Modelling the growth rate of Listeria monocytogenes with a multiplicative type model including interactions between environmental factors

ABSTRACT The growth characteristics of Listeria monocytogenes inoculated onto frozen foods (corn, green peas, crabmeat, and shrimp) and thawed by being stored at 4, 8, 12, and 20°C were investigated. The growth parameters, lag-phase duration (LPD) and exponential growth rate (EGR), were determined by using a two-phase linear growth model as a primary model and a square root model for EGR and a quadratic model for LPD as secondary models, based on the growth data. The EGR model predictions were compared with growth rates obtained from the USDA Pathogen Modeling Program, calculated with similar pH, salt percentage, and NaNO2 parameters, at all storage temperatures. The results showed that L. monocytogenes grew well in all food types, with the growth rate increasing with storage temperature. Predicted EGRs for all food types demonstrated the significance of storage temperature and similar growth rates among four food types. The predicted EGRs showed slightly slower rate compared with the values from the U.S. Department of Agriculture Pathogen Modeling Program. LPD could not be accurately predicted, possibly because there were not enough sampling points. These data established by using real food samples demonstrated that L. monocytogenes can initiate growth without a prolonged lag phase even at refrigeration temperature (4°C), and the predictive models derived from this study can be useful for developing proper handling guidelines for thawed frozen foods during production and storage.

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The rooting, survival and growth of woody species on tailing dumps in the limestone quarry “Lafarge ciment”

Journal of Botany ◽

10.52240/1857-2367.2021.1(22).02 ◽

2021 ◽

Vol 13 (1(22)) ◽

pp. 34-42

Author(s):

Petru Cuza ◽

◽

Corina Certan ◽

Constantin Bulimaga ◽

◽

...

Keyword(s):

Growth Rate ◽

Environmental Factors ◽

Slow Growth ◽

Woody Species ◽

Mineral Elements ◽

Black Pine ◽

Limestone Quarry ◽

Survival And Growth ◽

High Degree ◽

Fast Growing Species

The rooting, the survival and dynamics of growths in the height and after the diameter of the seedlings, of a range of woody species, had investigated on the freshly formed sterile dump limestone quarry „Lafarge Ciment”. The seedlings of the woody species had a relatively good rooting (69-99%). A high degree of rooting can be ensured as a result of the maintenance of forest crops. After planting, the young seedlings must be cared for by hoeing as many times as necessary in order to control the weeds and maintain moisture in the soil, which increases the survival of the seedlings. Tree species have been characterized by a different growth rate. Acacia has showed a very rapid increase in height, but the black pine has been characterized by a slow growth. Acacia being a fast-growing species and unpretentious to the mineral elements in the soil can be used to afforest the limestone quarry land. In the fi rst year after planting, the young seedlings, otherwise sensitive to the action of the environmental factors, had an increase in height and in diameter slow and uneven. In the years that followed, the seedlings became more viable and less infl uenced by local and temporal fl uctuations of environmental factors.

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Phytoremediation of Special Metals in Emerging Industries

Sustainable Forestry ◽

10.24294/sf.v1i3.932 ◽

2018 ◽

Vol 1 (3) ◽

Author(s):

T Y TEH ◽

Min-Hao Wu ◽

Kf Chen ◽

Yp Peng

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Growth Rate ◽

Environmental Factors ◽

Contaminated Soil ◽

Morphological Analysis ◽

Energy Crop ◽

Emerging Industries ◽

Incremental Growth ◽

Conventional Methods

This project is carried out to assess the remediation effect on soil contaminated by molybdenum (Mo), one of heavy metals, through the use of an energy crop, sunflowers. This project explores the integration of phytohormones and chelates in the phytoremediation of soils contaminated by heavy metals, and further assesses the operational measures of remedying heavy-metal contaminated soil with sunflowers, in addition to the related environmental factors. Then the project explores phytohormones and heavy metals on the growth scenario explants (explants morphological analysis) through the experiment. The results indicate that GA3 can increase the growth rate of the plants. The average incremental growth of the heavy-metal-added-only group is 21.0 cm; of the GA3-added group it is 21.9 cm; of the EDDS-added group, it is 20.3 cm; of the GA3+ EDDS-added group, it is 21.7 cm. Compared with the conventional methods of phytoremediation, these integrated measures can actually spur the growth of plants.

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Experiments on some effects of certain environmental factors on Gracilaria verrucosa (Hudson) Papenfuss

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400015666 ◽

1959 ◽

Vol 38 (1) ◽

pp. 153-167 ◽

Cited By ~ 32

Author(s):

W. Eifion Jones

Keyword(s):

Growth Rate ◽

Environmental Factors ◽

High Intensity ◽

Laboratory Experiments ◽

Early Stage ◽

Wave Action ◽

Marine Organisms ◽

Gracilaria Verrucosa ◽

The Church

At an early stage of an autecological study of Gracilaria verrucosa (Hudson) Papenfuss it seemed possible that the best growth of the plants occurred in places, such as the Achill Sound and the Church Island Channel in the Menai Straits, where, in the absence of heavy wave action, strong currents flowed over the plants. Experiments were carried out, in the sea, to investigate the effect of currents on the growth rate; the apparatus used and described here would probably be suitable for the investigation of current effects on other sedentary marine organisms.These experiments also led to some observations on the effects of illumination on the pigmentation and growth rate of the plants which were supplemented by laboratory experiments. High intensity illumination in the laboratory also demonstrated positive phototropism in the plant.

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Modeling and Predicting the Growth Boundary of Listeria monocytogenes in Lightly Preserved Seafood

Journal of Food Protection ◽

10.4315/0362-028x-70.1.70 ◽

2007 ◽

Vol 70 (1) ◽

pp. 70-84 ◽

Cited By ~ 51

Author(s):

OLE MEJLHOLM ◽

PAW DALGAARD

Keyword(s):

Growth Rate ◽

Listeria Monocytogenes ◽

Antimicrobial Effect ◽

Growth Responses ◽

Greenland Halibut ◽

Critical Control Points ◽

Smoked Salmon ◽

Challenge Tests ◽

Boundary Model ◽

Fail Safe

The antimicrobial effect of diacetate and lactate against Listeria monocytogenes was evaluated in challenge tests with vacuum-packaged or modified atmosphere packaged (MAP) cold-smoked salmon, marinated salmon, cold-smoked Greenland halibut, marinated Greenland halibut, and gravad salmon. MAP cold-smoked salmon with the addition of 0.15% (wt/wt) diacetate prevented the growth of L. monocytogenes for more than 40 days at 8°C, whereas the addition of 0.15% (wt/wt) diacetate reduced the growth rate of the pathogen in MAP cold-smoked Greenland halibut. This difference between the two types of products was explained by a higher content of naturally occurring lactate in cold-smoked salmon (0.77 to 0.98%, wt/wt) than in cold-smoked Greenland halibut (0.10 to 0.15%, wt/wt). In fact, the addition of 0.15% (wt/wt) diacetate and 0.75% (wt/wt) lactate to MAP cold-smoked Greenland halibut prevented the growth of L. monocytogenes for more than 45 days at 8°C. A mathematical model that included the effect of diacetate, lactate, CO2, smoke components, nitrite, pH, NaCl, temperature, and interactions between all these parameters was developed to predict the growth boundary of L. monocytogenes in lightly preserved seafood. The developed growth boundary model accurately predicted growth and no-growth responses in 68 of 71 examined experiments from the present study as well as from literature data. Growth was predicted for three batches of naturally contaminated cold-smoked salmon when a no-growth response was actually observed, indicating that the model is fail-safe. The developed model predicts both the growth boundary and growth rate of L. monocytogenes and seems useful for the risk management of lightly preserved seafood. Particularly, the model facilitates the identification of product characteristics required to prevent the growth of L. monocytogenes, thereby making it possible to identify critical control points, and is useful for compliance with the new European Union regulation on ready-to-eat foods (EC 2073/2005).

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Effects of daily handling and other factors on weight gain of mice from birth to six weeks of age

Laboratory Animals ◽

10.1258/002367769781071862 ◽

1969 ◽

Vol 3 (1) ◽

pp. 7-16 ◽

Cited By ~ 3

Author(s):

G. Porter ◽

M. Festing

Keyword(s):

Growth Rate ◽

Weight Gain ◽

Environmental Factors ◽

Environmental Factor ◽

Rapid Growth ◽

Short Term ◽

Rate Of Growth

The results of this experiment show that growth rate in mice is so sensitive to environmental factors that any change in the environment such as handling or diet could cause short-term changes in the rate of growth. It is also shown that if there is a period of restricted growth due to an environmental factor such as either handling or diet, this may be followed by a period of compensating rapid growth.

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Consequences of prenatal and preweaning growth for yield of beef primal cuts from 30-month-old Piedmontese- and Wagyu-sired cattle

Animal Production Science ◽

10.1071/ea08160 ◽

2009 ◽

Vol 49 (6) ◽

pp. 468 ◽

Cited By ~ 17

Author(s):

P. L. Greenwood ◽

L. M. Cafe ◽

H. Hearnshaw ◽

D. W. Hennessy ◽

S. G. Morris

Keyword(s):

Growth Rate ◽

Environmental Factors ◽

Tissue Distribution ◽

Early Life ◽

Low Birthweight ◽

Carcass Weight ◽

Whole Body ◽

Target Market ◽

Subsequent Growth

Cattle sired by Piedmontese or Wagyu bulls were bred and grown within pasture-based nutritional systems followed by feedlot finishing. Effects of low (mean 28.6 kg, n = 120) and high (38.8 kg, n = 120) birthweight followed by slow (mean 554 g/day, n = 119) or rapid (875 g/day, n = 121) growth to weaning on beef primal cut weights at ~30 months of age were examined. Cattle of low birthweight or grown slowly to weaning had smaller primal cuts at 30 months as a result of reduced liveweight and smaller carcasses compared with their high birthweight or rapidly grown counterparts. Hence they require additional nutritional and economic inputs to reach target market weights. At equivalent carcass weights (380 kg), cattle restricted in growth from birth to weaning yielded slightly more beef and were somewhat leaner than their rapidly grown counterparts, resulting in primal cuts being up to 4% heavier in the slowly grown compared with the rapidly grown cattle. Compositional differences due to birthweight were less apparent at the same carcass weight, although low birthweight cattle had a slightly (~2%) heavier forequarter and slightly lower (~1%) hindquarter retail yield, and less shin-shank meat (~2%) than high birthweight cattle, suggesting only minor effects on carcass tissue distribution. There were few interactions between sire genotype and birthweight or preweaning growth, and interactions between birthweight and preweaning growth were not evident for any variables. However, variability between cohorts in their long-term responses to growth early in life suggests other environmental factors during early-life and/or subsequent growth influenced carcass yield characteristics. Overall, this study shows that effects of birthweight and preweaning growth rate on carcass compositional and yield characteristics were mostly explained by variation in carcass weight and, hence, in whole body growth to 30 months of age.

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Synergistic Effects of Sodium Chloride, Glucose, and Temperature on Biofilm Formation by Listeria monocytogenes Serotype 1/2a and 4b Strains

Applied and Environmental Microbiology ◽

10.1128/aem.02185-09 ◽

2010 ◽

Vol 76 (5) ◽

pp. 1433-1441 ◽

Cited By ~ 60

Author(s):

Youwen Pan ◽

Frederick Breidt ◽

Lisa Gorski

Keyword(s):

Growth Rate ◽

Listeria Monocytogenes ◽

Sodium Chloride ◽

Crystal Violet ◽

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Synergistic Effects ◽

Matrix Material ◽

Serotype 1 ◽

Serotype 4B

ABSTRACT Biofilm formation by Listeria monocytogenes is generally associated with its persistence in the food-processing environment. Serotype 1/2a strains make up more than 50% of the total isolates recovered from food and the environment, while serotype 4b strains are most often associated with major outbreaks of human listeriosis. Using a microplate assay with crystal violet staining, we examined biofilm formation by 18 strains of each serotype in tryptic soy broth with varying concentrations of glucose (from 0.25% to 10.0%, wt/vol), sodium chloride (from 0.5% to 7.0%, wt/vol) and ethanol (from 1% to 5.0%, vol/vol), and at different temperatures (22.5Ã¯Â¿Â½C, 30Ã¯Â¿Â½C, and 37Ã¯Â¿Â½C). A synergistic effect on biofilm formation was observed for glucose, sodium chloride, and temperature. The serotype 1/2a strains generally formed higher-density biofilms than the 4b strains under most conditions tested. Interestingly, most serotype 4b strains had a higher growth rate than the 1/2a strains, suggesting that the growth rate may not be directly related to the capacity for biofilm formation. Crystal violet was found to stain both bacterial cells and biofilm matrix material. The enhancement in biofilm formation by environmental factors was apparently due to the production of extracellular polymeric substances instead of the accumulation of viable biofilm cells.

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