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1.
J Food Prot ; 86(9): 100132, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37468108

RESUMO

Tree nuts, a low-moisture food, are typically perceived as being a low risk for foodborne illness. In the past five decades, the consumption of tree nuts (dry, soaked, or as nut-based dairy analogs [NBDA]) has increased along with corresponding foodborne illness outbreaks and recalls associated with these products. We developed an online survey to assess tree nut handling practices of U.S. consumers, and to select study participants who have soaked tree nuts and/or made NBDA at home. We distributed our initial survey questions in October 2021 to a convenience sample (n = 12) to test for clarity and comprehension. In January 2022, participants (n = 981) who met the criteria completed the survey. The most popular soaked tree nuts were almonds (54%), followed by cashews (36%), walnuts (32%), and pistachios (22%). Participants soaked tree nuts for direct consumption (67%) and during the preparation of NBDA (80%). Participants soaked tree nuts under refrigerated conditions for 1-24 h (22%), on the countertop at room temperature (est. 65-75°F [18-24°C]) for 1-5 h (21%), or at room temperature for 12 h or more (6%); 16% used a hot or boiling water, short time treatment. Some participants added acid (28%) or salt (25%) to the soaking water. Among those participants who dried their tree nuts after soaking (63%), 89% reported drying at a temperature lower than 46°C (115°F). Some participants (34%) used their tree nuts to make fermented dairy analogs (e.g., "cheese" or "yogurt") by adding "probiotics" (56-86%) or a yogurt starter culture (37-99%), respectively, and then, most frequently, holding at or below 20°C (68°F) for 12 h or less (29%). The safety of many of these practices has not been adequately investigated, but the findings of this study will inform future risk assessment and risk modeling studies on tree nut food safety in home kitchen settings.


Assuntos
Juglans , Prunus dulcis , Humanos , Nozes , Medição de Risco , Temperatura
2.
J Food Prot ; 86(8): 100116, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37321452

RESUMO

The fruit and vegetable juice industry has shown a growing trend in minimally processed juices. A frequent technology used in the production of functional juices is cold pressure, which refers to the application of high pressure processing (HPP) at low temperatures to inactivate foodborne pathogens. HPP juice manufacturers are required to demonstrate a 5-log reduction of the pertinent microorganism to comply with FDA Juice HACCP. However, there is no consensus on validation study approaches for bacterial strain selection or their preparation. Individual bacterial strains were grown using three different growth conditions: neutral, cold-adapted, and acid-adapted. Approximately 6.0-7.0 log CFU/mL of the matrix-adapted bacterial strains were inoculated individually into buffered peptone water (BPW) at pH 3.50 ± 0.10 (HCl adjusted) and treated at sublethal pressures of 500 MPa for Escherichia coli O157:H7 and 200 MPa for Salmonella spp. and Listeria monocytogenes (180 s, 4°C). Analyses were conducted at 0, 24, and 48 h (4°C storage) post-HPP on nonselective media. E. coli O157:H7 exhibited greater barotolerance than Salmonella spp. and L. monocytogenes. In neutral growth conditions, E. coli O157:H7 strain TW14359 demonstrated the greatest resistance (2.94 ± 0.64 log reduction), and E. coli O157:H7 strain SEA13B88 was significantly more sensitive (P < 0.05). Salmonella isolates, neutral and acid-adapted, expressed similar barotolerance to one another. Cold-adapted S. Cubana and S. Montevideo showed greater resistance compared to other cold-adapted strains. Acid-adapted L. monocytogenes strain MAD328 had <1.00 ± 0.23 log reduction while acid-adapted L. monocytogenes strains CDC and Scott A were significantly more sensitive (P < 0.05) with reductions of 2.13 ± 0.48 and 3.43 ± 0.50 log CFU/mL, respectively. These results suggested, under the conditions tested, bacterial strain and preparation methods influence HPP efficacy and should be considered when conducting validation studies.


Assuntos
Escherichia coli O157 , Listeria monocytogenes , Contagem de Colônia Microbiana , Salmonella , Frutas , Microbiologia de Alimentos
3.
J Food Prot ; 85(11): 1538-1552, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35723555

RESUMO

ABSTRACT: This multi-institutional study assessed the efficacy of Enterococcus faecium NRRL B-2354 as a nonpathogenic Salmonella surrogate for thermal processing of nonfat dry milk powder, peanut butter, almond meal, wheat flour, ground black pepper, and date paste. Each product was analyzed by two laboratories (five independent laboratories total), with the lead laboratory inoculating (E. faecium or a five-strain Salmonella enterica serovar cocktail of Agona, Reading, Tennessee, Mbandaka, and Montevideo) and equilibrating the product to the target water activity before shipping. Both laboratories subjected samples to three isothermal treatments (between 65 and 100°C). A log-linear and Bigelow model was fit to survivor data via one-step regression. On the basis of D80°C values estimated from the combined model, E. faecium was more thermally resistant (P < 0.05) than Salmonella in nonfat dry milk powder (DEf-80°C, 100.2 ± 5.8 min; DSal-80°C, 28.9 ± 1.0 min), peanut butter (DEf-80°C, 133.5 ± 3.1 min; DSal-80°C, 57.6 ± 1.5 min), almond meal (DEf-80°C, 34.2 ± 0.4 min; DSal-80°C, 26.1 ± 0.2 min), ground black pepper (DEf-80°C, 3.2 ± 0.8 min; DSal-80°C, 1.5 ± 0.1 min), and date paste (DEf-80°C, 1.5 ± 0.0 min; DSal-80°C, 0.5 ± 0.0 min). Although the combined laboratory D80°C for E. faecium was lower (P < 0.05) than for Salmonella in wheat flour (DEf-80°C, 9.4 ± 0.1 min; DSal-80°C, 10.1 ± 0.2 min), the difference was ∼7%. The zT values for Salmonella in all products and for E. faecium in milk powder, almond meal, and date paste were not different (P > 0.05) between laboratories. Therefore, this study demonstrated the impact of standardized methodologies on repeatability of microbial inactivation results. Overall, E. faecium NRRL B-2354 was more thermally resistant than Salmonella, which provides support for utilizing E. faecium as a surrogate for validating thermal processing of multiple low-moisture products. However, product composition should always be considered before making that decision.


Assuntos
Enterococcus faecium , Prunus dulcis , Contagem de Colônia Microbiana , Farinha , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Temperatura Alta , Pós , Salmonella/fisiologia , Triticum , Água/análise
4.
J Food Prot ; 85(2): 231-237, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34614182

RESUMO

ABSTRACT: Salmonella contamination in a dry processing facility frequently requires removal methods that are nonaqueous. Removal of pathogens from food processing systems with a purge of uncontaminated dry food materials has been proposed; however, little is known with respect to efficacy. In this study, survival of Salmonella on inert contact surfaces and transfer of Salmonella from inert contact surfaces to low-moisture foods were evaluated. Six stainless steel and polymeric food contact material types, in bead form, were contaminated at 11 log CFU/mL and then stored at two temperatures, 25 and 4°C, for 6 months. Simultaneously, three dry food materials or ingredients were used to remove Salmonella from contaminated beads. Wheat flour, cornmeal, and NaCl (1 g each) were mechanically mixed with 3 beads of each material type. The rate of microbial transfer from contaminated beads to food materials was measured. Further experimentation using multiple transfers was applied on two representative beads types, 316 stainless steel and polypropylene, representing common surface contact materials used in processing equipment. Survival of Salmonella on beads depended on storage temperature, with longer survival (P < 0.05) at 4°C than at 25°C, but survival was not influenced by type of bead material. Transfer of Salmonella from stainless steel beads to flour was significantly greater (P < 0.05) than from plastic. Transfer rates from stainless steel to wheat flour, cornmeal, and NaCl were measured as -0.5713, -0.2592, and -1.4221 log CFU of Salmonella removed per cm2 per g of clean material used. Transfer rates from polypropylene to whole wheat flour, cornmeal, and NaCl were more than 10-fold lower at -0.0156, -0.0148, and -0.0129 log CFU of Salmonella removed per cm2 per g of clean material used. These results indicate that although material type may not influence Salmonella survival during storage, Salmonella is more easily removed from stainless steel than polypropylene.


Assuntos
Farinha , Cloreto de Sódio , Aderência Bacteriana , Contagem de Colônia Microbiana , Manipulação de Alimentos , Microbiologia de Alimentos , Salmonella , Cloreto de Sódio/farmacologia , Aço Inoxidável , Triticum
5.
J Food Prot ; 84(11): 1990-2001, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34189582

RESUMO

ABSTRACT: The use of baking ovens as a microbial kill step should be validated based on results of thermal inactivation models. Although traditional isothermal models may not be appropriate for these dynamic processes, they are being used by the food industry. Previous research indicates that the impact of additional process conditions, such as humidity, should be considered when validating thermal processes for the control of microbial hazards in low-moisture foods. In this study, the predictive performance of traditional and modified thermal inactivation kinetic models accounting for process humidity were assessed for predicting inactivation of Enterococcus faecium NRRL B-2354 in a multi-ingredient composite food during baking. Ingredients (milk powder, protein powder, peanut butter, and whole wheat flour) were individually inoculated to achieve ∼6 log CFU/g, equilibrated to a water activity of 0.25, and then mixed to form a cookie dough. An isothermal inactivation study was conducted for the dough to obtain traditional D- and z-values (n = 63). In a separate experiment, cookies were baked under four dynamic heating conditions: 135°C, high humidity; 135°C, low humidity; 150°C, high humidity; and 150°C, low humidity. Process humidity measurements; time-temperature profiles for the product core, surface, and bulk air; and microbial survivor ratios were collected for the four conditions at six residence times (n = 144). The traditional isothermal model had a high root mean square error (RMSE) of 856.51 log CFU/g, significantly overpredicting bacterial inactivation during the process. The modified model accounting for the dynamic time-temperature profile and process humidity data was a better predictor with an RMSE of 0.55 log CFU/g. These results indicate the importance of accounting for additional process parameters in baking inactivation models and that model performance can be improved by utilizing model parameters obtained directly from industrial-scale experimental data.


Assuntos
Enterococcus faecium , Contagem de Colônia Microbiana , Farinha , Manipulação de Alimentos , Microbiologia de Alimentos , Salmonella , Triticum
6.
J Food Prot ; 83(4): 609-614, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32221564

RESUMO

ABSTRACT: Isothermal inactivation experiments often are used to investigate the thermal resistance of pathogens, such as Salmonella, in foods; however, little is known about the reproducibility of such experimental methodologies. The objective of this study was to quantify the reproducibility of Salmonella isothermal resistance results via a six-laboratory comparison. Inoculation was performed at a single location and then distributed to each laboratory for isothermal analysis. Salmonella Agona 447967 was inoculated into oat flour, re-equilibrated to a water activity (aw) of 0.45, and then packaged and distributed to each laboratory. Before conducting the inactivation trials, each laboratory was required to verify the inoculated product's aw, enumerate Salmonella population levels, and verify that the isothermal treatment medium was at the target temperature (80°C). All laboratories were required to process at least three replications, collect at least six sample time points with three subsamples at each sampling point, enumerate survivors using an identical plating methodology and media, and verify that the temperature did not substantially change during isothermal treatment. The log-linear model was fit to the Salmonella survivor data, and the resultant D-values were statistically compared via Welch's t test (α = 0.05). Two significant differences in thermal inactivation kinetics were identified as potentially resulting from suspected methodology deviations. Two of the inoculated batches distributed for analysis yielded significantly lower D-values, which likely resulted from a deviation in the inoculation procedures. One laboratory yielded significantly lower D-values, which was likely the result of temperature deviations. Overall, excluding the D-values resulting from deviations, the inactivation results were reproducible, yielding D-values of 30.2 ± 3 min. These results indicate that isothermal inactivation results can be reproducible but that even minor methodology deviations can substantially affect measured Salmonella thermal resistance.


Assuntos
Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Temperatura Alta , Salmonella/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Reprodutibilidade dos Testes
7.
J Food Prot ; 83(2): 211-220, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31928357

RESUMO

ABSTRACT: One intrinsic characteristic of low-moisture foods that is frequently overlooked is pH. Although pH affects the survival of microorganisms in high-moisture foods, its influence in low-moisture foods with less available moisture has not been examined. Escherichia coli O157:H7, E. coli O121, Salmonella enterica Anatum, and S. enterica Agona were grown on solid media with and without added glucose, harvested, and then suspended in buffer at pH 4, 5, and 7 for 10 min. All cultures were spotted individually onto cellulose filters and dried in a biohazard cabinet (23 ± 2°C) overnight (24 ± 2 h) and then stored in a 25°C incubator at 33% relative humidity. Populations were examined at regular intervals up to 26 (E. coli) or 29 (Salmonella) days. Additional controls for pH consisted of cultures held in buffer at pH 4, 5, and 7 at 25°C for the same time periods as the desiccated cells. For all strains tested, pH had an effect on survival whether stored dried or in liquid buffer (P < 0.05). However, when grown on solid media, acid adaptation (grown with glucose) before acid treatment did not appear beneficial to Salmonella during desiccation. Instead, both acid-adapted Salmonella serovars appeared less resistant during drying than did non-acid-adapted cells. Once dried, the rates of decline for Salmonella were not significantly different for acid-adapted and nonadapted cells (P > 0.05), indicating similar persistence following desiccation. A reverse trend was observed for E. coli O121; acid adaptation on solid media improved survival during desiccation and subsequent storage at low pH (P < 0.05). E. coli O157:H7 survival was significantly lower than that of either Salmonella or E. coli O121 under all conditions tested. Results indicate that the response to desiccation and pH stress differs between the microorganisms and under different growth conditions.

8.
J Food Prot ; 82(8): 1308-1313, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31310172

RESUMO

Non-O157 Shiga toxin-producing Escherichia coli infections have recently been associated with wheat flour on two separate accounts in the United States and Canada. However, there is little information regarding the thermal resistance and longevity of non-O157 Shiga toxin-producing Escherichia coli during storage in low-moisture environments. The objectives of this study were to determine the thermal inactivation kinetics of E. coli O121 in wheat flour and to compare the thermal inactivation rates with those of other pathogens. Wheat flour, inoculated with E. coli O121, was equilibrated at 25°C to a water activity of 0.45 in a humidity-controlled conditioning chamber. Inoculated samples were treated isothermally at 70, 75, and 80°C, and posttreatment population survivor ratios were determined by plate counting. D- and z-values calculated with a log-linear model, were compared with those obtained in other studies. At 70, 75, and 80°C, the D-values for E. coli O121 were 18.16 ± 0.96, 6.47 ± 0.50, and 4.58 ± 0.40 min, respectively, and the z-value was 14.57 ± 2.21°C. Overall, E. coli O121 was observed to be slightly less thermally resistant than what has been previously reported for Salmonella Enteritidis PT30 in wheat flour as measured under the same conditions with the same methods.


Assuntos
Dessecação , Farinha , Microbiologia de Alimentos , Temperatura Alta , Escherichia coli Shiga Toxigênica , Canadá , Contagem de Colônia Microbiana , Farinha/microbiologia , Escherichia coli Shiga Toxigênica/isolamento & purificação , Triticum/microbiologia
9.
J Food Prot ; 81(9): 1411-1417, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30059253

RESUMO

Salmonella can survive in low-moisture, high-protein, and high-fat foods for several years. Despite nationwide outbreaks and recalls due to the presence of Salmonella in low-moisture foods, information on thermal inactivation of Salmonella in these products is limited. This project evaluated the impact of water activity (aw), temperature, and food composition on thermal inactivation of Salmonella enterica serovar Agona in defined high-protein and high-fat model food matrices. Each matrix was inoculated with Salmonella Agona and adjusted to obtain a target aw, ranging from 0.50 to 0.98. Samples were packed into aluminum test cells and heated (52 to 90°C) under isothermal conditions. Survival of Salmonella Agona was detected on tryptic soy agar with 0.6% yeast extract. Complex influences by food composition, aw, and temperature resulted in significantly different ( P < 0.05) thermal resistance of Salmonella for the conditions tested. It was estimated that the same point temperatures at which the D-values of the two matrices at each aw (0.63, 0.73, 0.81, and 0.90) were identical were 79.48, 71.28, 69.62, and 38.42°C, respectively. Above these temperatures, the D-values in high-protein matrices were larger than the D-values in high-fat matrices at each aw. Below these temperatures, the inverse relationship was observed. A correlation between temperature and aw existed on the basis of the level of fat or protein in the food, showing that these compositional factors must be accounted for when predicating thermal inactivation of Salmonella in foods.


Assuntos
Microbiologia de Alimentos , Temperatura Alta , Salmonella enterica , Água , Contagem de Colônia Microbiana , Salmonella , Salmonella enterica/crescimento & desenvolvimento , Água/análise
10.
J Food Prot ; 81(5): 815-826, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29648932

RESUMO

An increase in the number of foodborne outbreaks and recalls due to Salmonella in low-moisture foods has resulted in the need for the development and validation of process controls to ensure their microbiological safety. Furthermore, the Food Safety Modernization Act Preventive Controls for Human Food final rule requires food processors to validate their process controls to ensure food safety. The objective of this study was to develop a response surface model to predict Salmonella inactivation in oat flour, as affected by moisture, fat content, screw speed, and temperature. Oat flour was adjusted to different moisture (14 to 26% wet basis) and fat (5 to 15% [w/w]) contents and was then inoculated with a five-strain cocktail of Salmonella. Inoculated material was extruded through a single-screw extruder running at different screw speeds (75 to 225 rpm) and temperatures (65 to 85°C), without a die. Once steady-state conditions were attained, extruded samples were collected, cooled, and stored under refrigeration, and Salmonella survivors were enumerated. A split-plot central composite second-order response surface design was used, with the central point replicated six times. Temperature showed a significant ( P < 0.0005) positive effect on microbial reduction. Moisture content showed significant linear ( P = 0.0014) and quadratic ( P = 0.0005) effects, whereas higher fat content showed a significant ( P < 0.0001) protective effect on Salmonella destruction. The screw speed did not play a major role in inactivating Salmonella, but it had a significant ( P = 0.0004) interactive effect with temperature. Results indicated that a >5.5-log reduction was achieved in oat flour extruded at a temperature above 85°C at all moisture and fat contents evaluated at a screw speed of 150 rpm. The developed response surface model can be used to identify the extrusion process conditions to achieve a desired reduction of Salmonella based on the moisture and fat contents of the product.


Assuntos
Avena , Farinha/microbiologia , Salmonella/fisiologia , Manipulação de Alimentos/métodos , Humanos , Salmonella/isolamento & purificação , Temperatura
11.
J Food Prot ; 81(4): 520-527, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29513105

RESUMO

Ready-to-eat foods based on dried partially sprouted seeds have been associated with foodborne salmonellosis. Whereas research has focused on the potential for Salmonella initially present in or on seeds to grow and survive during fresh sprout production, little is known about the potential for growth and survival of Salmonella associated with seeds that have been partially sprouted and dried. The goal of this study was to determine the growth of Salmonella during soaking for partial germination of pumpkin, sunflower, and chia seeds and subsequent survival during drying and storage. Pumpkin, sunflower, and chia seeds were inoculated with a four-serotype Salmonella cocktail by the dry transfer method and were soaked in sterile water at 25 or 37°C for 24 h. During the soaking period, Salmonella exhibited growth rates of 0.37 ± 0.26, 0.27 ± 0.12, and 0.45 ± 0.19 log CFU/h at 25°C and 0.94 ± 0.44, 1.04 ± 0.84, and 0.73 ± 0.36 log CFU/h at 37°C for chia, pumpkin, and sunflower seeds, respectively. Soaked seeds were drained and dried at 25, 51, and 60°C. Drying resulted in >5 log CFU/g loss at both 51 and 60°C and ∼3 log CFU/g loss at 25°C on partially sprouted pumpkin and sunflower seeds. There was no decrease in Salmonella during drying of chia seeds at 25°C, and only drying at 60°C provided losses >5 log CFU/g. Dried seeds were stored at 37 and 45°C at 15 and 76% relative humidity (RH) levels. The combination of temperature and RH exerted a stronger effect than either factor alone, such that rates at which Salmonella decreased generally followed this order: 37°C at 15% RH < 45°C at 15% RH < 37°C at 76% RH < 45°C at 76% RH for all seeds tested. Rates differed based on seed type, with chia seeds and chia seed powder having the smallest rate of Salmonella decrease, followed by sunflower and pumpkin seeds. Drying at higher temperatures (50 and 61°C) or storing at elevated temperature and humidity (45°C and 76% RH) resulted in significantly different rates of Salmonella decrease.


Assuntos
Cucurbita , Helianthus , Salmonella , Sementes , Contagem de Colônia Microbiana , Dessecação , Microbiologia de Alimentos , Germinação , Temperatura Alta , Humanos , Salmonella/crescimento & desenvolvimento , Intoxicação Alimentar por Salmonella , Infecções por Salmonella , Sementes/microbiologia , Sorogrupo , Temperatura , Água
12.
J Food Prot ; 80(2): 338-344, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28221981

RESUMO

Inoculation of a food product for use in subsequent validation studies typically makes use of a high concentration cocktail of microorganisms suspended in aqueous media. However, this inoculation method may prove difficult particularly when the food product is a low-moisture food containing antimicrobial compounds, such as some dried spices. In this study, a dry transfer method for inoculation of clove powder, oregano leaves, ginger powder, and ground black pepper with a five-serovar cocktail of Salmonella was developed and compared with a traditional aqueous inoculation procedure. Spices were inoculated at three levels, 10, 8, and 6 log CFU/g, by using both an aqueous suspension of Salmonella and a dry transfer of Salmonella from previously inoculated silica beads. At the highest inoculation level, the dry transfer method resulted in a significantly higher microbial load (P < 0.05) for ground cloves and oregano, but not for ginger and ground black pepper. At the intermediate inoculation level, differences were apparent only for ginger and black pepper. Inoculation levels of 6 log CFU/g resulted in recoveries below detection limits for both methods of inoculation. Additional examination on the survival of Salmonella on silica beads after inoculation and in clove powder after dry transfer from silica beads showed linear rates of decline, with a rate of -0.011 log CFU/g/day for beads and -0.015 log CFU/g/day for clove powder. The results suggest that dry transfer of Salmonella via inoculated silica beads is a viable alternative when traditional aqueous inoculation is not feasible.


Assuntos
Contagem de Colônia Microbiana , Especiarias , Anti-Infecciosos , Microbiologia de Alimentos , Piper nigrum , Salmonella
13.
Am J Case Rep ; 18: 166-169, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-28196967

RESUMO

BACKGROUND Myocarditis, defined as inflammation of myocardial tissue of the heart, is an uncommon cardiac presentation and is due to a variety of causes. It affects 1% of the US population, 50% of which is caused by coxsackie B virus. Cardiac tissue is the prime target, and destruction of myocardium results in cardiac failure with fluid overload. CASE REPORT Our patient was a 57-year-old woman with fever, headache, neck pain, and generalized malaise. Her white blood cell count was 13×10³ cells/mm³. Interestingly, lumbar puncture ruled out meningitis. An echocardiogram to evaluate elevated troponin revealed an ejection fraction of 30% with severe left ventricular global hypokinesis without valvular vegetations consistent with new-onset systolic heart failure. Cardiac MRI showed a small pericardial effusion with bilateral pleural effusion. As she continued to be febrile, a viral panel was ordered, revealing coxsackie B4 antibody titer of 1: 640 (reference: >1: 32 indicates recent infection) with positive Epstein-Barr virus deoxyribonucleic acid by PCR, consistent with viral myocarditis. CONCLUSIONS Coxsackie B virus myocarditis is rarely recognized and reported by the general internist in clinical practice, so we would like present our experience with an interesting clinical presentation of the viral prodrome. An estimated 95% people in the US are infected with Epstein-Barr virus by adulthood, but it remains dormant in memory B lymphocytes. Recirculation of these B cells in lymphoid tissue stimulated by antigens, which in our case is coxsackie B virus; they differentiate into plasma cells, and the production of Z Epstein-Barr replication activator protein (ZEBRA) increases viral replication, thus explaining the positive EBV DNA measured by PCR.


Assuntos
Infecções por Coxsackievirus/complicações , Enterovirus Humano B/isolamento & purificação , Infecções por Vírus Epstein-Barr/complicações , Hepatite/diagnóstico , Hepatite/virologia , Herpesvirus Humano 4/isolamento & purificação , Miocardite/diagnóstico , Miocardite/virologia , Diagnóstico Diferencial , Ecocardiografia/métodos , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Imagem Cinética por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Sensibilidade e Especificidade
14.
J Food Sci ; 82(3): 738-743, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28192610

RESUMO

Little research exists on Salmonella inactivation during extrusion processing, yet many outbreaks associated with low water activity foods since 2006 were linked to extruded foods. The aim of this research was to study Salmonella inactivation during extrusion of a model cereal product. Oat flour was inoculated with Salmonella enterica serovar Agona, an outbreak strain isolated from puffed cereals, and processed using a single-screw extruder at a feed rate of 75 kg/h and a screw speed of 500 rpm. Extrudate samples were collected from the barrel outlet in sterile bags and immediately cooled in an ice-water bath. Populations were determined using standard plate count methods or a modified most probable number when populations were low. Reductions in population were determined and analyzed using a general linear model. The regression model obtained for the response surface tested was Log (NR /NO ) = 20.50 + 0.82T - 141.16aw - 0.0039T2 + 87.91aw2 (R2 = 0.69). The model showed significant (p < 0.05) linear and quadratic effects of aw and temperature and enabled an assessment of critical control parameters. Reductions of 0.67 ± 0.14 to 7.34 ± 0.02 log CFU/g were observed over ranges of aw (0.72 to 0.96) and temperature (65 to 100 °C) tested. Processing conditions above 82 °C and 0.89 aw achieved on average greater than a 5-log reduction of Salmonella. Results indicate that extrusion is an effective means for reducing Salmonella as most processes commonly employed to produce cereals and other low water activity foods exceed these parameters. Thus, contamination of an extruded food product would most likely occur postprocessing as a result of environmental contamination or through the addition of coatings and flavorings.


Assuntos
Avena , Grão Comestível/microbiologia , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Salmonella enterica/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Farinha , Contaminação de Alimentos/análise , Humanos , Salmonella enterica/isolamento & purificação , Temperatura , Água
15.
J Food Sci ; 79(12): E2441-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25393920

RESUMO

Spices, including black pepper, are a source of microbial contamination and have been linked to outbreaks of salmonellosis when added to products that undergo no further processing. Traditional thermal processing employed to reduce microbial contamination can lead to losses of heat-sensitive compounds. Thus, alternative processes such as atmospheric pressure plasma (APP) are desirable. The purpose of this research was to determine the efficacy of APP in the destruction of Salmonella inoculated on the surface of peppercorns. Secondarily, we examined the effect of storage on the subsequent inactivation of Salmonella on the surfaces of black peppercorns by APP. Black peppercorns inoculated with a cocktail of Salmonella enterica serotypes Oranienburg, Tennessee, Anatum, and Enteritidis were stored at 25 °C, 33% relative humidity (RH); 25 °C, 97% RH; and, 37 °C, 33% RH for 10 d and additionally at 25 °C, 33% RH for 1 and 30 d then treated with APP. Results showed that Salmonella populations decreased significantly (P < 0.05) with respect to the treatment time, but where not related to previous storage conditions (P > 0.05). Approximately a 4.5- to 5.5-log10 reduction in population was achieved after 60 to 80 s treatment. A combination of treatments, storage and 80 s of plasma, may achieve a total reduction on the order of 7-log10 CFU/g. These findings support the potential of APP to decontaminate Salmonella on the surfaces of black peppercorns and other dry foods and illustrate that a multiple hurdle approach may prove effective for achieving significant reductions of Salmonella in many low-moisture foods.


Assuntos
Contaminação de Alimentos/prevenção & controle , Piper nigrum/microbiologia , Salmonella enterica/isolamento & purificação , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Armazenamento de Alimentos , Pressão , Especiarias/microbiologia
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