scholarly journals Genetic Diversity of Stenocarpella maydis in the Major Corn Production Areas of the United States

Plant Disease ◽  
2017 ◽  
Vol 101 (12) ◽  
pp. 2020-2026 ◽  
Author(s):  
Martha P. Romero Luna ◽  
M. Catherine Aime ◽  
Martin I. Chilvers ◽  
Kiersten A. Wise
Keyword(s):  
United States ◽  
Genetic Diversity ◽  
Geographical Location ◽  
The United States ◽  
Most Probable Number ◽  
Ear Rot ◽  
Corn Production ◽  
Probable Number ◽  
Production Areas ◽  
Stenocarpella Maydis

The fungus Stenocarpella maydis (Berk.) B. Sutton, causal agent of Diplodia ear rot, is a prevalent corn (Zea mays L.) pathogen in the United States. Although S. maydis reduces grain quality, causes yield loss, and can produce mycotoxins in some countries, few studies have examined its biology and genetic diversity. We analyzed the genetic diversity of 174 S. maydis isolates sampled across the major corn production areas in the United States using nine different microsatellites. In all, 55 unique multilocus genotypes (MLG) were observed out of the 174 S. maydis isolates tested. After conducting a Bayesian clustering analysis by STRUCTURE, it was observed that the most probable number of genetic groups was two; however, no separation by their geographical location was identified. According to the minimum spanning network, the S. maydis population is linked across geographic regions of the United States but also contains private genotypes. Temporal diversity in the inoculum source was also observed at one location across 4 years. The haploid stage of S. maydis was confirmed and both mating type genes were amplified among selected isolates with unique MLG. We theorize that, although S. maydis is primarily an asexual fungus, sporadic cryptic recombination may occur, which could contribute to the genetic diversity observed in this study.

Occurrence of Stenocarpella macrospora Causing Ear Rot in Corn in the United States

2016 ◽  
Vol 17 (2) ◽  
pp. 152-154
Author(s):  
Martha P. Romero Luna ◽  
Carl A. Bradley ◽  
Heather M. Kelly ◽  
Kiersten A. Wise
Keyword(s):  
United States ◽  
South Africa ◽  
South America ◽  
The United States ◽  
Ear Rot ◽  
Stenocarpella Maydis ◽  
The U.S ◽  
Related Fungus

Diplodia ear rot of corn is primarily caused by the fungus Stenocarpella maydis in the United States. Stenocarpella macrospora is a closely related fungus present in the U.S. but primarily associated with Diplodia leaf streak. S. macrospora is recognized as a major ear rot pathogen in South America and South Africa, but has infrequently been associated with ear rot in the U.S. This brief presents the first reports of Diplodia ear rot in Illinois and Tennessee. This is also the first confirmation of S. macrospora causing ear rot in the U.S. in over 60 years. Accepted for publication 19 May 2016. Published 15 June 2016.

Prevalence and Level of Listeria monocytogenes in Ice Cream Linked to a Listeriosis Outbreak in the United States

2016 ◽  
Vol 79 (11) ◽  
pp. 1828-1832 ◽  
Author(s):  
YI CHEN ◽  
LAUREL S. BURALL ◽  
DUMITRU MACARISIN ◽  
RÉGIS POUILLOT ◽  
ERROL STRAIN ◽  
...  
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
Limit Of Detection ◽  
Geometric Mean ◽  
Ice Cream ◽  
The United States ◽  
Most Probable Number ◽  
Data Set ◽  
Probable Number ◽  
Susceptible Populations

ABSTRACT A most-probable-number (MPN) method was used to enumerate Listeria monocytogenes in 2,320 commercial ice cream scoops manufactured on a production line that was implicated in a 2015 listeriosis outbreak in the United States. The analyzed samples were collected from seven lots produced in November 2014, December 2014, January 2015, and March 2015. L. monocytogenes was detected in 99% (2,307 of 2,320) of the tested samples (lower limit of detection, 0.03 MPN/g), 92% of which were contaminated at <20 MPN/g. The levels of L. monocytogenes in these samples had a geometric mean per lot of 0.15 to 7.1 MPN/g. The prevalence and enumeration data from an unprecedented large number of naturally contaminated ice cream products linked to a listeriosis outbreak provided a unique data set for further understanding the risk associated with L. monocytogenes contamination for highly susceptible populations.

Prevalence of Salmonella in Cashews, Hazelnuts, Macadamia Nuts, Pecans, Pine Nuts, and Walnuts in the United States

2017 ◽  
Vol 80 (3) ◽  
pp. 459-466 ◽  
Author(s):  
Guodong Zhang ◽  
Lijun Hu ◽  
David Melka ◽  
Hua Wang ◽  
Anna Laasri ◽  
...  
Keyword(s):  
United States ◽  
Culture Method ◽  
The United States ◽  
Most Probable Number ◽  
Contamination Level ◽  
Probable Number ◽  
Tree Nuts ◽  
Prevalence Estimates ◽  
Macadamia Nuts ◽  
Small Chain

ABSTRACT Nuts have been identified as a vector for salmonellosis. The objective of this project was to estimate the prevalence and contamination level of Salmonella in raw tree nuts (cashews, pecans, hazelnuts, macadamia nuts, pine nuts, and walnuts) at retail markets in the United States. A total of 3,656 samples of six types of tree nuts were collected from different types of retail stores and markets nationwide between October 2014 and October 2015. These samples were analyzed using a modified version of the Salmonella culture method from the U.S. Food and Drug Administration's Bacteriological Analytical Manual. Of the 3,656 samples collected and tested, 32 were culturally confirmed as containing Salmonella. These isolates represented 25 serotypes. Salmonella was not detected in pecans and in-shell hazelnuts. Salmonella prevalence estimates (and 95% confidence intervals) in cashews, shelled hazelnuts, pine nuts, walnuts, and macadamia nuts were 0.55% [0.15, 1.40], 0.35% [0.04, 1.20], 0.48% [0.10, 1.40], 1.20% [0.53, 2.40], and 4.20% [2.40, 6.90], respectively. The rates of Salmonella isolation from major or big chain supermarkets, small chain supermarkets, discount, variety, or drug stores, and online were 0.64% [0.38, 1.00], 1.60% [0.80, 2.90], 0.00% [0.00, 2.40], and 13.64% [2.90, 35.00], respectively (Cochran-Mantel-Haenszel test: P = 0.02). The rates of Salmonella isolation for conventional and organic nuts were not significantly different. Of the samples containing Salmonella, 60.7% had levels less than 0.003 most probable number (MPN)/g. The highest contamination level observed was 0.092 MPN/g. The prevalence and levels of Salmonella in these tree nut samples were comparable to those previously reported for similar foods.

scholarly journals Salmonella enterica Burden in Harvest-Ready Cattle Populations from the Southern High Plains of the United States

2007 ◽  
Vol 74 (2) ◽  
pp. 345-351 ◽  
Author(s):  
David J. Kunze ◽  
Guy H. Loneragan ◽  
Tammy M. Platt ◽  
Mark F. Miller ◽  
Thomas E. Besser ◽  
...  
Keyword(s):  
United States ◽  
Salmonella Enterica ◽  
The United States ◽  
Most Probable Number ◽  
High Plains ◽  
Antimicrobial Drugs ◽  
Probable Number ◽  
At Risk Populations ◽  
High Level ◽  
Level Resistance

ABSTRACT Our objectives were to quantify the Salmonella enterica burdens in harvest-ready cattle and to identify specific at-risk populations of cattle most likely to harbor multiply resistant S. enterica. Hide swabs were collected in abattoirs from three cohorts of cattle (feedlot origin cattle that had achieved desirable harvest characteristics and dairy- and beef-type cows harvested because of poor productivity). Feces were collected from two cohorts housed in feedlots (cattle that had achieved desirable harvest characteristics and animals identified for salvage recovery because of poor productivity). Facilities were visited on four occasions over a 12-month period. Salmonella enterica isolates were recovered, and organisms were quantified using standard microbiological methodologies. Susceptibility to antimicrobial drugs and serotype were determined for one S. enterica isolate per sample. Salmonella enterica was recovered from 55.6% of 1,681 samples. The prevalences on hides and in feces were 69.6% and 30.3%, respectively. The concentrations of S. enterica organisms averaged (as determined by the most probable number technique) 1.82 log10/100 cm2 of hides and 0.75 log10/g of feces. None of the isolates recovered from cattle that had achieved desirable harvest characteristics were resistant to four or more drugs. For isolates recovered from animals with poor productivity characteristics, 6.5% were resistant to four or more drugs. Twenty-two serovars were identified, with the most common being Salmonella enterica serovar Anatum (25.5%), Salmonella enterica serovar Montevideo (22.2%), and Salmonella enterica serovar Cerro (12.5%). High-level resistance, i.e., resistance to four or more drugs, was clustered within a few relatively uncommon serovars. These results demonstrate that even though S. enterica isolates are readily recoverable from harvest-ready cattle, multiply resistant variants are rare and are associated with specific serovars in cattle harvested because of poor productivity characteristics.

Prevalence and Concentration of Salmonella on Raw, Shelled Peanuts in the United States

2018 ◽  
Vol 81 (11) ◽  
pp. 1755-1760 ◽  
Author(s):  
STEPHEN CALHOUN ◽  
LAURIE POST ◽  
BENJAMIN WARREN ◽  
STERLING THOMPSON ◽  
ANN ROGERS BONTEMPO
Keyword(s):  
United States ◽  
The United States ◽  
Initial Study ◽  
Most Probable Number ◽  
Production Volume ◽  
Limited Data ◽  
Probable Number ◽  
The Past ◽  
Growing Region ◽  
Concentration Levels

ABSTRACT Recalls and outbreaks associated with Salmonella contamination in peanut-containing products have been reported over the past several years. Very limited data existed on the prevalence and concentration of Salmonella on raw, shelled peanuts in the United States. An initial study was completed in 2012 to estimate the prevalence and concentration of Salmonella on Runner- and Virginia-type raw, shelled peanuts in the United States from the 2008 through 2011 crop years, which were proportionately sampled from each growing region based on 2007 production volume. That study was extended to include samples of Runner- and Virginia-type peanuts from 2013, 2014, and 2015 crop years proportionately sampled from each growing region on the basis of the 2008 through 2010 volumes. Of the total 2,506 raw, shelled peanut samples, 41 (1.63%) were positive for Salmonella by the VIDAS SLM assay. Salmonella serovars identified in this study included Agona, Anatum, Bardo, Braenderup, Cannstatt, Dessau, Gaminara, Litchfield, Hartford, Inverness, Mbandaka, Meleagridis, Muenchen, Newport, Pakistan, Rodepoort, Rubislaw, Tennessee, and Tornow. The concentration levels of Salmonella in positive samples, as determined by most probable number (MPN), ranged from <0.003 to 2.4 MPN/g. These data will be useful when designing and validating processes for the reduction or elimination of Salmonella in peanuts or peanut-containing products or both.

Vibrio vulnificus and Vibrio parahaemolyticus in U.S. Retail Shell Oysters: A National Survey from June 1998 to July 1999

2002 ◽  
Vol 65 (1) ◽  
pp. 79-87 ◽  
Author(s):  
DAVID W. COOK ◽  
PAUL O'LEARY ◽  
JEFF C. HUNSUCKER ◽  
EDNA M. SLOAN ◽  
JOHN C. BOWERS ◽  
...  
Keyword(s):  
United States ◽  
North Atlantic ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Gulf Coast ◽  
The United States ◽  
Most Probable Number ◽  
Probable Number ◽  
Hemolysin Gene ◽  
Thermostable Direct Hemolysin

From June 1998 to July 1999, 370 lots of oysters in the shell were sampled at 275 different establishments (71%, restaurants or oyster bars; 27%, retail seafood markets; and 2%, wholesale seafood markets) in coastal and inland markets throughout the United States. The oysters were harvested from the Gulf (49%), Pacific (14%), Mid-Atlantic (18%), and North Atlantic (11%) Coasts of the United States and from Canada (8%). Densities of Vibrio vulnificus and Vibrio parahaemolyticus were determined using a modification of the most probable number (MPN) techniques described in the Food and Drug Administration's Bacteriological Analytical Manual. DNA probes and enzyme immunoassay were used to identify suspect isolates and to determine the presence of the thermostable direct hemolysin gene associated with pathogenicity of V. parahaemolyticus. Densities of both V. vulnificus and V. parahaemolyticus in market oysters from all harvest regions followed a seasonal distribution, with highest densities in the summer. Highest densities of both organisms were observed in oysters harvested from the Gulf Coast, where densities often exceeded 10,000 MPN/g. The majority (78%) of lots harvested in the North Atlantic, Pacific, and Canadian Coasts had V. vulnificus densities below the detectable level of 0.2 MPN/g; none exceeded 100 MPN/g. V. parahaemolyticus densities were greater than those of V. vulnificus in lots from these same areas, with some lots exceeding 1,000 MPN/g for V. parahaemolyticus. Some lots from the Mid-Atlantic states exceeded 10,000 MPN/g for both V. vulnificus and V. parahaemolyticus. Overall, there was a significant correlation between V. vulnificus and V. parahaemolyticus densities (r = 0.72, n = 202, P < 0.0001), but neither density correlated with salinity. Storage time significantly affected the V. vulnificus (10% decrease per day) and V. parahaemolyticus (7% decrease per day) densities in market oysters. The thermostable direct hemolysin gene associated with V. parahaemolyticus virulence was detected in 9 of 3,429 (0.3%) V. parahaemolyticus cultures and in 8 of 198 (4.0%) lots of oysters. These data can be used to estimate the exposure of raw oyster consumers to V. vulnificus and V. parahaemolyticus.

An International Outbreak of Salmonella Nima from Imported Chocolate

1989 ◽  
Vol 52 (1) ◽  
pp. 51-54 ◽  
Author(s):  
J. C. HOCKIN ◽  
J.-Y. D'AOUST ◽  
D. BOWERING ◽  
J. H. JESSOP ◽  
B. KHANNA ◽  
...  
Keyword(s):  
United States ◽  
Quantitative Analysis ◽  
Clinical Symptoms ◽  
Gold Foil ◽  
The United States ◽  
Most Probable Number ◽  
Product Recall ◽  
Primary Case ◽  
Probable Number ◽  
Composite Samples

Twenty-nine confirmed cases of Salmonella nima enterocolitis in Canada and four cases in the United States were traced to gold-foil wrapped chocolate coins from Belgium. Illness in Canadian cases occurred between September 1985 and October 1986 where the primary case in each of 24 affected families was a child ≤ 14 years of age. A product recall was issued on October 3, 1986 in Canada. Quantitative analysis of four composite samples of suspect chocolate by the most probable number (MPN) technique showed levels of 4.3 to 24.0 S. nima per 100 g product. These levels of contamination and consumption of approximately 25 g of chocolate by primary cases suggest that small numbers of S. nima precipitated clinical symptoms.

Prevalence and Concentration of Salmonella on Raw Shelled Peanuts in the United States

2013 ◽  
Vol 76 (4) ◽  
pp. 575-579 ◽  
Author(s):  
STEPHEN CALHOUN ◽  
LAURIE POST ◽  
BENJAMIN WARREN ◽  
STERLING THOMPSON ◽  
ANN ROGERS BONTEMPO
Keyword(s):  
United States ◽  
The United States ◽  
Most Probable Number ◽  
Production Volume ◽  
Limited Data ◽  
Probable Number ◽  
The Past ◽  
Salmonella Assay ◽  
Growing Region ◽  
Concentration Levels

Recalls and/or outbreaks associated with Salmonella contamination in peanut-containing products were reported over the past several years. There are very limited data available on the prevalence and concentration of Salmonella on raw shelled peanuts in the United States. The objectives of this study were to estimate the prevalence of Salmonella on raw shelled peanuts in the United States and to estimate that concentration of Salmonella. Samples of Runner- and Virginia-type raw shelled peanuts from the 2008, 2009, and 2010 crop years were proportionately sampled from each growing region, based on 2007 production volume. Of 944 raw shelled peanut samples (375 g each), 22 (2.33%) were positive for Salmonella by the VIDAS Salmonella assay. Salmonella serovars identified in this study included Agona, Anatum, Braenderup, Dessau, Hartford, Meleagridis, Muenchen, Rodepoort, Tennessee, and Tornow. The concentration levels of Salmonella in positive samples, as determined by a most-probable-number assay, were <0.03 to 2.4 MPN/g. These data will be useful when designing and validating processes for the reduction or elimination of Salmonella in peanuts and/or peanut-containing products.

Survey of Foodborne Pathogens, Aerobic Plate Counts, Total Coliform Counts, and Escherichia coli Counts in Leafy Greens, Sprouts, and Melons Marketed in the United States

2018 ◽  
Vol 81 (3) ◽  
pp. 400-411 ◽  
Author(s):  
Guodong Zhang ◽  
Yi Chen ◽  
Lijun Hu ◽  
David Melka ◽  
Hua Wang ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
The United States ◽  
Total Coliform ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Leafy Greens ◽  
Plate Counts

ABSTRACT The objective of this research was to assess the microbiological status of leafy greens, sprouts, and melons from U.S. markets. A total of 14,183 samples of leafy greens, 2,652 samples of sprouts, and 3,411 samples of melons were collected throughout the United States from 2009 to 2014. The samples were analyzed for aerobic plate counts, total coliform counts, Escherichia coli counts, and the presence and levels of Salmonella, Shigella, Listeria monocytogenes, and Shiga toxin–producing E. coli (STEC), depending on the year and type of produce. Among the leafy greens, no E. coli O157:H7 or non-O157 STEC were detected from iceberg lettuce samples. The overall prevalences of Salmonella, E. coli O157:H7, non-O157 STEC, and L. monocytogenes in the 14,183 samples of leafy greens were 0.05, 0.01, 0.07, and 0.11%, respectively. Among sprout samples, no Salmonella or E. coli O157:H7 was detected, and the overall prevalences of non-O157 STEC and L. monocytogenes were 0.04 and 0.11%, respectively. Among melon samples, no Salmonella was detected from cucumbers, no L. monocytogenes was detected from cantaloupes, and the overall prevalences of Salmonella and L. monocytogenes were 0.12 and 0.23%, respectively. L. monocytogenes levels were 0.4 to 1,470 most probable number (MPN)/g in leafy greens, 0.36 to 1,100 MPN/g in sprouts, and <0.03 to 150 MPN/g in melons, and most positive samples had low levels of these pathogens. The isolates from these foods were very diverse genetically. Foodborne pathogens, including Salmonella, STEC, and L. monocytogenes, had relatively low prevalences in the produce surveyed. Because these foods are usually consumed raw, measures should be taken to significantly minimize the presence and levels of human pathogens.

Physicochemical and Bacteriological Characteristics of Organic Sprouted Chia and Flax Seed Powders Implicated in a Foodborne Salmonellosis Outbreak

2016 ◽  
Vol 79 (5) ◽  
pp. 703-709 ◽  
Author(s):  
SANDEEP TAMBER ◽  
ELEONORA SWIST ◽  
DENISE OUDIT
Keyword(s):  
United States ◽  
Fatty Acid ◽  
Physicochemical Parameters ◽  
Acid Methyl Ester ◽  
The United States ◽  
Most Probable Number ◽  
Flax Seed ◽  
Probable Number ◽  
Acid Methyl ◽  
Foodborne Outbreaks

ABSTRACT Despite the increasing popularity of sprouted chia and flax seed powders, no data have been reported on their intrinsic physicochemical properties and background microflora. Here, we report the moisture content, water activity, pH, and fatty acid methyl ester and bacteriological profiles of 19 sprouted chia and flax seed samples, 10 of which were associated with an outbreak of salmonellosis in Canada and the United States. The physicochemical parameters of the Salmonella-positive samples did not differ significantly from those of the negative samples. However, the higher Enterobacteriaceae and coliform levels on the contaminated powders were associated with the presence of Salmonella. Enumeration of Salmonella by the most probable number (MPN) method revealed concentrations ranging from 1 MPN per 3 g of powder to 1 MPN per 556 g of powder. The results of this study demonstrate that low numbers of Salmonella may be linked to foodborne outbreaks.

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