The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
J Saldanalozano - One of the best experts on this subject based on the ideXlab platform.
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prevalence of salmonella in chorizo and its survival under different storage temperatures
Food Microbiology, 1999Co-Authors: Eduardo F. Escartin, A Hinojosapuga, A. Castillo, J SaldanalozanoAbstract:Abstract The prevalence of Salmonella in chorizo, a raw pork sausage, was studied in two locations in Mexico. Sixty samples were collected from butcher shops and retail markets in Guadalajara city, and another 80 samples were collected from butcher shops (40 samples) and grocery stores (40 samples) in Queretaro city. Samples obtained from butcher shops had been produced at the same butchery, whereas those obtained from grocery stores in Queretaro had been processed at national Meat Processing Plants. In Guadalajara, 88% of the samples tested positive to Salmonella . In Queretaro, 78% of the samples collected from butcher shops and 5% of the samples collected from grocery stores tested positive to Salmonella . The ability to isolate Salmonella from chorizo was affected by the method of analysis and was best achieved by preenrichment of 20 g of sample in buffered peptone water for 24 h, followed by enrichment in tetrathionate brilliant green and selenite cystine broths. The five most frequent serovars isolated were S. derby (26%), S. anatum (14%), S. infantis (14%), S. typhimurium (12%) and S. brandenburg (6%). Five selected samples that tested positive for Salmonella were selected for enumeration by most probable number (MPN) and subsequent survival studies during storage of chorizo at refrigeration (4–6°C) and at room temperature (18–22°C). Initial numbers of Salmonella varied from 900 to 0·04 MPN g −1 , and with the exception of the sample containing 900 Salmonella MPN g −1 , all other samples were cleared from this pathogen after 21 days of refrigeration or 5–10 days at room temperature. Salmonella contamination in chorizo can be prevented by improving the bacteriological quality and safety of the raw materials and by controlling the natural aging process of this product.
Peter M. Muriana - One of the best experts on this subject based on the ideXlab platform.
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Adherence characteristics of Listeria strains isolated from three ready-to-eat Meat Processing Plants.
Journal of food protection, 2009Co-Authors: Kalpana Kushwaha, Peter M. MurianaAbstract:Over 1,560 non–food contact surface swabs and raw Meat ingredient samples were collected from three ready-to-eat Meat Processing Plants (520 from each plant) from 1998 to 1999, resulting in the recovery of 259 isolates of Listeria obtained from postprocess areas including drains, floors, garbage bins, cart wheels, walls, equipment surfaces, tables, brooms, pallet jacks, hoses, ladders, and waste chutes. We further examined 246 of the 259 isolates for adherence phenotype and used PCR to identify those that were Listeria monocytogenes. Adherence was classified as weak, moderate, or strong depending on results obtained with all Listeria isolates by using a fluorescent microplate adherence assay. Among the 246 isolates, there were 61 weakly, 148 moderately, and 37 strongly adherent Listeria, of which 130 (53%) were found to be L. monocytogenes. Plants A and B provided similar recoveries of 39 (7.5%) and 43 (8.3%) Listeria-positive isolates, including 9 (23.1% of Listeria) and 41 (95.3% of Listeria) identified...
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microplate fluorescence assay for measurement of the ability of strains of listeria monocytogenes from Meat and Meat Processing Plants to adhere to abiotic surfaces
Applied and Environmental Microbiology, 2007Co-Authors: Rachel K Gamble, Peter M. MurianaAbstract:Listeria monocytogenes is a significant food-borne pathogen that is capable of adhering to and producing biofilms on Processing equipment, making it difficult to eliminate from Meat-Processing environments and allowing potential contamination of ready-to-eat (RTE) products. We devised a fluorescence-based microplate method for screening isolates of L. monocytogenes for the ability to adhere to abiotic surfaces. Strains of L. monocytogenes were incubated for 2 days at 30°C in 96-well microplates, and the plates were washed in a plate washer. The retained cells were incubated for 15 min at 25°C with 5,6-carboxyfluorescein diacetate and washed again, and then the fluorescence was read with a plate reader. Several enzymatic treatments (protease, lipase, and cellulase) were effective in releasing adherent cells from the microplates, and this process was used for quantitation on microbiological media. Strongly adherent strains of L. monocytogenes were identified that had 15,000-fold-higher levels of fluorescence and 100,000-fold-higher plate counts in attachment assays than weakly adherent strains. Strongly adherent strains of L. monocytogenes adhered equally well to four different substrates (glass, plastic, rubber, and stainless steel); showed high-level attachment on microplates at 10, 20, 30, and 40°C; and showed significant differences from weakly adherent strains when examined by scanning electron microscopy. A greater incidence of strong adherence was observed for strains isolated from RTE Meats than for those isolated from environmental surfaces. Analysis of surface adherence among Listeria isolates from Processing environments may provide a better understanding of the molecular mechanisms involved in attachment and suggest solutions to eliminate them from food-Processing environments.
Kendra K. Nightingale - One of the best experts on this subject based on the ideXlab platform.
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Molecular ecology of Listeria monocytogenes and other Listeria species in small and very small ready-to-eat Meat Processing Plants.
Journal of food protection, 2011Co-Authors: Shanna K. Williams, Sherry Roof, Elizabeth A. E. Boyle, Dennis E. Burson, Harshavardhan Thippareddi, Ifigenia Geornaras, John N. Sofos, Martin Wiedmann, Kendra K. NightingaleAbstract:A longitudinal study was conducted to track Listeria contamination patterns in ready-to-eat Meats from six small or very small Meat Processing Plants located in three states over 1 year. A total of 688 environmental sponge samples were collected from nonfood contact surfaces during bimonthly visits to each plant. Overall, L. monocytogenes was isolated from 42 (6.1%) environmental samples, and its prevalence ranged from 1.7 to 10.8% across different Plants. Listeria spp., other than L. monocytogenes, were isolated from 9.5% of samples overall, with the prevalence ranging from 1.5 to 18.3% across different Plants. The prevalence of L. monocytogenes correlated well with that of other Listeria spp. for some but not all Plants. One L. monocytogenes isolate representing each positive sample was characterized by molecular serotyping, EcoRI ribotyping, and pulsed-field gel electrophoresis typing. Seven sample sites tested positive for L. monocytogenes on more than one occasion, and the same ribotype was detected more than once at five of these sites. Partial sigB sequencing was used to speciate other Listeria spp. isolates and assign an allelic type to each isolate. Other Listeria spp. were isolated more than once from 14 sample sites, and the same sigB allelic type was recovered at least twice from seven of these sites. One plant was colonized by an atypical hemolytic L. innocua strain. Our findings indicate that small and very small Meat Processing Plants that produce ready-to-eat Meat products are characterized by a varied prevalence of Listeria, inconsistent correlation between contamination by L. monocytogenes and other Listeria spp., and a unique Listeria molecular ecology.
Hannu Korkeala - One of the best experts on this subject based on the ideXlab platform.
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Prevalence and genetic diversity of Listeria monocytogenes in vacuum-packaged ready-to-eat Meat products at retail markets in Latvia.
Journal of food protection, 2009Co-Authors: Aivars Bērziņš, Margarita Terentjeva, Hannu KorkealaAbstract:Nine groups of different retail ready-to-eat vacuum-packaged Meat products from 10 Baltic Meat Processing Plants were analyzed for presence and numbers of Listeria monocytogenes at the end of shelf life. A total of 38 (18%) of 211 samples tested positive for L. monocytogenes serotype 1/2a (88%) or 1/2c (12%). The prevalence of L. monocytogenes in cold-smoked, sliced, vacuum-packaged beef and pork products (42%) was significantly higher than in cooked, sliced, vacuum-packaged Meat products (0.8%) (P < 0.001). Enumeration of L. monocytogenes showed that 84% of the positive samples contained
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Factors associated with Listeria monocytogenes contamination of cold-smoked pork products produced in Latvia and Lithuania
International journal of food microbiology, 2006Co-Authors: A. Bērziņš, Ari Hörman, Janne Lundén, Hannu KorkealaAbstract:A total of 312 samples of sliced, vacuum packaged, cold-smoked pork from 15 Meat Processing Plants in Latvia and Lithuania, obtained over a 15-month period from 2003 until 2004, were analyzed for the presence of Listeria monocytogenes at the end of their shelf-life. Overall, 120 samples (38%) tested positive for L. monocytogenes. Despite the long storing period, the levels of L. monocytogenes in cold-smoked pork products were low. Manufacturing processes were studied at seven Meat Processing Plants. A new approach with a logistic multivariable regression model was applied to identify the main factors associated with L. monocytogenes contamination during the manufacturing of coldsmoked pork products. Brining by injection was a significant factor (odds ratio 10.66; Pb0.05) for contamination of product with L. monocytogenes. Moreover, long cold-smoking times (≥12 h) had a significant predictive value (odds ratio 24.38; Pb0.014) for a sample to test positive for L. monocytogenes. Pulsed-field gel electrophoresis results indicated that various sources of L. monocytogenes contamination existed over periods of time in several Meat Processing Plants. In two Meat Processing Plants, persistent L. monocytogenes strains belonging to serotypes 1/2a and 1/2c were found.
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persistent and nonpersistent listeria monocytogenes contamination in Meat and poultry Processing Plants
Journal of Food Protection, 2003Co-Authors: Janne Lundén, Tiina Autio, Annamaija Sjoberg, Hannu KorkealaAbstract:Contamination analysis of persistent and nonpersistent Listeria monocytogenes strains in three Meat Processing Plants and one poultry Processing plant were performed in order to identify factors predisposing to or sustaining persistent plant contamination. A total of 596 L. monocytogenes isolates were divided into 47 pulsed-field gel electrophoresis (PFGE) types by combining the restriction enzyme patterns of AscI (42 patterns) and ApaI (38 patterns). Persistent and nonpersistent strains were found in all Plants. Nonpersistent PFGE types were found mostly at one sampling site, with the Processing environment being the most common location, whereas the persistent strains were found at several sampling sites in most cases. The Processing machines were frequently contaminated with persistent L. monocytogenes PFGE types, and it was of concern that surfaces having direct contact with the products were contaminated. The role of the Processing machines in sustaining contamination and in contaminating the product...
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Ropy slime-producing lactic acid bacteria contamination at Meat Processing Plants.
International journal of food microbiology, 1992Co-Authors: Pia Mäkelä, Hannu Korkeala, Jorma J. LaineAbstract:At three Finnish Meat Processing Plants the Processing rooms, Meat trimmings and carcasses were examined for the presence of ropy slime-producing lactic acid bacteria. Bacterial isolates similar to ropy slime-producing lactobacilli strains able to produce ropy slime on Meat products, were recovered from the Processing rooms and Meat trimmings, indicating that these rooms and raw materials are a source of contamination for ropy bacteria. The ability to produce ropy slime would appear to be a common characteristic of lactobacilli, since altogether 10 different ropy lactobacilli groups were isolated in this study.
Eduardo F. Escartin - One of the best experts on this subject based on the ideXlab platform.
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prevalence of salmonella in chorizo and its survival under different storage temperatures
Food Microbiology, 1999Co-Authors: Eduardo F. Escartin, A Hinojosapuga, A. Castillo, J SaldanalozanoAbstract:Abstract The prevalence of Salmonella in chorizo, a raw pork sausage, was studied in two locations in Mexico. Sixty samples were collected from butcher shops and retail markets in Guadalajara city, and another 80 samples were collected from butcher shops (40 samples) and grocery stores (40 samples) in Queretaro city. Samples obtained from butcher shops had been produced at the same butchery, whereas those obtained from grocery stores in Queretaro had been processed at national Meat Processing Plants. In Guadalajara, 88% of the samples tested positive to Salmonella . In Queretaro, 78% of the samples collected from butcher shops and 5% of the samples collected from grocery stores tested positive to Salmonella . The ability to isolate Salmonella from chorizo was affected by the method of analysis and was best achieved by preenrichment of 20 g of sample in buffered peptone water for 24 h, followed by enrichment in tetrathionate brilliant green and selenite cystine broths. The five most frequent serovars isolated were S. derby (26%), S. anatum (14%), S. infantis (14%), S. typhimurium (12%) and S. brandenburg (6%). Five selected samples that tested positive for Salmonella were selected for enumeration by most probable number (MPN) and subsequent survival studies during storage of chorizo at refrigeration (4–6°C) and at room temperature (18–22°C). Initial numbers of Salmonella varied from 900 to 0·04 MPN g −1 , and with the exception of the sample containing 900 Salmonella MPN g −1 , all other samples were cleared from this pathogen after 21 days of refrigeration or 5–10 days at room temperature. Salmonella contamination in chorizo can be prevented by improving the bacteriological quality and safety of the raw materials and by controlling the natural aging process of this product.