Survival of Salmonella enterica Serotype Tennessee during Simulated Gastric Passage Is Improved by Low Water Activity and High Fat Content

2013 ◽  
Vol 76 (2) ◽  
pp. 333-337 ◽  
Author(s):  
BRYAN AVILES ◽  
COURTNEY KLOTZ ◽  
TWYLA SMITH ◽  
ROBERT WILLIAMS ◽  
MONICA PONDER
Keyword(s):  
Water Activity ◽  
Salmonella Enterica ◽  
Peanut Butter ◽  
Gastric Fluid ◽  
Fat Content ◽  
Simulated Gastric Fluid ◽  
Food Matrix ◽  
High Fat ◽  
Low Fat ◽  
Infectious Dose

The low water activity (aw 0.3) of peanut butter prohibits the growth of Salmonella in a product; however, illnesses are reported from peanut butter contaminated with very small doses, suggesting the food matrix itself influences the infectious dose of Salmonella, potentially by improving Salmonella's survival in the gastrointestinal tract. The purpose of our study was to quantify the survival of a peanut butter outbreak–associated strain of Salmonella enterica serotype Tennessee when inoculated into peanut butters with different fat contents and aw (high fat, high aw; high fat, low aw; low fat, high aw; low fat, low aw) and then challenged with a simulated gastrointestinal system. Exposures to increased fat content and decreased aw both were associated with a protective effect on the survival of Salmonella Tennessee in the simulated gastric fluid compared with control cells. After a simulated intestinal phase, the populations of Salmonella Tennessee in the control and low-fat formulations were not significantly different; however, a 2-log CFU/g increase occurred in high-fat formulations. This study demonstrates that cross-protection from low-aw stress and the presence of high fat results in improved survival in the low pH of the stomach. The potential for interaction of food matrix and stress adaptations could influence the virulence of Salmonella and should be considered for risk analysis.

Heat Tolerance of Salmonella enterica Serovars Agona, Enteritidis, and Typhimurium in Peanut Butter

2006 ◽  
Vol 69 (11) ◽  
pp. 2687-2691 ◽  
Author(s):  
DINA SHACHAR ◽  
SIMA YARON
Keyword(s):  
Water Activity ◽  
Heat Tolerance ◽  
Salmonella Enterica ◽  
Thermal Inactivation ◽  
Colloidal Suspension ◽  
Peanut Butter ◽  
Peanut Meal ◽  
Cell Number ◽  
Fat Content ◽  
Lower Probability

Recent large foodborne outbreaks caused by Salmonella enterica serovars have been associated with consumption of foods with high fat content and reduced water activity, even though their ingredients usually undergo pasteurization. The present study was focused on the heat tolerance of Salmonella enterica serovars Agona, Enteritidis, and Typhimurium in peanut butter. The Salmonella serovars in the peanut butter were resistant to heat, and even at a temperature as high as 90°C only 3.2-log reduction in CFU was observed. The obtained thermal inactivation curves were upwardly concave, indicating rapid death at the beginning (10 min) followed by lower death rates and an asymptotic tail. The curves fitted the nonlinear Weibull model with β parameters <1, indicating that the remaining cells have a lower probability of dying. β at 70°C (0.40 ± 0.04) was significantly lower than β at 80°C (0.73 ± 0.19) and 90°C (0.69 ± 0.17). Very little decrease in the viable population (less than 2-log decrease) was noted in cultures that were exposed to a second thermal treatment. Peanut butter is a highly concentrated colloidal suspension of lipid and water in a peanut meal phase. We hypothesized that differences in the local environments of the bacteria, with respect to fat content or water activity, explained the observed distribution and high portion of surviving cells (0.1%, independent of the initial cell number). These results demonstrate that thermal treatments are inadequate to consistently destroy Salmonella in highly contaminated peanut butter and that the pasteurization process cannot be improved significantly by longer treatment or higher temperatures.

Experimental obesity and osteoarthritis

1960 ◽  
Vol 198 (4) ◽  
pp. 765-770 ◽  
Author(s):  
Leon Sokoloff ◽  
Olaf Mickelsen ◽  
Emanuel Silverstein ◽  
George E. Jay ◽  
Richard S. Yamamoto
Keyword(s):  
Weight Gain ◽  
Dietary Restriction ◽  
High Fat Diet ◽  
Deleterious Effect ◽  
Degenerative Joint Disease ◽  
Fat Content ◽  
Joint Disease ◽  
High Fat ◽  
Low Fat ◽  
Hybrid Mice

Experimental obesity was produced in DBA/2JN, STR/N and C57L/HeN mice as well as in Osborne-Mendel rats by several dietary regimens. One of these, containing 60% vegetable fat, increased the amount of degenerative joint disease in the rats and in two strains of mice. No increase of osteoarthritis occurred as a result of a 37.4% fat content in the diet, or from obesity produced by Ingle's diet, which has a relatively low-fat content. The mechanism by which the high-fat diet increased the joint disease is unknown, because neither obesity nor a high-fat diet alone had a deleterious effect on the articulations of the mice. Obese hybrid mice derived from a spontaneously obese and arthritis-prone strain (STR/1N) were resistant to articular degeneration. Dietary restriction of weight gain in the STR/1N mice failed to decrease the osteoarthritis in them.

scholarly journals Effects of Dietary Protein and Fat Content on Intrahepatocellular and Intramyocellular Lipids during a 6-Day Hypercaloric, High Sucrose Diet: A Randomized Controlled Trial in Normal Weight Healthy Subjects

Nutrients ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 209 ◽  
Author(s):  
Anna Surowska ◽  
Prasanthi Jegatheesan ◽  
Vanessa Campos ◽  
Anne-Sophie Marques ◽  
Léonie Egli ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Fat Content ◽  
High Protein ◽  
Resonance Spectroscopy ◽  
High Fat ◽  
Low Fat ◽  
Low Protein ◽  
Sucrose Diet ◽  
High Sucrose Diet ◽  
High Sucrose

Sucrose overfeeding increases intrahepatocellular (IHCL) and intramyocellular (IMCL) lipid concentrations in healthy subjects. We hypothesized that these effects would be modulated by diet protein/fat content. Twelve healthy men and women were studied on two occasions in a randomized, cross-over trial. On each occasion, they received a 3-day 12% protein weight maintenance diet (WM) followed by a 6-day hypercaloric high sucrose diet (150% energy requirements). On one occasion the hypercaloric diet contained 5% protein and 25% fat (low protein-high fat, LP-HF), on the other occasion it contained 20% protein and 10% fat (high protein-low fat, HP-LF). IHCL and IMCL concentrations (magnetic resonance spectroscopy) and energy expenditure (indirect calorimetry) were measured after WM, and again after HP-LF/LP-HF. IHCL increased from 25.0 ± 3.6 after WM to 147.1 ± 26.9 mmol/kg wet weight (ww) after LP-HF and from 30.3 ± 7.7 to 57.8 ± 14.8 after HP-LF (two-way ANOVA with interaction: p < 0.001 overfeeding x protein/fat content). IMCL increased from 7.1 ± 0.6 to 8.8 ± 0.7 mmol/kg ww after LP-HF and from 6.2 ± 0.6 to 6.9 ± 0.6 after HP-LF, (p < 0.002). These results indicate that liver and muscle fat deposition is enhanced when sucrose overfeeding is associated with a low protein, high fat diet compared to a high protein, low fat diet.

Modification of a Predictive Model To Include the Influence of Fat Content on Salmonella Inactivation in Low-Water-Activity Foods

2020 ◽  
Vol 83 (5) ◽  
pp. 801-815
Author(s):  
LISA M. TRIMBLE ◽  
JOSEPH F. FRANK ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Water Activity ◽  
Survival Data ◽  
Peanut Butter ◽  
Weibull Model ◽  
Fat Content ◽  
Mitigation Strategies ◽  
Model Parameters ◽  
Least Squares Regression ◽  
Salmonella Spp ◽  
Model Predictions

ABSTRACT Low-water-activity (aw) foods (including those containing fat) are often implicated in outbreaks of Salmonella spp. The influence of fat content on survival in foods such as peanut butter remains unclear. Certain Salmonella serovars can survive for long periods in harsh temperatures and low moisture conditions. The objective of this study was to determine the influence of fat content on the survival of Salmonella in low-aw foods and expand an existing secondary inactivation model previously validated for lower-fat foods. Whey protein powder supplemented with peanut oil was equilibrated to five target aw values (aw &lt; 0.60), inoculated with a dried four-strain cocktail of Salmonella, vacuum sealed, and stored at 22, 37, 50, 60, 70, and 80°C for 48 h, 28 days, or 168 days. Survival data were fitted to Weibull, Biphasic-linear, Double Weibull, and Geeraerd-tail models. The Weibull model was chosen for secondary modeling due to its ability to satisfactorily describe the data over most of the conditions under study. The influence of temperature, fat content, and aw on the Weibull model parameters was evaluated using nonlinear least squares regression, and a revised secondary model was developed based on parameter significance. Peanut butter, chia seed powder, toasted oat cereal, and animal crackers within the aw range of the model were used to validate the modified model within its temperature range. Fat content influenced survival in samples held at temperatures ≥50°C, whereas aw influenced survival at 37 and 70°C. The model predictions demonstrated improved % bias and % discrepancy compared with the previous model. Weibull model predictions were accurate and fail-safe in 38 and 58%, respectively, of the food and environmental conditions under study. Predictions were less reliable for peanut butter held at 80°C. This study provides data and a model that can aid in the development of risk mitigation strategies for low-aw foods containing fat. HIGHLIGHTS

An Analysis of Variation of Insecticide Residues in Landlocked Atlantic Salmon (Salmo salar)

1970 ◽  
Vol 27 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Richard B. Anderson ◽  
Owen C. Fenderson
Keyword(s):  
Sampling Methods ◽  
Fat Content ◽  
High Fat ◽  
Low Fat ◽  
Insecticide Residues ◽  
Insecticide Content ◽  
Good Body Condition ◽  
Spawning Run ◽  
Analysis Of Variation ◽  
Selection Of

High variation in yearly samples of insecticide residues found in landlocked salmon from Sebago Lake, Maine, has necessitated an evaluation of sampling methods and an investigation of causes of variation. A sample of 59 male salmon, composed of ages III+, IV+, and V+, and representing fish in poor and good body condition was collected from a spawning run in the fall of 1967 and analyzed for DDT, DDD, DDE, dieldrin, and fat content. Levels of insecticide residues were found to be highly dependent on age and fat content. DDD and DDE increased with age and fat content, and dieldrin increased with fat content. Age and fat content were interdependent in their effects on DDT levels. DDT was significantly higher in high-fat than in low-fat fish at ages III+ and IV+ but not at age V+, showing a decrease with age among fish with high fat content and remaining constant with age among fish with low fat content. It is recommended that completely random selection of fish for insecticide analyses be abandoned in favor of stratification by sex, age, and fatness. Some of the possible causes of variation in insecticide content of salmon are discussed.

scholarly journals The absorption of vitamin E is influenced by the amount of fat in a meal and the food matrix

2004 ◽  
Vol 92 (4) ◽  
pp. 575-579 ◽  
Author(s):  
Yvonne M. Jeanes ◽  
Wendy L. Hall ◽  
Susan Ellard ◽  
Elizabeth Lee ◽  
John K. Lodge
Keyword(s):  
Vitamin E ◽  
Intervention Studies ◽  
Tocopheryl Acetate ◽  
Limited Information ◽  
Healthy Individuals ◽  
Food Matrix ◽  
High Fat ◽  
Low Fat ◽  
Tocopherol Concentration ◽  
Skimmed Milk

Vitamin E absorption requires the presence of fat; however, limited information exists on the influence of fat quantity on optimal absorption. In the present study we compared the absorption of stable-isotope-labelled vitamin E following meals of varying fat content and source. In a randomised four-way cross-over study, eight healthy individuals consumed a capsule containing 150 mg 2H-labelled RRR-α-tocopheryl acetate with a test meal of toast with butter (17·5 g fat), cereal with full-fat milk (17·5 g fat), cereal with semi-skimmed milk (2·7 g fat) and water (0 g fat). Blood was taken at 0, 0·5, 1, 1·5, 2, 3, 6 and 9 h following ingestion, chylomicrons were isolated, and 2H-labelled α-tocopherol was analysed in the chylomicron and plasma samples. There was a significant time (P<0·001) and treatment effect (P<0·001) in 2H-labelled α-tocopherol concentration in both chylomicrons and plasma between the test meals. 2H-labelled α-tocopherol concentration was significantly greater with the higher-fat toast and butter meal compared with the low-fat cereal meal or water (P<0·001), and a trend towards greater concentration compared with the high-fat cereal meal (P=0·065). There was significantly greater 2H-labelled α-tocopherol concentration with the high-fat cereal meal compared with the low-fat cereal meal (P<0·05). The 2H-labelled α-tocopherol concentration following either the low-fat cereal meal or water was low. These results demonstrate that both the amount of fat and the food matrix influence vitamin E absorption. These factors should be considered by consumers and for future vitamin E intervention studies.

scholarly journals Increased Water Activity Reduces the Thermal Resistance of Salmonella enterica in Peanut Butter

2013 ◽  
Vol 79 (15) ◽  
pp. 4763-4767 ◽  
Author(s):  
Yingshu He ◽  
Ye Li ◽  
Joelle K. Salazar ◽  
Jingyun Yang ◽  
Mary Lou Tortorello ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Resistance ◽  
Water Activity ◽  
Salmonella Enterica ◽  
Morphological Changes ◽  
Peanut Butter ◽  
Content Type ◽  
The Difference ◽  
Scanning Electron

ABSTRACTIncreased water activity in peanut butter significantly (P< 0.05) reduced the heat resistance of desiccation-stressedSalmonella entericaserotypes treated at 90°C. The difference in thermal resistance was less notable when strains were treated at 126°C. Using scanning electron microscopy, we observed minor morphological changes ofS. entericacells resulting from desiccation and rehydration processes in peanut oil.

scholarly journals Liking and Acceptability of Whole Grains Increases with a 6-Week Exposure but Preferences for Foods Varying in Taste and Fat Content Are Not Altered: A Randomized Controlled Trial

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Angela De Leon ◽  
Dustin J Burnett ◽  
Bret M Rust ◽  
Shanon L Casperson ◽  
William F Horn ◽  
...  
Keyword(s):  
Controlled Trial ◽  
Health Benefits ◽  
Sweet Taste ◽  
Fat Content ◽  
Whole Grains ◽  
Mere Exposure ◽  
Dietary Guidelines ◽  
High Fat ◽  
Low Fat ◽  
Grain Products

ABSTRACT Background Since 2005, the Dietary Guidelines for Americans have recommended consuming at least half of total grains as whole grains (WGs) for optimal health benefits; however, consumption of WGs falls far short of recommended amounts. Objective This study aimed to evaluate the effect of mere exposure to WGs on liking, acceptability, and consumption of WG foods and to determine if exposure to WG would influence liking and wanting for other foods varying in fat content and sweet taste. Methods Healthy, self-identified low WG consumers (n = 45) were randomly assigned to either a 6-wk WG intervention or a refined grain (RG) control condition during which they received a weekly market basket of grain products to incorporate into daily meals and snacks. Consumption of grain products was measured by weekly logs and weigh-backs. A sensory evaluation protocol was conducted at baseline and week 6 to evaluate changes in perception of grain products. Computer tasks designed to measure liking and wanting for other foods varying in high/low-fat content and sweet/savory taste were also completed at baseline and week 6. Results Participants in the WG group significantly increased WG consumption. Exposure to WG products resulted in improved ratings of liking, flavor, texture, and willingness to include WG in the regular diet. No significant changes in liking or wanting for foods representing high-fat sweet (HFSW), low-fat sweet (LFSW), high-fat savory (HFSA), or low-fat savory (LFSA) categories were found in the WG group. In contrast, exposure to RG foods resulted in an increased explicit wanting for HFSW and LFSW and a decreased wanting for HFSA foods. Conclusions Mere exposure to WG foods represents a feasible and easily applied behavioral strategy for increasing consumption of WGs. Encouraging consumers to focus on enjoyment of the taste may be more effective than emphasizing the health benefits of WG consumption. This trial was registered at clinicaltrials.gov as NCT01403857.

Moisture Transmission Through Peanut Oil Films

1974 ◽  
Vol 1 (2) ◽  
pp. 47-50 ◽  
Author(s):  
Peter J. Tiemstra ◽  
John P. Tiemstra
Keyword(s):  
Film Thickness ◽  
Water Activity ◽  
Moisture Transfer ◽  
Transmission Rate ◽  
Peanut Butter ◽  
Fat Content ◽  
Peanut Oil ◽  
Activity Phase ◽  
The Difference ◽  
Oil Films

Abstract The rate of moisture transfer through a peanut oil film was measured. It was found that the rate can be expressed by the equation: r = [k a1 (Δ a)]/t where r is the rate in g water/cm2/day, a1 is the higher water activity, Δ a is the difference in the water activity across the barrier, t is the film thickness and k is a constant. This principle was extended to fat-humectant systems where the lower water activity phase is intimately distributed through the fatty medium such as peanut butter and chocolate liquor. Doubling the fat content should increase the film thickness around each particle by 2 and halve the transmission rate as was found experimentally.

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