scholarly journals Mathematical Modeling for the Growth of Salmonella spp. and Staphylococcus aureus in Cake at Fluctuating Temperatures

2021 ◽  
Vol 11 (6) ◽  
pp. 2475
Author(s):  
Heeyoung Lee ◽  
Jin Hwa Park ◽  
Yu Kyoung Park ◽  
Hyun Jung Kim
Keyword(s):  
Staphylococcus Aureus ◽  
Dynamic Models ◽  
Lag Phase ◽  
Salmonella Spp ◽  
Phase Duration ◽  
Microbial Risk ◽  
Cell Counts ◽  
Different Types ◽  
And Staphylococcus Aureus ◽  
Fluctuating Temperatures

This study aimed to develop dynamic mathematical models to predict the growth of Salmonella spp. and Staphylococcus aureus in a cake under fluctuating temperatures. Among the nine different types of cakes frequently served during school meals, one type of cake was selected based on bacterial growth and water activity. Cocktails of Salmonella spp. and S. aureus were inoculated in the samples and stored at 4–35 °C for up to 336 h. The growth of Salmonella spp. and S. aureus was observed above 20 and 15 °C, respectively. The bacterial cell counts were fitted in the Baranyi model, and the maximum specific growth rate (μmax; log CFU/g/h) and lag phase duration (LPD; h) were analyzed using a polynomial model as a function of temperature (R2 = 0.968–0.988), and the performance of the developed models was appropriate. Furthermore, dynamic models were developed, and the predictions were acceptable in changing the temperature, indicating that the developed dynamic models can successfully predict the outcomes of Salmonella spp. and S. aureus in cake. These results provide useful information for assessing and managing microbial risk in foods by predicting the behavior of Salmonella spp. and S. aureus in cake, especially in changing temperature.

scholarly journals Predictive Modeling for the Growth of Salmonella spp. in Liquid Egg White and Application of Scenario-Based Risk Estimation

2021 ◽  
Vol 9 (3) ◽  
pp. 486
Author(s):  
Mi Seon Kang ◽  
Jin Hwa Park ◽  
Hyun Jung Kim
Keyword(s):  
Predictive Model ◽  
Scenario Analysis ◽  
Specific Growth ◽  
Risk Estimation ◽  
Egg White ◽  
Lag Phase ◽  
Salmonella Spp ◽  
Baseline Model ◽  
Phase Duration ◽  
Root Model

The objective of the study was to develop a predictive model of Salmonella spp. growth in pasteurized liquid egg white (LEW) and to estimate the salmonellosis risk using the baseline model and scenario analysis. Samples were inoculated with six strains of Salmonella, and bacterial growth was observed during storage at 10–37 °C. The primary models were developed using the Baranyi model for LEW. For the secondary models, the obtained specific growth rate (μmax) and lag phase duration were fitted to a square root model and Davey model, respectively, as functions of temperature (R2 ≥ 0.98). For μmax, the values were satisfied within an acceptable range (Af, Bf: 0.70–1.15). The probability of infection (Pinf) due to the consumption of LEW was zero in the baseline model. However, scenario analysis suggested possible salmonellosis for the consumption of LEW. Because Salmonella spp. proliferated much faster in LEW than in egg white (EW) during storage at 20 and 30 °C (p < 0.01), greater Pinf may be obtained for LEW when these products are stored at the same conditions. The developed predictive model can be applied to the risk management of Salmonella spp. along the food chain, including during product storage and distribution.

scholarly journals Food Safety and Food Waste in One Portuguese Public Hospital

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 36
Author(s):  
Carla Gonçalves ◽  
Ana Gomes ◽  
Alexandra Esteves ◽  
José António Silva ◽  
Cristina Maria Saraiva
Keyword(s):  
Staphylococcus Aureus ◽  
Food Safety ◽  
Bacillus Cereus ◽  
Food Waste ◽  
Estimation Method ◽  
Physical Method ◽  
Salmonella Spp ◽  
Hospital Units ◽  
Development Goals ◽  
And Staphylococcus Aureus

The present study aims to contribute to sustainable development goals by increasing knowledge of food safety and food waste of meals produced by the cook–chill system in hospital units. The food waste (FW) of meals served at lunch was evaluated for all new hospitalized patients with light diet (n = 17) and soft texture diet (n = 10), during their hospital stay, using the physical method by weighing for dish and the visual estimation method for the soup. Samples of each diet (light, n = 3; soft texture, n = 3) were also collected in four different moments (after cooked, after cold transportation, after refrigerated storage and after hot regeneration) for detection and enumeration of Listeria monocytogenes, Salmonella spp. and Staphylococcus aureus and enumeration of Escherichia coli, Clostridium spp., Bacillus cereus, Enterobacteriaceae, total viable counts (TVC) at 30 °C, as well as pH, water activity, moisture, ashes and protein. The FW (%) of the light diet (n = 64) was 39.8 ± 6.3 in dish and 14.9 ± 5.4 in soup, and of the soft texture diet (n = 51) was 65.1 ± 9.0 in dish and 39.0 ± 5.8 in soup. Regarding the percentage of protein per meal, both light (8.73%) and soft (3.33%) diets presented on average values lower than those recommended by the WHO (10–15% protein). The value of different microorganisms varied along the production moments; however, the final products in the light diet (after hot regeneration) presented 1.34–1.73 log cfu/g of TVC. Counts of Bacillus cereus and Staphylococcus aureus were also obtained at low levels (less than 1 log cfu/g). Besides these results, the risk of foodborne diseases should be considered. The implementation of effective measures to increase food safety and reduce FW in hospital is crucial.

Viability Loss of Salmonella Species, Staphylococcus aureus, and Listeria monocytogenes in Complex Foods Heated by Microwave Energy

1996 ◽  
Vol 59 (8) ◽  
pp. 813-818 ◽  
Author(s):  
RONALD A. HEDDLESON ◽  
STEPHANIE DOORES ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
GERALD D. KUHN
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Chemical Composition ◽  
Food Systems ◽  
Sodium Content ◽  
Salmonella Spp ◽  
Uht Milk ◽  
Mixed Mean ◽  
Liquid Whole Egg ◽  
And Staphylococcus Aureus

The chemical composition of five foods (UHT milk, beef broth, pudding, cream sauce, and liquid whole egg) was examined to determine factors important in achieving uniform temperatures within foods heated in a 700 W microwave oven. Proximate analyses were performed on all food systems to relate their chemical composition to temperatures and to destruction of microwave-heated Salmonella species, Listeria monocytogenes Scott A and V7 and Staphylococcus aureus ATCC 25923. Microwave heating times were chosen such that the final mixed mean temperature achieved by systems was 60°C for Salmonella spp. and L. monocytogenes, and 65°C for S. aureus. The amount of destruction of Salmonella spp. varied from 3.17 log CFU/ml in UHT milk to 0.44 log CFU/ml in beef broth. L. monocytogenes strains incurred the greatest amount of destruction in pudding (2.39 log CFU/g), while the least amount of destruction was observed in cream sauce (1.63 log CFU/ml). There were no significant differences in the amount of destruction of S. aureus heated in the five foods. The pH and aw of these foods did not affect survival of thermally stressed Salmonella, L. monocytogenes, or S. aureus cells. Of the food components examined, sodium content was the primary influence on the uniformity of temperatures achieved within foods, and, in turn, on the survival of bacteria.

scholarly journals Growth characterisation of Staphylococcus aureus in milk: a quantitative approach

2009 ◽  
Vol 27 (No. 6) ◽  
pp. 433-453 ◽  
Author(s):  
A. Medveďová ◽  
Ľ. Valík ◽  
Z. Sirotná ◽  
D. Liptáková
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Incubation Temperature ◽  
Food Poisoning ◽  
Raw Milk ◽  
Lag Phase ◽  
Phase Duration ◽  
Temperature Range ◽  
Root Model ◽  
Toxigenic Strains

<i>Staphylococcus aureus</i> is a pathogenic bacterium that induces several of human illnesses. The staphylococcal enterotoxin (SE) production as the results of previous growth of toxigenic strains is the most crucial problem which may lead to the staphylococcal food poisoning outbreaks in humans. That is why the growth of three strains of <i>Staphylococcus aureus</i> was characterised in milk and modelled in dependence of temperature. For the lag phase duration of <i>S. aureus</i> 2064, the Davey model was used with the following result: ln(1/lag) = 1.973 – 87.92/<i>T</i> + 285.09/<i>T</i><sup>2</sup> (<i>R</i><sup>2</sup> = 0.962). The dependence of the growth rate on incubation temperature was modelled by the Ratkowsky square root model and Gibson in sub-optimal and whole temperature range, respectively. The validation of both models showed high significance of the growth rate data fitting. The optimal temperature of <i>T</i><sub>opt</sub> = 38.5°C was resulted from Gibson model for the <i>S. aureus</i> 2064 growth in milk. For practical purpose, the time necessary for the increase of <i>S. aureus</i> by 3 log counts was also calculated within the growth temperature range. These data may provide useful information e.g. for the producers using raw milk in their artisanal cheese practice as the specific strains were used in this study.

A dynamic predictive model for the growth of Salmonella spp. and Staphylococcus aureus in fresh egg yolk and scenario-based risk estimation

Food Control ◽  
2020 ◽  
Vol 118 ◽  
pp. 107421 ◽  
Author(s):  
Jin Hwa Park ◽  
Mi Seon Kang ◽  
Kyung Min Park ◽  
Hee Young Lee ◽  
Gyeong Sik Ok ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Predictive Model ◽  
Risk Estimation ◽  
Egg Yolk ◽  
Salmonella Spp ◽  
And Staphylococcus Aureus

Do Cutibacterium acnes and Staphylococcus aureus define two different types of folliculitis?

2018 ◽  
Vol 32 (7) ◽  
pp. e266-e268 ◽  
Author(s):  
C. Frenard ◽  
M-A. Dagnelie ◽  
A. Khammari ◽  
M. Saint-Jean ◽  
A. Boisrobert ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cutibacterium Acnes ◽  
Different Types ◽  
And Staphylococcus Aureus

Growth of Listeria monocytogenes, Salmonella spp., Escherichia coli O157:H7, and Staphylococcus aureus on Cheese during Extended Storage at 25°C

2014 ◽  
Vol 77 (8) ◽  
pp. 1275-1288 ◽  
Author(s):  
WAN MEI LEONG ◽  
RENAE GEIER ◽  
SARAH ENGSTROM ◽  
STEVE INGHAM ◽  
BARBARA INGHAM ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Water Activity ◽  
Titratable Acidity ◽  
Study Data ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Require Time ◽  
And Staphylococcus Aureus

Potentially hazardous foods require time/temperature control for safety. According to the U.S. Food and Drug Administration Food Code, most cheeses are potentially hazardous foods based on pH and water activity, and a product assessment is required to evaluate safety of storage &gt;6 h at 21°C. We tested the ability of 67 market cheeses to support growth of Listeria monocytogenes (LM), Salmonella spp. (SALM), Escherichia coli O157:H7 (EC), and Staphylococcus aureus (SA) over 15 days at 25°C. Hard (Asiago and Cheddar), semi-hard (Colby and Havarti), and soft cheeses (mozzarella and Mexican-style), and reduced-sodium or reduced-fat types were tested. Single-pathogen cocktails were prepared and individually inoculated onto cheese slices (~105 CFU/g). Cocktails were 10 strains of L. monocytogenes, 6 of Salmonella spp., or 5 of E. coli O157:H7 or S. aureus. Inoculated slices were vacuum packaged and stored at 25°C for ≤15 days, with surviving inocula enumerated every 3 days. Percent salt-in-the-moisture phase, percent titratable acidity, pH, water activity, and levels of indigenous/starter bacteria were measured. Pathogens did not grow on 53 cheeses, while 14 cheeses supported growth of SA, 6 of SALM, 4 of LM, and 3 of EC. Of the cheeses supporting pathogen growth, all supported growth of SA, ranging from 0.57 to 3.08 log CFU/g (average 1.70 log CFU/g). Growth of SALM, LM, and EC ranged from 1.01 to 3.02 log CFU/g (average 2.05 log CFU/g), 0.60 to 2.68 log CFU/g (average 1.60 log CFU/g), and 0.41 to 2.90 log CFU/g (average 1.69 log CFU/g), respectively. Pathogen growth varied within cheese types or lots. Pathogen growth was influenced by pH and percent salt-in-the-moisture phase, and these two factors were used to establish growth/no-growth boundary conditions for safe, extended storage (≤25°C) of pasteurized milk cheeses. Pathogen growth/no-growth could not be predicted for Swiss-style cheeses, mold-ripened or bacterial surface–ripened cheeses, and cheeses made with nonbovine milk, as insufficient data were gathered. This challenge study data can support science-based decision making in a regulatory framework.

scholarly journals MICROBIAL CONTAMINATION OF SELECTED FRESH FRUITS AND VEGETABLES SOLD IN HAWASSA, CAPITAL CITY OF SOUTHERN ETHIOPIA

2018 ◽  
Author(s):  
Beyene Dobo
Keyword(s):  
Staphylococcus Aureus ◽  
Fruits And Vegetables ◽  
Good Health ◽  
Total Coliform ◽  
Capital City ◽  
Southern Ethiopia ◽  
Salmonella Spp ◽  
Significant Difference ◽  
Fruit Samples ◽  
And Staphylococcus Aureus

For good health, including fresh fruits and vegetables in our daily diet is very important. Fresh fruits and vegetables are highly perishable and affected by different microbial contaminants from production up to consumption. The objective of this study was to evaluate the important microbial spectrum of selected fruits and vegetables and their management from Hawassa town markets. A total of 27 fruit and 9 vegetable samples were analyzed for pathogens from their surface wash. The mean aerobic mesophillic count (AMC) ranged from 2.04x10-7cfu/ml to 4.2x10-6cfu/ml from the surface wash and the total coliform count (TC) ranged from 2.50LTBccfu/ml x10-7 to 1.5x10-6cfu/ml. Fecal coliform ranged from 3.2x10-6 to 0 cfu/ml and the range for Salmonella spp. and Staphylococcus aureus were 1.8x10-6 to 0 cfu/ml and 2.50LTBcx10-7 to 0 cfu/ml respectively. Mold and yeast count ranged from 7.6x10-6 to 0.2x10-4 from the fruit surface wash. There was statistically significant difference regarding to AMC and TC between markets in between banana and orange samples and they were detected in all fruit samples. From the 36 samples E. coli and molds and yeast were found in all fruit samples, and Salmonella and Staphylococcus aureus were detected in 89% fruit samples in each. Activities during harvesting, transportation, storage and marketing conditions favored contamination of most commonly used fruits banana and orange. Besides, poor hygiene of the venders, using microbial unsafe containers, poor handling practice and poor environmental conditions such as sanitarily unsafe marketing environment were identified to be another sources of contamination. Hence, for safe and clean supply of fruits, community members working with the fruits must be trained on the ways by which fruits can be contaminated and the safe methods of harvesting, transportation, storage and vending the fruits.

Sign in / Sign up

Export Citation Format

Share Document