scholarly journals Growth potential of Listeria monocytogenes in six different RTE fruit products: impact of food matrix, storage temperature and shelf life

2018 ◽  
Vol 7 (3) ◽  
Author(s):  
Matthias Ziegler ◽  
Simon Rüegg ◽  
Roger Stephan ◽  
Claudia Guldimann
Keyword(s):  
Listeria Monocytogenes ◽  
Shelf Life ◽  
Storage Temperature ◽  
Growth Potential ◽  
Food Matrix ◽  
Significant Growth ◽  
C Storage ◽  
Fresh Cut ◽  
And Storage ◽  
Storage Temperatures

We tested the growth potential of Listeria monocytogenes on six RTE fruit products at low (4°C at the factory followed by 8°C retail/home storage) and abusive (4°C followed by 12°C) storage temperatures. Sliced coconut and fresh cut cantaloupe, as well as a fruit mix containing diced pineapple, cantaloupe, apples and grapes supported the growth of L. monocytogenes with a growth potential d>0.5 log CFU/g over six days. Mangoes, a mix of diced kiwi, cantaloupe and pineapple as well as a mix of diced pineapple, mango, grapefruit, kiwi and pomegranate did not support a growth potential that exceeded 0.5 log CFU/g over six days. The growth potential of L. monocytogenes correlated significantly with the pH; no product with a pH below 4 showed a significant growth potential of L. monocytogenes. Time after inoculation was also a significant predictor of the growth potential, while the fruit type and storage temperature were not.

Effect of Native Microflora, Waiting Period, and Storage Temperature on Listeria monocytogenes Serovars Transferred from Cantaloupe Rind to Fresh-Cut Pieces during Preparation†

2012 ◽  
Vol 75 (11) ◽  
pp. 1912-1919 ◽  
Author(s):  
DIKE O. UKUKU ◽  
MODESTO OLANYA ◽  
DAVID J. GEVEKE ◽  
CHRISTOPHER H. SOMMERS
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Plate Count ◽  
Mesophilic Bacteria ◽  
Recent Outbreak ◽  
Plate Count Method ◽  
Fresh Cut ◽  
Native Microflora ◽  
And Storage ◽  
Storage Temperatures

The most recent outbreak of listeriosis linked to consumption of fresh-cut cantaloupes indicates the need to investigate the behavior of Listeria monocytogenes in the presence of native microflora of cantaloupe pieces during storage. Whole cantaloupes were inoculated with L. monocytogenes (108-CFU/ml suspension) for 10 min and air dried in a biosafety cabinet for 1 h and then treated (unwashed, water washed, and 2.5% hydrogen peroxide washed). Fresh-cut pieces (~3 cm) prepared from these melons were left at 5 and 10°C for 72 h and room temperature (20°C) for 48 h. Some fresh-cut pieces were left at 20°C for 2 and 4 h and then refrigerated at 5°C. Microbial populations of fresh-cut pieces were determined by the plate count method or enrichment method immediately after preparation. Aerobic mesophilic bacteria, yeast and mold of whole melon, and inoculated populations of L. monocytogenes on cantaloupe rind surfaces averaged 6.4, 3.3, and 4.6 log CFU/cm2, respectively. Only H2O2 (2.5%) treatment reduced the aerobic mesophilic bacteria, yeast and mold, and L. monocytogenes populations to 3.8, 0.9, and 1.8 log CFU/cm2, respectively. The populations of L. monocytogenes transferred from melon rinds to fresh-cut pieces were below detection but were present by enrichment. Increased storage temperatures enhanced the lag phases and growth of L. monocytogenes. The results of this study confirmed the need to store fresh-cut cantaloupes at 5°C immediately after preparation to enhance the microbial safety of the fruit.

scholarly journals Growth potential ofListeria monocytogenesin twelve different types of RTE salads: impact of food matrix, storage temperature and shelf life

2018 ◽  
Author(s):  
Matthias Ziegler ◽  
David Kent ◽  
Roger Stephan ◽  
Claudia Guldimann
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Challenge Test ◽  
Growth Characteristics ◽  
Growth Potential ◽  
Food Matrix ◽  
Eu Member States ◽  
Hospitalization Rates ◽  
Food Borne ◽  
And Storage

AbstractListeriosis is a food borne disease associated with high hospitalization and fatality rates; in 2014, EU member states reported 2194 cases with 98.9% hospitalization rates and 210 fatalities. Proper risk analysis and the development of effective food safety strategies critically depend on the knowledge of the growth characteristics ofL. monocytogeneson the product in question. Ready-to-eat (RTE) salads present a challenge in this context due to the absence of a heat treatment step before consumption and the interaction of pathogens with the plant microbial microbiota. This study provides challenge-test based data of the growth characteristics ofL. monocytogeneson twelve RTE salads. The food matrix, storage time and storage temperature were factors with a significant impact on the growth ofL. monocytogenes. While most tested salads permitted a significant increase ofL. monocytogenesin at least one of the tested conditions, no growth was observed on celeriac, carrot and corn salad products. There was a considerable increase in growth at 8 °C compared to 5 °C. Our data indicate that the reduction of the storage temperature at retail level to 5 °C and product shelf life could help mitigate the risk ofL. monocytogenesin RTE salads.

scholarly journals Effect of Potassium Lactate and a Potassium Lactate–Sodium Diacetate Blend on Listeria monocytogenes Growth in Modified Atmosphere Packaged Sliced Ham

2007 ◽  
Vol 70 (10) ◽  
pp. 2297-2305 ◽  
Author(s):  
L. A. MELLEFONT ◽  
T. ROSS
Keyword(s):  
Listeria Monocytogenes ◽  
Organic Acid ◽  
Shelf Life ◽  
Storage Temperature ◽  
Modified Atmosphere ◽  
Acid Salt ◽  
Potassium Lactate ◽  
Sodium Diacetate ◽  
Potential Inhibitors ◽  
And Storage

Two commercially available organic acid salts, potassium lactate (PURASAL HiPure P) and a potassium lactate–sodium diacetate blend (PURASAL Opti.Form PD 4), were assessed as potential inhibitors of Listeria monocytogenes growth in modified atmosphere packaged (MAP) sliced ham in challenge studies. The influence of the initial inoculation level of L. monocytogenes (101 or 103 CFU g−1) and storage temperature (4 or 8°C) was also examined. The addition of either organic acid salt to MAP sliced ham strongly inhibited the growth of L. monocytogenes during the normal shelf life of the product under ideal refrigeration conditions (4°C) and even under abusive temperature conditions (i.e., 8°C). During the challenge studies and in the absence of either organic acid salt, L. monocytogenes numbers increased by 1,000-fold after 20 days at 8°C and 10-fold after 42 days at 4°C. Both organic acid salt treatments were found to be listeriostatic rather than listericidal. The addition of either organic acid salt to the MAP ham also reduced the growth of indigenous microflora, i.e., aerobic microflora and lactic acid bacteria. The influence of these compounds on the risk of listeriosis in relation to product shelf life is discussed.

Quality Characteristics of Vacuum Packaged Beef as Affected by Postmortem Chill, Storage Temperature, and Storage Interval

1976 ◽  
Vol 39 (9) ◽  
pp. 592-599 ◽  
Author(s):  
Z. L. CARPENTER ◽  
S. D. BEEBE ◽  
G. C. SMITH ◽  
K. E. HOKE ◽  
C. VANDERZANT
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Quality Characteristics ◽  
Taste Panel ◽  
Visual Appearance ◽  
Beef Carcasses ◽  
Packaged Beef ◽  
And Storage ◽  
Storage Temperatures

Sirloin butts from beef carcasses chilled to 1 or 7.2 C were vacuum packaged and stored at either 0 or 5.5 C for intervals of 7, 14, 21, 28, or 35 days. Following storage, steaks were obtained for retail caselife studies and taste panel evaluations. Evaluation of primal cuts revealed significant differences in total desirability (primarily visual appearance) among storage intervals and between storage temperatures. Initial carcass temperature at fabrication influenced quality of cuts less than did storage temperature over extended storage intervals. Storage of vacuum packaged cuts at 0 C consistently enhanced shelf-life compared to storage at 5.5 C.

Modeling the Growth of Listeria monocytogenes in Pasteurized White Asparagus

2007 ◽  
Vol 70 (3) ◽  
pp. 753-757 ◽  
Author(s):  
A. VALERO ◽  
E. CARRASCO ◽  
F. PÉREZ-RODRÍGUEZ ◽  
R. M. GARCÍA-GIMENO ◽  
G. ZURERA
Keyword(s):  
Listeria Monocytogenes ◽  
Food Processing ◽  
Goodness Of Fit ◽  
Microbial Population ◽  
Storage Temperature ◽  
Arrhenius Model ◽  
Microbial Risks ◽  
The Relationship ◽  
And Storage ◽  
Storage Temperatures

Growth of Listeria monocytogenes in pasteurized white asparagus was monitored at different storage temperatures (4, 10, 20, and 30°C). Among the main microbial kinetic parameters, growth rate (μ) per hour was calculated at each temperature using the Baranyi-Roberts model. L. monocytogenes was able to grow at all temperatures, although at 4°C only a slight increment of the microbial population was observed (∼1 log CFU/g) after 300 h of storage. Subsequently, two different secondary modeling approaches were proposed to study the relationship between μ and storage temperature: the Arrhenius and Ratkowsky models. Although both models properly described the data observed, smaller values of root mean square error (RMSE) and standard error of prediction (SEP) were obtained with the Ratkowsky model, providing a better goodness of fit (Ratkowsky model: RMSE = 0.010, SEP = 21.23%; Arrhenius model: RMSE = 0.026, SEP = 54.37%). The maximum population density (MPD) was calculated at each temperature studied. A clear dependence between MPD and temperature was found; lower temperatures produced lower values of MPD. This finding confirmed the Jameson effect, indicating that multiple hurdles in the food-processing chain plus lower temperatures reduced L. monocytogenes growth. Predicting the growth of L. monocytogenes along the food chain will help to reduce microbial risks associated with consumption of pasteurized white asparagus.

Effect of Salt, Smoke Compound, and Storage Temperature on the Growth of Listeria monocytogenes in Simulated Smoked Salmon†

2007 ◽  
Vol 70 (10) ◽  
pp. 2321-2328 ◽  
Author(s):  
CHENG-AN HWANG
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Control Measures ◽  
Lag Phase ◽  
Phase Duration ◽  
Liquid Smoke ◽  
Smoked Salmon ◽  
And Storage ◽  
Storage Temperatures ◽  
Maximum Population Density

Smoked salmon can be contaminated with Listeria monocytogenes. It is important to identify the factors that are capable of controlling the growth of L. monocytogenes in smoked salmon so that control measures can be developed. The objective of this study was to determine the effect of salt, a smoke compound, storage temperature, and their interactions on L. monocytogenes in simulated smoked salmon. A six-strain mixture of L. monocytogenes (102 to 103 CFU/g) was inoculated into minced, cooked salmon containing 0 to 10% NaCl and 0 to 0.4% liquid smoke (0 to 34 ppm of phenol), and the samples were stored at temperatures from 0 to 25°C. Lag-phase duration (LPD; hour), growth rate (GR; log CFU per hour), and maximum population density (MPD; log CFU per gram) of L. monocytogenes in salmon, as affected by the concentrations of salt and phenol, storage temperature, and their interactions, were analyzed. Results showed that L. monocytogenes was able to grow in salmon containing the concentrations of salt and phenol commonly found in smoked salmon at the prevailing storage temperatures. The growth of L. monocytogenes was affected significantly (P < 0.05) by salt, phenol, storage temperature, and their interactions. As expected, higher concentrations of salt or lower storage temperatures extended the LPD and reduced the GR. Higher concentrations of phenol extended the LPD of L. monocytogenes, particularly at lower storage temperatures. However, its effect on reducing the GR of L. monocytogenes was observed only at higher salt concentrations (>6%) at refrigerated and mild abuse temperatures (<10°C). The MPD, which generally reached 7 to 8 log CFU/g in salmon that supported L. monocytogenes growth, was not affected by the salt, phenol, and storage temperature. Two models were developed to describe the LPD and GR of L. monocytogenes in salmon containing 0 to 8% salt, 0 to 34 ppm of phenol, and storage temperatures of 4 to 25°C. The data and models obtained from this study would be useful for estimating the behavior of L. monocytogenes in smoked salmon.

Cutting shape, film and storage temperature affect the shelf-life of fresh-cut pumpkin

2018 ◽  
pp. 399-408
Author(s):  
S. Nicola ◽  
G. Tibaldi ◽  
W. Gaino ◽  
G. Pignata
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Fresh Cut ◽  
And Storage

Effect of Mayonnaise pH and Storage Temperature on the Behavior of Listeria monocytogenes in Ham Salad and Potato Salad†

2005 ◽  
Vol 68 (8) ◽  
pp. 1628-1634 ◽  
Author(s):  
CHENG-AN HWANG
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Inactivation Rate ◽  
Consistent Effect ◽  
Cell Counts ◽  
Cooked Ham ◽  
Mathematical Equations ◽  
And Storage ◽  
Storage Temperatures

This study examined and modeled the behavior of Listeria monocytogenes in ham salad and potato salad as affected by the pH of mayonnaise and storage temperature. An eight-strain cocktail of L. monocytogenes was inoculated on the surface of diced cooked ham or potato. The inoculated ham or potato was then mixed with regular mayonnaise (pH 3.8) or mayonnaise that was adjusted with NaOH to pH 4.2 or 4.6. The cell counts of L. monocytogenes in the salads during storage at 4, 8, or 12°C were enumerated and used to model the behavior of L. monocytogenes in ham salad or potato salad. At each of the storage temperatures, L. monocytogenes was able to grow in ham salad, whereas L. monocytogenes was inactivated in potato salad. The growth rate (log CFU per hour) in ham salad or the inactivation rate (log CFU per hour) in potato salad increased as the storage temperature increased. The duration before growth in ham salad or inactivation in potato salad increased as storage temperature decreased. The mayonnaise pH showed no consistent effect on the growth rate or inactivation rate and duration before growth or inactivation occurred. Mathematical equations that described the growth rate or inactivation rate of L. monocytogenes in both salads as a function of mayonnaise pH and storage temperature were generated and shown to be satisfactory in describing the growth rate or inactivation rate of L. monocytogenes in the ham salad or potato salad.

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