Biochemical Modulation of Venom by Spiders is Achieved Via Compartmentalized Toxin Production and Storage

2019 ◽  
Author(s):  
David Morgenstern ◽  
Brett R. Hamilton ◽  
Darren Korbie ◽  
Karl R. Clauser ◽  
Brian J. Haas ◽  
...  
Keyword(s):  
Toxin Production ◽  
Biochemical Modulation ◽  
And Storage

Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus

2016 ◽  
Vol 79 (1) ◽  
pp. 148-152 ◽  
Author(s):  
TIAN DING ◽  
YAN-YAN YU ◽  
CHENG-AN HWANG ◽  
QING-LI DONG ◽  
SHI-GUO CHEN ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Water Activity ◽  
Storage Temperature ◽  
Probability Model ◽  
Toxin Production ◽  
Factors Affecting ◽  
Model Predictions ◽  
And Storage ◽  
Storage Temperatures ◽  
Good Agreement

ABSTRACT The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (aw), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of aw (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that aw, pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and aw and storage temperatures to prevent SEA production.

scholarly journals Influence of soft cheese technology on the growth and enterotoxin production of Staphylococcus aureus

2009 ◽  
Vol 27 (No. 2) ◽  
pp. 127-133 ◽  
Author(s):  
L. Necidová ◽  
Z. Šťástková ◽  
M. Pospíšilová ◽  
B. Janštová ◽  
J. Strejček ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Technological Process ◽  
Raw Milk ◽  
Toxin Production ◽  
Milk Products ◽  
Model Experiments ◽  
Soft Cheese ◽  
Strict Compliance ◽  
Technological Processing ◽  
And Storage

The aim of this study was to monitor <I>S. aureus</I> growth and toxin production in soft cheese during the technological processing. In model experiments, raw milk was inoculated separately with five <I>S. aureus</I> strains isolated from milk and milk products. All the strains were producers of staphylococcal enterotoxins (SEs) of types A, B, or C. SEs were detected by the enzyme-linked fluorescence assay (ELFA) performed in the MiniVIDAS device. This study has shown that the amount of SEs varied with the tested strains and stages of the technological process. SEs were detected in soft cheese made from pasteurised milk inoculated with 2.9 × 10<sup>5</sup> CFU/g of <I>S. aureus</I>. The prevention of <I>S. aureus</I> contamination and multiplication during the cheese making process is a prerequisite for the production of safe soft cheese. The most important enterotoxin dose build-up factor can be overcome by strict compliance with the cooling requirements during the manufacture, distribution and storage of the product.

Effect of Equilibrated pH and Indigenous Spoilage Microorganisms on the Inhibition of Proteolytic Clostridium botulinum Toxin Production in Experimental Meals under Temperature Abuse

2017 ◽  
Vol 80 (8) ◽  
pp. 1252-1258 ◽  
Author(s):  
Max C. Golden ◽  
Brandon J. Wanless ◽  
Jairus R. D. David ◽  
D. Scott Lineback ◽  
Ryan J. Talley ◽  
...  
Keyword(s):  
Botulinum Toxin ◽  
Clostridium Botulinum ◽  
Storage Temperature ◽  
Phase 1 ◽  
Toxin Production ◽  
Brussels Sprouts ◽  
The Impact ◽  
And Storage ◽  
Spoilage Microorganisms ◽  
Toxin Formation

ABSTRACT Clostridium botulinum is a foreseeable biological hazard in prepared refrigerated meals that needs to be addressed in food safety plans. The objective of this study was to evaluate the effect of product composition and storage temperature on the inhibition of botulinum toxin formation in nine experimental meals (meat, vegetable, or carbohydrate based). Treatments were inoculated with proteolytic C. botulinum, vacuum packaged, cooked at 90°C for 10 min, and assayed for botulinum toxin in samples stored at 25°C for up to 96 h for phase 1, or at 25°C for 12 h and then transferred to 12.5°C for up to 12 and 6 weeks in phases 1 and 2, respectively. For phase 1, none of the treatments (equilibrated pH 5.8) supported toxin production when stored at 25°C for 48 h, but toxin production was observed in all treatments at 72 h. For the remaining experiments with storage at 12.5°C, toxin production was dependent on equilibrated pH, storage time, and growth of indigenous spoilage microorganisms. In phase 1, no gross spoilage and no botulinum toxin was detected for any treatment (pH ≤5.8) stored at 12.5°C for 12 weeks. In phase 2, gross spoilage varied by commodity, with the brussels sprouts meal with pH 6.5 showing the most rapid spoilage within 2 weeks and botulinum toxin detected at 5 and 6 weeks for the control and cultured celery juice treatments, respectively. In contrast, spoilage microbes decreased the pH of a pH 5.9 beef treatment by 1.0 unit, potentially inhibiting C. botulinum through 6 weeks at 12.5°C. None of the other treatments with pH 5.8 or below supported toxin production or spoilage. This study provides validation for preventive controls in refrigerated meals. These include equilibrated product pH and storage temperature and time to inhibit toxin formation by proteolytic C. botulinum, but the impact of indigenous microflora on safety and interpretation of challenge studies is also highlighted.

Conservative Prediction of Time to Clostridium botulinum Toxin Formation for Use with Time-Temperature Indicators To Ensure the Safety of Foods

1998 ◽  
Vol 61 (9) ◽  
pp. 1154-1160 ◽  
Author(s):  
GUY E. SKINNER ◽  
JOHN W. LARKIN
Keyword(s):  
Botulinum Toxin ◽  
Empirical Relationship ◽  
Critical Time ◽  
Food Product ◽  
Toxin Production ◽  
Storage Conditions ◽  
Potential Health ◽  
And Storage ◽  
Infinite Set ◽  
Toxin Formation

Integrating-type time-temperature indicators (TTIs) may be utilized to warn food processors and consumers about storage conditions that may have rendered a food potentially hazardous. As an example of how integrated TTIs could be manufactured to emulate an infinite set of time-temperature situations, a set of conditions which have supported C. botulinum growth and toxin production was compiled. The time-temperature curve representing conservative times required for toxin formation was constructed with data from literature relating to toxin formation as a function of temperature in any media or food product. This set of critical time-temperature data is fit by a conservative empirical relationship that can be used to predict combinations of incubation times and storage temperatures that represent a potential health risk from C. botulinum in foods. A TTI could be constructed to indicate deviation from such a given set of conditions to bring attention to foods that may have been exposed to potentially hazardous temperatures with respect to C. botulinum toxin formation.

Clostridium botulinum and Acid Foods1,2

1978 ◽  
Vol 41 (7) ◽  
pp. 566-573 ◽  
Author(s):  
THERON E. ODLAUG ◽  
IRVING J. PFLUG
Keyword(s):  
Clostridium Botulinum ◽  
Toxin Production ◽  
Storage Conditions ◽  
Heat Process ◽  
Post Process ◽  
And Storage ◽  
The Way

Outbreaks of botulism involving acid foods are rare. Of the 722 total botulism outbreaks reported from 1899 to 1975, only 34 (4.7%) involved acid foods. Home-canned acid foods were implicated in 34 of the 35 acid food outbreaks. Clostridium botulinum cannot grow at a pH of ⩽ 4.6; therefore, for a botulism hazard to exist in an acid food, a contamination with other microorganisms due to a process delivery failure and/or post-process contamination, (c) favorable composition of the food and storage conditions which are particularly conducive to C. botulinum growth and toxin production, and (d) metabiosis. The way each factor affects the botulism hazard in acid foods is discussed in this report. An acid food is safe from C. botulinum if the heat process kills all organisms capable of growth at a pH of ⩽4.6 and there is no post-process contamination.

Predictive Model Describing the Effect of Prolonged Heating at 70 to 80°C and Incubation at Refrigeration Temperatures on Growth and Toxigenesis by Nonproteolylic Clostridium botulinum

1997 ◽  
Vol 60 (9) ◽  
pp. 1064-1071 ◽  
Author(s):  
PABLO S. FERNÁNDEZ ◽  
MICHAEL W. PECK
Keyword(s):  
Predictive Model ◽  
Clostridium Botulinum ◽  
Incubation Temperature ◽  
Storage Temperature ◽  
Heating Temperature ◽  
Toxin Production ◽  
Heat Treatments ◽  
Prolonged Heating ◽  
Time Required ◽  
And Storage

There is growing interest in the food industry in the use of long heat treatments in the range of 70 to 90°C to produce minimally processed foods that have an extended shelf life at refrigeration temperatures. The risk of growth and toxin production by nonproteolytic Clostridium botulinum in these foods is of concern. The effect of heat treatments at 70, 75, 80, 85, and 90°C combined with refrigerated storage for 90 days on growth from 106 spores of nonproteolytic C. botulinum (types B, E, and F) in an anaerobic meat medium was studied. The following heat treatments prevented growth and toxin production during 90 days provided that the storage temperature was no higher than l2°C: 75°C for ≥1,072 min, 80°C for ≥230 min, 85°C for ≥36 min, and 90°C for ≥10 min. Following heating at 70°C for 2,545 min and storage at 12°C, growth was first observed after 22 days. A factorial experimental design allowed a predictive model to be developed that described the incubation time required before the first sample showed growth as a function of heating temperature (70 to 80°C), period of heat treatment (up to 2,545 min), and incubation temperature (5 to 25°C). Predictions from the model provided a valid description of the data used to generate the model, and agreed with observations made previously.

A Probability Model for Enterotoxin Production of Bacillus cereus as a Function of pH and Temperature

2013 ◽  
Vol 76 (2) ◽  
pp. 343-347 ◽  
Author(s):  
TIAN DING ◽  
JUN WANG ◽  
MYOUNG-SU PARK ◽  
CHENG-AN HWANG ◽  
DEOG-HWAN OH
Keyword(s):  
Bacillus Cereus ◽  
Storage Temperature ◽  
Probability Model ◽  
Food Poisoning ◽  
Toxin Production ◽  
Severe Nausea ◽  
Enterotoxin Production ◽  
Test Kit ◽  
And Storage ◽  
Selection Of

Bacillus cereus is frequently isolated from a variety of foods, including vegetables, dairy products, meats, and other raw and processed foods. The bacterium is capable of producing an enterotoxin and emetic toxin that can cause severe nausea, vomiting, and diarrhea. The objectives of this study were to assess and model the probability of enterotoxin production of B. cereus in a broth model as affected by the broth pH and storage temperature. A three-strain mixture of B. cereus was inoculated in tryptic soy broth adjusted to pH 5.0, 6.0, 7.2, 8.0, and 8.5, and the samples were stored at 15, 20, 25, 30, and 35°C for 24 h. A total of 25 combinations of pH and temperature, each with 10 samples, were tested. The presence of enterotoxin in broth was assayed using a commercial test kit. The probabilities of positive enterotoxin production in 25 treatments were fitted with a logistic regression to develop a probability model to describe the probability of toxin production as a function of pH and temperature. The resulting model showed that the probabilities of enterotoxin production of B. cereus in broth increased as the temperature increased and/or as the broth pH approached 7.0. The model described the experimental data satisfactorily and identified the boundary of pH and temperature for the production of enterotoxin. The model could provide information for assessing the food poisoning risk associated with enterotoxins of B. cereus and for the selection of product pH and storage temperature for foods to reduce the hazards associated with B. cereus.

Combined Effect of Modified Atmosphere Packaging and Low-Dose Irradiation on Toxin Production by Clostridium botulinum in Fresh Pork

1991 ◽  
Vol 54 (2) ◽  
pp. 94-101 ◽  
Author(s):  
ANNE D. LAMBERT ◽  
JAMES P. SMITH ◽  
KAREN L. DODDS
Keyword(s):  
Clostridium Botulinum ◽  
Irradiation Dose ◽  
Storage Temperature ◽  
Modified Atmosphere Packaging ◽  
Toxin Production ◽  
Combined Effect ◽  
Modified Atmosphere ◽  
Headspace Oxygen ◽  
And Storage ◽  
Design Experiments

The combined effect of three initial levels of oxygen (0, 10, and 20%), irradiation dose (0, 0.5, and 1 kGy), and storage temperature (5, 15, and 25°C) on toxin production by Clostridium botulinum in inoculated modified atmosphere packaged pork were investigated using factorial design experiments. Toxin was detected after only 2 d in all treatments stored at 25°C. At 15°C, irradiated and nonirradiated product packaged with 10 or 20% headspace oxygen were toxic after 14 d. For product packaged with 0% oxygen and an oxygen absorbent, toxin was detected after 21 d in nonirradiated samples compared to 43 d for product treated with an irradiation dose of 1 kGy. No toxin was detected in any product stored at 5°C, even after 44 d. Headspace oxygen in product initially packaged with 20% oxygen decreased to 0.1% after 14 d at 15°C and to ≤3% after 5 d at 25°C, with a concomitant increase in package headspace CO2 to 25–40%. For product packaged with 0% O2 and an oxygen absorbent, oxygen remained at ≤2% throughout the storage trial, while CO2 increased to 10 and 24% for nonirradiated and irradiated samples, respectively. Initial packaging of product with O2 appeared to enhance toxin production by C. botulinum in product stored at 15°C, probably as a result of increased CO2 enhancing spore germination.

An Overview of Digital Image Processing and Recognition (Invited Paper)

1982 ◽  
Vol 40 ◽  
pp. 700-702
Author(s):  
R. C. Gonzalez
Keyword(s):  
Image Processing ◽  
New York ◽  
Digital Image Processing ◽  
Digital Image ◽  
Practical Implementation ◽  
Submarine Cable ◽  
Vigorous Growth ◽  
Digitized Pictures ◽  
Processing Techniques ◽  
And Storage

Interest in digital image processing techniques dates back to the early 1920's, when digitized pictures of world news events were first transmitted by submarine cable between New York and London. Applications of digital image processing concepts, however, did not become widespread until the middle 1960's, when third-generation digital computers began to offer the speed and storage capabilities required for practical implementation of image processing algorithms. Since then, this area has experienced vigorous growth, having been a subject of interdisciplinary research in fields ranging from engineering and computer science to biology, chemistry, and medicine.

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