Effects of Lactic Acid on the Growth Characteristics of Listeria monocytogenes on Cooked Ham Surfaces†

2012 ◽  
Vol 75 (8) ◽  
pp. 1404-1410 ◽  
Author(s):  
CHENG-AN HWANG ◽  
LIHAN HUANG ◽  
SHIOWSHUH SHEEN ◽  
VIJAY JUNEJA
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Meat Products ◽  
Growth Characteristics ◽  
Lag Phase ◽  
Phase Duration ◽  
Cooked Ham ◽  
Root Model ◽  
Significant Extension

The surfaces of ready-to-eat meats are susceptible to postprocessing contamination by Listeria monocytogenes. This study examined and modeled the growth characteristics of L. monocytogenes on cooked ham treated with lactic acid solutions (LA). Cooked ham was inoculated with L. monocytogenes (ca. 103 CFU/g), immersed in 0, 0.5, 0.75, 1.0, 1.25, 1.5, and 2.0% LA for 30 min, vacuum packaged, and stored at 4, 8, 12, and 16°C. LA immersion resulted in <0.7 log CFU/g immediate reduction of L. monocytogenes on ham surfaces, indicating the immersion alone was not sufficient for reducing L. monocytogenes. During storage, no growth of L. monocytogenes occurred on ham treated with 1.5% LA at 4 and 8°C and with 2% LA at all storage temperatures. LA treatments extended the lag-phase duration (LPD) of L. monocytogenes and reduced the growth rate (GR) from 0.21 log CFU/day in untreated ham to 0.13 to 0.06 log CFU/day on ham treated with 0.5 to 1.25% LA at 4°C, whereas the GR was reduced from 0.57 log CFU/day to 0.40 to 0.12 log CFU/day at 8°C. A significant extension of the LPD and reduction of the GR of L. monocytogenes occurred on ham treated with >1.25% LA. The LPD and GR as a function of LA concentration and storage temperature can be satisfactorily described by a polynomial or expanded square-root model. Results from this study indicate that immersion treatments with >1.5% LA for 30 min may be used to control the growth of L. monocytogenes on cooked meat, and the models would be useful for selecting LA immersion treatments for meat products to achieve desired product safety.

scholarly journals Growth of Listeria monocytogenes in Thawed Frozen Foods

2017 ◽  
Vol 80 (3) ◽  
pp. 447-453 ◽  
Author(s):  
Ai Kataoka ◽  
Hua Wang ◽  
Philip H. Elliott ◽  
Richard C. Whiting ◽  
Melinda M. Hayman
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Growth Rates ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Quadratic Model ◽  
Lag Phase ◽  
Frozen Foods ◽  
Phase Duration ◽  
Primary Model

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.

Competitive Inhibition of Listeria monocytogenes in Ready-to-Eat Meat Products by Lactic Acid Bacteria†

2002 ◽  
Vol 65 (2) ◽  
pp. 316-325 ◽  
Author(s):  
A. AMÉZQUITA ◽  
M. M. BRASHEARS
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Competitive Inhibition ◽  
Meat Products ◽  
16S Rdna Sequence Analysis ◽  
Bacteriocin Producer ◽  
Cooked Ham ◽  
Significant Difference

Forty-nine strains of lactic acid bacteria (LAB), isolated from commercially available ready-to-eat (RTE) meat products, were screened for their ability to inhibit the growth of Listeria monocytogenes at refrigeration (5°C) temperatures on agar spot tests. The three most inhibitory strains were identified as Pediococcus acidilactici, Lactobacillus casei, and Lactobacillus paracasei by 16S rDNA sequence analysis. Their antilisterial activity was quantified in associative cultures in deMan Rogosa Sharpe (MRS) broth at 5°C for 28 days, resulting in a pathogen reduction of 3.5 log10 cycles compared to its initial level. A combined culture of these strains was added to frankfurters and cooked ham coinoculated with L. monocytogenes, vacuum packaged, and stored at 5°C for 28 days. Bacteriostatic activity was observed in cooked ham, whereas bactericidal activity was observed in frankfurters. Numbers of L. monocytogenes were 4.2 to 4.7 log10 and 2.6 log10 cycles lower than controls in frankfurters and cooked ham, respectively, after the 28-day refrigerated storage. In all cases, numbers of LAB increased by only 1 log10 cycle. The strain identified as P. acidilactici was possibly a bacteriocin producer, whereas the antilisterial activity of the other two strains was due to the production of organic acids. There was no significant difference (P > 0.05) in the antilisterial activity detected in frankfurters whether the LAB strains were used individually or as combined cultures. Further studies over a 56-day period indicated no impact on the quality of the product. This method represents a potential antilisterial intervention in RTE meats, because it inhibited the growth of the pathogen at refrigeration temperatures without causing sensory changes.

Influence of Different Histories of the Inoculum on Lag Phase and Growth of Listeria monocytogenes in Meat Models

2006 ◽  
Vol 69 (3) ◽  
pp. 532-541 ◽  
Author(s):  
TOMAS JACOBSEN ◽  
ANETTE GRANLY KOCH
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Salt Concentration ◽  
Biofilm Formation ◽  
Meat Products ◽  
Lag Phase ◽  
Modified Atmosphere ◽  
Phase Duration ◽  
History Of ◽  
Series Of Experiments

The aim of this study was to determine the effect of history of inoculum and preservatives on the lag phase and growth rate of Listeria monocytogenes strains in meat products packaged under modified atmosphere conditions. Inocula with different histories were added to meat models, and growth rate and lag phase of two strains of L. monocytogenes were measured at 5 and 10°C. The meat model stored at 10°C contained sodium lactate, but the model stored at 5°C did not. The five different histories of the inocula included cold propagation, biofilm formation, and starvation. The lag phase ranged from 1 to 10 days and was affected by the history of the inoculum, whereas the growth rate was constant except for one combination of history of inoculum and strain, where growth did not start during the incubation period. In a second series of experiments, the growth rate and lag phase of the two Listeria strains and the effects of two different histories of inoculum were tested in meat models with pH 5.7 or 6.5 and increasing amounts of NaCl. The growth rate depended on salt concentration, bacterial strain, and pH, whereas lag phase duration depended on history of inoculum, salt concentration, and pH. The lag phase duration was highly dependent on the history of the inoculum, and higher amounts of preservative (NaCl) made these effects even more noticeable. The results of this study underline the importance of the effects of the history of the inoculum on lag phase duration and could be used to predict lag phase in industrial meat products.

Control of Listeria monocytogenes on Frankfurters by Dipping in Hops Beta Acids Solutions

2009 ◽  
Vol 72 (4) ◽  
pp. 702-706 ◽  
Author(s):  
CANGLIANG SHEN ◽  
IFIGENIA GEORNARAS ◽  
PATRICIA A. KENDALL ◽  
JOHN N. SOFOS
Keyword(s):  
Listeria Monocytogenes ◽  
Meat Products ◽  
Lag Phase ◽  
Distilled Water ◽  
Department Of Agriculture ◽  
Phase Duration ◽  
Beer Brewing ◽  
Three Samples ◽  
Sensory Qualities ◽  
Inspection Service

Hops beta acids (HBA) are parts of hops flowers used in beer brewing and have shown antilisterial activity in bacteriological broth. The U.S. Department of Agriculture, Food Safety and Inspection Service has approved HBA for use to control Listeria monocytogenes on ready-to-eat meat products. This study evaluated the effects of HBA as dipping solutions to control L. monocytogenes during storage of frankfurters. Frankfurters (two replicates and three samples each) were inoculated (1.9 ± 0.1 log CFU/cm2) with L. monocytogenes (10-strain mixture), dipped (2 min, 25 ± 2°C) in HBA solutions (0.03, 0.06, and 0.10%) or distilled water, and then vacuum packaged and stored at 4 or 10°C for up to 90 and 48 days, respectively. Samples were periodically analyzed for microbial survival and growth on tryptic soy agar plus 0.6% yeast extract and PALCAM agar. Dipping in HBA solutions caused immediate L. monocytogenes reductions (P < 0.05) of 1.3 to 1.6 log CFU/cm2, whereas distilled water reduced counts by 1.0 log CFU/cm2. Pathogen growth was completely suppressed (P < 0.05) for 30 to 50 (4°C) or 20 to 28 (10°C) days on frankfurters dipped in HBA solutions, with antilisterial effects increasing with higher concentrations (0.03 to 0.10%). Fitting the data with the Baranyi model confirmed that the lag-phase duration of the pathogen was extended, and the growth rate was decreased on samples dipped in HBA solutions. Therefore, HBA may be considered for use to improve the microbial safety of ready-to-eat meat products, provided that future studies show no adverse effects on sensory qualities and that their use is economically feasible.

scholarly journals Plant Extracts for the Control of Listeria monocytogenes in Meat Products

2021 ◽  
Vol 11 (22) ◽  
pp. 10820
Author(s):  
Simona de Niederhäusern ◽  
Moreno Bondi ◽  
Stefania Camellini ◽  
Carla Sabia ◽  
Patrizia Messi ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Plant Extracts ◽  
Meat Products ◽  
Antagonistic Activity ◽  
Viable Count ◽  
Lag Phase ◽  
Pathogen Elimination ◽  
Initial Reduction ◽  
Allium Cepa L ◽  
Cooked Ham

The antimicrobial activity of garlic (Allium sativum L.) and onion (Allium cepa L.) plant active extracts was determined against Listeria monocytogenes in two meat products. Samples of sausages “cacciatore” and cooked ham in vacuum-packaged slices were artificially contaminated, and the presence of Listeria was evaluated during the sausages ripening and throughout the shelf-life of the cooked ham. The test carried out on sausages did not show differences among treated and untreated samples. The antagonistic activity of the plant extracts against the pathogen was probably hidden by the competition from the sausages microbial flora and the pH and the water activity (aw) decrease. On the other hand, the plant extracts determined an initial reduction of about 1.00 log cfu/g of the L. monocytogenes viable count in the cooked ham slices contaminated with 103 cfu/g, but the best result was obtained with the contamination of 102 cfu/g of L. monocytogenes. In addition to the pathogen’s initial decrease, we observed an extension of the lag phase and a reduction of the Listeria growth rate. Considering that the presence of L. monocytogenes during the slicing phase of the cooked ham does not exceed 10 cfu/g, the use of plant extracts can lead to complete pathogen elimination.

Control of Listeria monocytogenes on Vacuum-Packaged Frankfurters Sprayed with Lactic Acid Alone or in Combination with Sodium Lauryl Sulfate

2008 ◽  
Vol 71 (4) ◽  
pp. 728-734 ◽  
Author(s):  
OLEKSANDR A. BYELASHOV ◽  
PATRICIA A. KENDALL ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
JOHN N. SOFOS
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Sodium Lauryl Sulfate ◽  
Growth Curves ◽  
Lag Phase ◽  
Lauryl Sulfate ◽  
Phase Duration ◽  
Poultry Products ◽  
All Solutions ◽  
Pathogen Populations

U.S. regulations require that processors employ lethal or inhibitory antimicrobial alternatives in production of ready-toeat meat and poultry products that support growth of Listeria monocytogenes and may be exposed to the processing environment after a lethality treatment. In this study, lactic acid (LA; 5%, vol/vol) and sodium lauryl sulfate (SLS; 0.5%, wt/vol) were evaluated individually or as a mixture (LASLS) for control of L. monocytogenes on frankfurters. Frankfurters were inoculated with a 10-strain mixture of L. monocytogenes, sprayed for 10 s (20 bar, 23 ± 2°C) with antimicrobials or distilled water (DW) before (LASLS or DW) or after (LA, SLS, LASLS, or DW) inoculation (4.8 ± 0.1 log CFU/cm2), vacuum packaged, and stored at 4°C for 90 days. Samples were analyzed for numbers of the pathogen (on PALCAM agar) and for total microbial counts (on tryptic soy agar with yeast extract) during storage. Spraying with DW, LA, or SLS after inoculation reduced numbers of L. monocytogenes by 1.3 ± 0.2, 1.8 ± 0.5, and 2.0 ± 0.4 log CFU/cm2, respectively. The LASLS mixture applied before or after inoculation reduced pathogen populations by 1.8 ± 0.4 and 2.8 ± 0.2 log CFU/cm2, respectively. No further reduction by any treatment was observed during storage. The bacterial growth curves (fitted by the model of Baranyi and Roberts) indicated that the lag-phase duration of the bacterium on control samples (13.85 to 15.18 days) was extended by spraying with all solutions containing LA. For example, LA suppressed growth of L. monocytogenes for 39.14 to 41.01 days. Pathogen growth rates also were lower on frankfurters sprayed after inoculation with LA or LASLS compared to those sprayed with DW. Therefore, spraying frankfurters with a mixture of LA and SLS may be a useful antilisterial alternative treatment for ready-to-eat meat and poultry products.

scholarly journals Listeria monocytogenes Survey in Cubed Cooked Ham Packaged in Modified Atmosphere and Bioprotective Effect of Selected Lactic Acid Bacteria

2020 ◽  
Vol 8 (6) ◽  
pp. 898 ◽  
Author(s):  
Lucilla Iacumin ◽  
Giorgia Cappellari ◽  
Andrea Colautti ◽  
Giuseppe Comi
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Modified Atmosphere Packaging ◽  
Meat Products ◽  
Modified Atmosphere ◽  
Cooked Ham ◽  
Different Temperatures ◽  
Potential Activity ◽  
Cooked Meat ◽  
Cooked Meat Products

The aim of this work was to study the presence of Listeria monocytogenes, as well as the potential activity of two bioprotective cultures (Lyocarni BOX-74 and Lyocarni BOX-57), versus a mix of three L. monocytogenes strains that were intentionally inoculated in cooked cubed ham, packaged in Modified Atmosphere Packaging and stored at different temperatures. The bioprotective cultures limit L. monocytogenes growth in cubed cooked ham stored either at 4 °C for 60 days and at 4 °C for 20 days and at 8 °C for 40 days. The inhibition at 8 °C is particularly useful for industrial cooked meat products, considering there are often thermal abuse conditions (8 °C) in the supermarkets. Both the starters can eliminate L. monocytogenes risk and maintain the products safe, despite the thermal abuse conditions. In addition, both culture starters grew without producing perceptible sensory variations in the samples, as demonstrated by the panel of the untrained tasters. The bioprotective LAB produced neither off-odours and off-flavours, nor white/viscous patinas, slime, discoloration or browning. Therefore, according to the obtained data, and despite the fact that cooked cubed ham did not show pH ≤ 4.4 or aw ≤ 0.92, or pH ≤ 5.0 and aw ≤ 0.94, as cited in the EC Regulation 2073/2005. It can be scientifically stated that cubes of cooked ham with the addition of bioprotective starters cultures do not constitute a favourable substrate for L. monocytogenes growth. Consequently, these products can easily fall into category 1.3 (ready-to-eat foods that are not favourable to L. monocytogenes growth, other than those for infants and for special medical purposes), in which a maximum concentration of L. monocytogenes of 100 CFU g−1 is allowed.

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.

Listeria monocytogenes F2365 Carries Several Authentic Mutations Potentially Leading to Truncated Gene Products, Including InlB, and Demonstrates Atypical Phenotypic Characteristics

2007 ◽  
Vol 70 (2) ◽  
pp. 482-488 ◽  
Author(s):  
K. K. NIGHTINGALE ◽  
S. R. MILILLO ◽  
R. A. IVY ◽  
A. J. HO ◽  
H. F. OLIVER ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Growth Characteristics ◽  
Lag Phase ◽  
Gene Products ◽  
Standard Laboratory ◽  
Phenotypic Characteristics ◽  
Phenotypic Properties ◽  
Phase Duration ◽  
Laboratory Control ◽  
Serotype 4B

Searches of the genome annotation of Listeria monocytogenes F2365, an isolate from the 1985 listeriosis epidemic in California, showed that this strain carries 20 authentic mutations resulting in premature stop codons, including a nonsense mutation in inlB. Here we showed that L. monocytogenes F2365 demonstrates atypical virulence-associated characteristics, including significantly (P < 0.05) reduced invasion efficiency in Caco-2 cells as compared with a closely related lineage I serotype 4b strain as well as significantly (P < 0.05) greater variation in invasiveness when grown under different conditions compared with standard laboratory control and other lineage I serotype 4b strains. In addition, L. monocytogenes F2365 demonstrated distinct growth characteristics, including a significantly (P < 0.05) reduced exponential growth rate when compared with laboratory control and other lineage I serotype 4b outbreak-associated strains as well as a significantly (P < 0.05) longer lag phase duration time compared with another lineage I serotype 4b strain. Our results support that L. monocytogenes F2365 is characterized by genotypic and phenotypic properties that are atypical of other L. monocytogenes strains.

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.

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