalizante, fragmentada e utilitária da educação superior.
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