THE FATE OF SALMONELLA TYPHIMURIUM IN THE MANUFACTURE AND RIPENING OF LOW-ACID CHEDDAR CHEESE1

1970 ◽  
Vol 33 (7) ◽  
pp. 280-284 ◽  
Author(s):  
H. S. Park ◽  
E. H. Marth ◽  
J. M. Goepfert ◽  
N. F. Olson
Keyword(s):  
Salmonella Typhimurium ◽  
Starter Culture ◽  
Most Probable Number ◽  
Initial Increase ◽  
High Moisture ◽  
Gradual Decline ◽  
Probable Number ◽  
Streptococcus Lactis ◽  
Extended Survival ◽  
Made In

Cheddar cheese was made by the stirred-curd procedure from pasteurized milk inoculated with Salmonellea typhimurium and with a slow acid-producing strain of Streptococcus lactis. The Most Probable Number technique was used to enumerate salmonellae in milk and in cheese during its manufacture and ripening. Salmonellae grew rapidly during manufacture and limited additional growth occurred in cheese during the first week of ripening at 13 C after which there was a gradual decline in population. Salmonellae survived during ripening for up to approximately 7 months at 13 C and 10 months at 7 C. Cheese made in 2 of 5 trials exhibited a limited increase in number of salmonellae during the first 2 weeks at 7 C followed by a decline in population of these bacteria. Other cheeses held at 7 C exhibited a reduction in number of viable salmonellae without the initial increase. Growth of salmonellae during the early stages of ripening and subsequent extended survival of these organisms may, in part, be attributable to high moisture (average 43.2%) and high pH (5.75 after overnight pressing) of the cheese which resulted from use of a slow acid-producing starter culture.

scholarly journals Agroclimatic classification for assessment Of the crop potential of Karnataka

MAUSAM ◽  
2021 ◽  
Vol 43 (1) ◽  
pp. 91-98
Author(s):  
Dr. (SMT.) N.N. KHAMBETE
Keyword(s):  
Crop Production ◽  
Most Probable Number ◽  
Cropping Pattern ◽  
Probable Number ◽  
Dry Spells ◽  
Agricultural Potential ◽  
Climatic Classification ◽  
Availability Index ◽  
Dry Farming ◽  
Made In

To plan cropping pattern and to bring out agricultural potential of a region, it is essential that the agro climatic classification is made on an objective and rational basis. Such an attempt has been made in this paper by devising an index called Water Availability Index (WAI). This index takes into account the distribution of the minimum water required by the crop. It utilizes the most probable number of the wet weeks for three threshold values of weekly rainfall and probability of dry spells of more than three weeks. The methodology developed is applied to dry farming tracts of Karnataka State. Using these information along with the information of the soil types and water requirement of different crops, cropping pattern can be assessed in each agro climatic zone, so that optimum use of the available moisture is made in stabilizing the crop production in the State.  

Rapid Fluorogenic Enumeration of Escherichia coli in Selected, Naturally Contaminated High Moisture Foods

1987 ◽  
Vol 70 (6) ◽  
pp. 991-993
Author(s):  
Paul L Poelma ◽  
Clyde R Wilson ◽  
Wallace H Andrews
Keyword(s):  
Escherichia Coli ◽  
Ultraviolet Light ◽  
Ground Beef ◽  
Most Probable Number ◽  
High Moisture ◽  
Probable Number ◽  
Pork Sausage ◽  
E Coli

Abstract An assay for the enzyme glucuronidase was used to determine the presence of Escherichia coli in selected, naturally contaminated high moisture foods. Raw pork sausage, ground turkey, and ground beef were inoculated into tubes containing the substrate 4-methylumbelliferyl beta-D-glucuronide (MUG) in lauryl tryptose (LT) medium. After incubation at 35°C for 24 h, the inoculated LT-MUG tubes were examined under longwave ultraviolet light for the presence of a fluorogenic glucuronidase end product. A fluorescing tube indicated the presumptive presence of E. coli. The 10 day most probable number method of the AOAC and the LT-MUG procedure gave comparable recoveries of E. coli.

Modeling Prevalence and Counts from Most Probable Number in a Bayesian Framework: An Application to Salmonella Typhimurium in Fresh Pork Sausages

2010 ◽  
Vol 73 (8) ◽  
pp. 1416-1422 ◽  
Author(s):  
URSULA GONZALES-BARRON ◽  
GRAINNE REDMOND ◽  
FRANCIS BUTLER
Keyword(s):  
United Kingdom ◽  
Confidence Interval ◽  
Salmonella Typhimurium ◽  
Assessment Model ◽  
Most Probable Number ◽  
Probable Number ◽  
Pork Sausage ◽  
The United Kingdom ◽  
Viable Cells ◽  
Pork Sausages

Prevalence and counts of Salmonella Typhimurium in fresh pork sausage packs at the point of retail were modeled by using Irish and United Kingdom retail surveys' data. A methodology for modeling a second-order distribution for the initial Salmonella concentration (λ0) in pork sausage at retail was presented considering the uncertainty originated from the most-probable-number (MPN) serial dilutions. A conditional probability of observing the tube counts given true Salmonella concentration in a contaminated pack was built from the MPN triplets of every sausage tested. A posterior distribution was then modeled under the assumption that the counts from each of the portions of sausage mix stuffed into casings (and subsequently packed) are Poisson distributed. In order to model the variability of λ0 among contaminated sausage packs, MPN uncertainties were propagated to a predefined lognormal distribution. Because the sausage samples from the Irish survey were frozen prior to MPN analysis (which is expected to cause reduction in viable cells), the resulting distribution for λ0 appeared greatly underestimated (mean: 0.514 CFU/g; 95% confidence interval [CI]: 0.02 to 2.74 CFU/g). The λ0 distribution produced with the United Kingdom survey data (mean: 69.7 CFU/g; 95% CI: 15 to 200 CFU/g) was, however, more conservative, and is to be used along with the fitted distribution for prevalence of Salmonella Typhimurium in pork sausage packs in Ireland (gamma[37.997, 0.0013]; mean: 0.046; 95% CI: 0.032 to 0.064) as the main inputs of a stochastic consumer-phase exposure assessment model.

Managing soils to enhance the potential for bioremediation of water repellency

Soil Research ◽  
2005 ◽  
Vol 43 (7) ◽  
pp. 803 ◽  
Author(s):  
Margaret M. Roper
Keyword(s):  
Management Practices ◽  
Crop Yields ◽  
Water Repellency ◽  
Water Infiltration ◽  
Most Probable Number ◽  
Water Repellent ◽  
Gradual Decline ◽  
Kaolinite Clay ◽  
Probable Number ◽  
Degrading Bacteria

Water repellency can significantly reduce crop and pasture establishment and production in sandy soils. Management practices that increase the rate of water infiltration into dry soils following the first rains at the end of the dry season were investigated. In the laboratory, addition of water to water repellent soil and maintenance of warm moist conditions produced a gradual decline in water repellency. This was supported by results in the field which showed that under daily irrigation there was a gradual decline in water repellency over time. However, under dryland conditions, other mechanisms to increase water infiltration had to be found. In the laboratory, after the addition of lime and kaolinite clay, there was an initial rapid decline in repellency, indicative of a physical mechanism, followed by a more gradual decline suggesting a biological response. In the field, under dryland conditions, the addition of lime and kaolinite clay resulted in a reduction in water repellency, and in the case of lime, this effect increased with the size of application. Estimates of the numbers of wax-degrading bacteria in the treated soils, using a most-probable-number assay, showed at least a 10-fold increase in lime-treated sands, but not in the clay-treated sands. The results suggest that lime may provide a viable alternative for increasing the wettability of soils by physical mechanisms and by promoting microbial activity by bacteria responsible for wax degradation, resulting in more consistent plant germination and establishment, and increased crop yields.

Validation of a Tertiary Model for Predicting Variation of Salmonella Typhimurium DT104 (ATCC 700408) Growth from a Low Initial Density on Ground Chicken Breast Meat with a Competitive Microflora†

2006 ◽  
Vol 69 (9) ◽  
pp. 2048-2057 ◽  
Author(s):  
T. P. OSCAR
Keyword(s):  
Salmonella Typhimurium ◽  
Phage Type ◽  
Model Development ◽  
Initial Density ◽  
Most Probable Number ◽  
Chicken Breast ◽  
Breast Meat ◽  
Probable Number ◽  
Primary Model ◽  
Chicken Breast Meat

Growth of a multiple antibiotic–resistant strain (ATCC 700408) of Salmonella Typhimurium definitive phage type 104 (DT104) from a low initial density (100.6 most probable number [MPN] or CFU/g) on ground chicken breast meat with a competitive microflora was investigated and modeled as a function of time and temperature (10 to 40°C). MPN and viable counts (CFU) on a selective medium with four antibiotics enumerated the pathogen. Data from five replicate challenge studies per temperature were combined and fit to a primary model to determine maximum specific growth rate (μ), maximum population density (Nmax), and the 95% prediction interval (PI). Nonlinear regression was used to obtain secondary models as a function of temperature for μ, Nmax, and PI, which ranged from 0.04 to 0.4 h−1, 1.6 to 9.4 log MPN or CFU/g, and 1.4 to 2.4 log MPN or CFU/g, respectively. Secondary models were combined with the primary model to create a tertiary model for predicting variation (95% PI) of pathogen growth among batches of ground chicken breast meat with a competitive microflora. The criterion for acceptable model performance was that 90% of observed MPN or CFU data had to be in the 95% PI predicted by the tertiary model. For data (n = 344) used in model development, 93% of observed MPN and CFU data were in the 95% PI predicted by the tertiary model, whereas for data (n = 236) not used in model development but collected using the same methods, 94% of observed MPN and CFU data were in the 95% PI predicted by the tertiary model. Thus, the tertiary model was successfully verified against dependent data and validated against independent data for predicting variation of Salmonella Typhimurium DT104 growth among batches of ground chicken breast meat with a competitive microflora and from a low initial density.

FATE OF ENTEROPATHOGENIC STRAINS OF ESCHERICHIA COLI DURING THE MANUFACTURE AND RIPENING OF CAMEMBERT CHEESE1

1973 ◽  
Vol 36 (11) ◽  
pp. 543-546 ◽  
Author(s):  
H. S. Park ◽  
E. H. Marth ◽  
N. F. Olson
Keyword(s):  
Escherichia Coli ◽  
Rapid Growth ◽  
Starter Culture ◽  
Most Probable Number ◽  
Probable Number ◽  
Pasteurized Milk ◽  
E Coli ◽  
Streptococcus Cremoris ◽  
C 50 ◽  
Camembert Cheese

Camembert cheese was made from pasteurized milk inoculated to contain, per milliliter, approximately 100 cells of enteropathogenic strains of Echerichia coli. A Most Probable Number technique was used to enumerate E. coli at intervals during manufacture and ripening of the cheese. Identity of isolates obtained was determined serologically. Growth of E. coli was minimal until after curd was cut and hooped. Rapid growth ensued and populations in excess of 104/g appeared in some Cheeses 5 h after the Cheesemaking process began. Overnight storage of Cheese in hoops was accompanied by a decline in numbers of viable E. coli. This coincided with a drop in pH of the Cheese to 5.0 or below. Salting of cheese and 1 day of ripening at 15.6 C ( 60 F) caused a further decline in number of viable E. coli. This decline continued during the rest of the week at 15.6 C ( 60 F) and during storage at 10 C (50 F). From 0 to 9 weeks at 10 C (50 F) were required before cheese was free of viable E. coli. Substitution of Streptococcus cremoris C1 for a commercial lactic starter culture favored survival of E. coli so that 9-week old Cheese contained >104/g. When cheese was made from milk that contained penicillin, the E. coli population was approximately 109/g in 24-h old cheese and 107/g when the Cheese was 9 weeks old.

Microbiological Food Safety Status of Commercially Produced Tomatoes from Production to Marketing

2016 ◽  
Vol 79 (3) ◽  
pp. 392-406 ◽  
Author(s):  
BRIGITTE N. van DYK ◽  
WILLEKE de BRUIN ◽  
ERIKA M. du PLESSIS ◽  
LISE KORSTEN
Keyword(s):  
Food Safety ◽  
Salmonella Typhimurium ◽  
Contact Surface ◽  
Personal Hygiene ◽  
Most Probable Number ◽  
Source Water ◽  
Probable Number ◽  
E Coli ◽  
Processing Facility ◽  
The Impact

ABSTRACT Tomatoes have been implicated in various microbial disease outbreaks and are considered a potential vehicle for foodborne pathogens. Traceback studies mostly implicate contamination during production and/or processing. The microbiological quality of commercially produced tomatoes was thus investigated from the farm to market, focusing on the impact of contaminated irrigation and washing water, facility sanitation, and personal hygiene. A total of 905 samples were collected from three large-scale commercial farms from 2012 through 2014. The farms differed in water sources used (surface versus well) and production methods (open field versus tunnel). Levels of total coliforms and Escherichia coli and prevalence of E. coli O157:H7 and Salmonella Typhimurium were determined. Dominant coliforms were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. No pathogens or E. coli were detected on any of the tomatoes tested throughout the study despite the high levels of coliforms (4.2 to 6.2 log CFU/g) present on the tomatoes at the market. The dominant species associated with tomatoes belonged to the genera Enterobacter, Klebsiella, and Citrobacter. Water used on the farm for irrigation considered not fit for purpose according to national agricultural irrigation standards, with high E. coli levels resulting from either a highly contaminated source water (river water at 3.19 log most probable number [MPN]/100 ml) or improper storage of source water (stored well water at 1.72 log MPN/100 ml). Salmonella Typhimurium was detected on two occasions on a contact surface in the processing facility of the first farm in 2012. Contact surface coliform counts were 2.9 to 4.8 log CFU/cm2. Risk areas identified in this study were water used for irrigation and poor sanitation practices in the processing facility. Implementation of effective food safety management systems in the fresh produce industry is of the utmost importance to ensure product safety for consumers.

Bactericidal Effect of Sodium Chlorate on Escherichia coli O157:H7 and Salmonella Typhimurium DT104 in Rumen Contents In Vitro

2000 ◽  
Vol 63 (8) ◽  
pp. 1038-1042 ◽  
Author(s):  
ROBIN C. ANDERSON ◽  
SANDRA A. BUCKLEY ◽  
LEON F. KUBENA ◽  
LARRY H. STANKER ◽  
ROGER B. HARVEY ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Salmonella Typhimurium ◽  
Bactericidal Effect ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
E Coli ◽  
Respiratory Nitrate Reductase

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (≤10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean ± SD) of total culturable anaerobes (ranging from 9.9 ± 0.72 to 10.7 ± 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

Detection of Staphylococcus aureus Within Starter Culture Preparations Containing Staphylococcus carnosus

1994 ◽  
Vol 57 (11) ◽  
pp. 981-984 ◽  
Author(s):  
DÖRTHE FEUERSENGER ◽  
HERMANN J. KNAUF ◽  
JÜRGEN BAUMGART
Keyword(s):  
Staphylococcus Aureus ◽  
Detection Limit ◽  
Incubation Temperature ◽  
Starter Culture ◽  
Microbiological Quality ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Staphylococcus Carnosus ◽  
Drop Plate

A method is described that permits the detection of contamination by Staphylococcus aureus within starter culture preparations containing Staphylococcus carnosus. Using selective media and raised incubation temperature it was possible to distinguish between starter and contamination organisms. The detection limit was 103 S. aureus within 1011 S. carnosus by the drop-plate method. With a modified most probable number (MPN) technique the detection limit was even lower. The time needed varied between 24 and 72 h depending on the concentration of the contaminant and the method used. The method described therefore proved to be suitable for routine microbiological quality control regarding the microbiological status of starter preparations containing bulk starter staphylococci. The drop-plate method furthermore proved to be suitable for the detection of S. aureus within starter preparations of pediococci and lactobacilli.

Effects of Domestic Storage and Thawing Practices on Salmonella in Poultry-Based Meat Preparations

2015 ◽  
Vol 78 (12) ◽  
pp. 2117-2125 ◽  
Author(s):  
ANNA ROCCATO ◽  
MIEKE UYTTENDAELE ◽  
VERONICA CIBIN ◽  
FEDERICA BARRUCCI ◽  
VERONICA CAPPA ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Most Probable Number ◽  
Probable Number ◽  
Moderate Growth ◽  
Serovar Typhimurium ◽  
Handling Practices ◽  
Food Handling Practices ◽  
Short Time ◽  
The Impact

Among consumer food handling practices, time-temperature abuse has been reported as one of the most common contributory factors in salmonellosis outbreaks where the evidence is strong. The present study performed storage tests of burgers, sausages, and kebabs and investigated (i) the effect of refrigerator temperatures (4°C versus 8 or 12°C, which were the temperatures recorded in 33 and 3%, respectively, of domestic refrigerators in Italy), with or without prior temperature abuse (25°C for 2 h, simulating transport of meats from shop to home), and (ii) the impact of the thawing method (overnight in the refrigerator at 8°C versus on the kitchen countertop at 23°C) on the presence and numbers of Salmonella bacteria. Storage tests were carried out on naturally or artificially (Salmonella enterica serovar Typhimurium at ca. 10 CFU/g) contaminated products, while freezing-thawing tests were conducted only on artificially contaminated products (Salmonella Typhimurium at ca. 10, 100, and 1,000 CFU/g). The results from the artificially contaminated products showed significant (P < 0.05) growth of Salmonella Typhimurium at 12°C (i.e., from ca. 8 most probable number [MPN]/g to > 710 MPN/g) in kebabs after 7 and 10 days but more moderate growth in sausages (i.e., from ca. 14 MPN/g to a maximum of 96 MPN/g after 9 days of storage). Storage of naturally contaminated burgers or sausages (contamination at or below 1 MPN/g) at 4, 8, or 12°C and a short time of temperature abuse (2 h at 25°C) did not facilitate an increase in the presence and numbers of Salmonella bacteria. Thawing overnight in the refrigerator led to either a moderate reduction or no change of Salmonella Typhimurium numbers in burgers, sausages, and kebabs. Overall, this study showed that domestic storage and thawing practices can affect food safety and that time-temperature abuse can cause a substantial increase of Salmonella numbers in some types of poultry-based meat preparations, highlighting that efforts for the dissemination of consumer guidelines on the correct storage and handling of meats need to be continued.

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