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.

scholarly journals Survey for Listeria monocytogenes in and on Ready-to-Eat Foods from Retail Establishments in the United States (2010 through 2013): Assessing Potential Changes of Pathogen Prevalence and Levels in a Decade

2017 ◽  
Vol 80 (6) ◽  
pp. 903-921 ◽  
Author(s):  
John B. Luchansky ◽  
Yuhuan Chen ◽  
Anna C. S. Porto-Fett ◽  
Régis Pouillot ◽  
Bradley A. Shoyer ◽  
...  
Keyword(s):  
United States ◽  
Listeria Monocytogenes ◽  
The United States ◽  
Food Samples ◽  
Most Probable Number ◽  
Grocery Stores ◽  
Probable Number ◽  
Logistic Regression Models ◽  
United States Food ◽  
Pathogen Prevalence

ABSTRACTA multiyear interagency Listeria monocytogenes Market Basket Survey was undertaken for selected refrigerated ready-to-eat foods purchased at retail in four FoodNet sites in the United States. Food samples from 16 food categories in six broad groups (seafood, produce, dairy, meat, eggs, and combination foods) were collected weekly at large national chain supermarkets and independent grocery stores in California, Maryland, Connecticut, and Georgia for 100 weeks between December 2010 and March 2013. Of the 27,389 total samples, 116 samples tested positive by the BAX PCR system for L. monocytogenes, and the pathogen was isolated and confirmed for 102 samples. Among the 16 food categories, the proportion of positive samples (i.e., without considering clustering effects) based on recovery of a viable isolate of L. monocytogenes ranged from 0.00% (95% confidence interval: 0.00, 0.18) for the category of soft-ripened and semisoft cheese to 1.07% (0.63, 1.68) for raw cut vegetables. Among the 571 samples that tested positive for Listeria-like organisms, the proportion of positive samples ranged from 0.79% (0.45, 1.28) for soft-ripened and semisoft cheese to 4.76% (2.80, 7.51) for fresh crab meat or sushi. Across all 16 categories, L. monocytogenes contamination was significantly associated with the four states (P < 0.05) but not with the packaging location (prepackaged by the manufacturer versus made and/or packaged in the store), the type of store (national chain versus independent), or the season. Among the 102 samples positive for L. monocytogenes, levels ranged from <0.036 most probable number per g to 6.1 log CFU/g. For delicatessen (deli) meats, smoked seafood, seafood salads, soft-ripened and semisoft cheeses, and deli-type salads without meat, the percentage of positive samples was significantly lower (P < 0.001) in this survey than that reported a decade ago based on comparable surveys in the United States. Use of mixed logistic regression models to address clustering effects with regard to the stores revealed that L. monocytogenes prevalence ranged from 0.11% (0.03, 0.34) for sprouts (prepackaged) to 1.01% (0.58, 1.74) for raw cut vegetables (prepackaged).

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.

Variability in Broiler Carcass Bacterial Load at Three Abattoirs, as Measured by a Hydrophobic Grid Membrane Filter Interpreter

1993 ◽  
Vol 56 (8) ◽  
pp. 700-705 ◽  
Author(s):  
W. BRUCE MCNAB ◽  
SHANE A. RENWICK ◽  
H. RUFFNER LOWMAN ◽  
ROBERT C. CLARKE
Keyword(s):  
Correlation Coefficient ◽  
Membrane Filter ◽  
Geometric Mean ◽  
Bacterial Load ◽  
Bacterial Count ◽  
Most Probable Number ◽  
Data Set ◽  
Probable Number ◽  
Individual Bird ◽  
Measurement Protocol

In this observational study, the variability of broiler carcass bacterial load was investigated at three federally inspected abattoirs, using an automated hydrophobic grid membrane filter interpreter system. The measurement protocol involved: whole carcass rinses aided by a mechanical carcass shaker; filtration of rinse solutions through hydrophobic grid membrane filters (HGMF) (ISO-GRID®, QA Laboratories, Ltd., Toronto, Ont.); and use of an automated HGMF interpreter (MI-100 HGMF Interpreter System, Richard Brancker Research, Ltd., Ottawa, Ont.). Carcass and lot mean bacterial loads were measured, respectively, in units of log10 most probable number (MPN) of mesophylic aerobic colony forming units per gram of carcass (LgMPN/g), and slaughter lot mean LgMPN/g (LMLgMPN/g). Whole carcass rinses were conducted on a total of 1,917 carcasses, among 96 slaughter lots from three abattoirs. Overall, the LgMPN/g ranged from 1.054 to 4.180 with a mean of 2.585 and a variance of 0.263. These corresponded to MPN/g counts from 11 to 15,135 and a geometric mean of 385 MPN/g. Statistically significant differences were observed between abattoirs and between lots within abattoirs. The intra-abattoir correlation coefficient of LgMPN/g was r = 0.180 (p < 0.001). The within abattoir intralot correlation coefficient was r = 0.259 (p < 0.001). In this data set, approximately 56, 26, and 18% of the variability in LgMPN/g were attributed to factors operating at the individual bird, lot, and abattoir levels of organization, respectively. Factors significantly associated with LMLgMPN/g included: abattoir (p < 0.001), transportation time from farm to abattoir (p < 0.001), and waiting time from arrival at the abattoir yard to actual slaughter (p = 0.002). Analysis of a series of five repeat rinses, conducted on one bird from each of the 96 study lots, demonstrated that bacterial counts in the second to fifth sequential rinses were positively associated with the bacterial count of the first rinse. Also, after adjusting for the initial count, a pattern of decreasing counts was observed in subsequent rinses.

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.

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.

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.

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