scholarly journals Spoilage microflora of vacuum packaged frankfurters and influence on the growth of Listeria monocytogenes

2007 ◽  
Vol 23 (5-6-2) ◽  
pp. 103-112 ◽  
Author(s):  
D. Radin ◽  
S.E. Niebuhr ◽  
J.S. Dickson
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Reference Sample ◽  
Aerobic Bacteria ◽  
Lag Phase ◽  
Processed Meat ◽  
Post Processing ◽  
Initial Concentration ◽  
Final Population ◽  
Spoilage Microflora

Spoilage microflora present on vacuum packaged frankfurters is in most cases, result of post processing contamination, at the same time this is the primary cause of contamination with Listeria monocytogenes. Since spoilage organisms are present in the same environment as a pathogen, the aim was to determine their microbial interference. Approximately 100 CFU/cm2 of a five-strain mixture of L. monocytogenes was co inoculated onto frankfurters with different concentrations (103 and 106 CFU/cm2) of spoilage microflora (bacteria from genera Lactobacillus, Bacillus, Micrococcus, and Hafnia). The frankfurters were vacuum packaged and stored at 10?C for up to 48 days. The spoilage microflora that developed during storage consisted predominantly of lactic acid bacteria. The growth of mesophilic aerobic bacteria and LAB was very similar, with populations reaching 8.0 log CFU/cm2 within 24 days and final population of >9 log CFU/cm2 within 48 days. The presence of spoilage microflora extended the lag phase of L. monocytogenes until 24 days and significantly decreased pathogen level to 4 and 3 log CFU/cm2, in samples inoculated with initial concentration 103 CFU/cm2 and 106 CFU/cm2 of spoilage microflora, respectively. L. monocytogenes populations were significantly higher (P<0.05) in the reference sample (no spoilage microflora) and reached a maximum population of 5.9 log CFU/cm2 after 34 days. These results imply that competing microorganisms present on the processed meat may inhibit the growth of L. monocytogenes in the package.

Effect of Antimicrobial Spice and Herb Extract Combinations on Listeria monocytogenes, Staphylococcus aureus, and Spoilage Microflora Growth on Cooked Ready-to-Eat Vacuum-Packaged Shrimp

2011 ◽  
Vol 74 (7) ◽  
pp. 1119-1125 ◽  
Author(s):  
NIMSHA S. WEERAKKODY ◽  
NOLA CAFFIN ◽  
GARY A. DYKES ◽  
MARK S. TURNER
Keyword(s):  
Staphylococcus Aureus ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Lipid Oxidation ◽  
Aerobic Bacteria ◽  
Rosemary Extract ◽  
Spoilage Microflora ◽  
And Staphylococcus Aureus ◽  
Herb Extract

Two spice and herb extract combinations from galangal (Alpinia galanga), rosemary (Rosmarinus officinalis), and lemon iron bark (Eucalyptus staigerana) were evaluated for their ability to inhibit the growth of inoculated Listeria monocytogenes and Staphylococcus aureus and naturally present spoilage microflora on cooked ready-to-eat shrimp stored for 16 days at 4 or 8°C. A combination of galangal, rosemary, and lemon iron bark significantly reduced (P &lt; 0.05) levels of aerobic bacteria and lactic acid bacteria at 4°C on day 12 by 1.6 and 1.59 log CFU/g, respectively. By day 16, levels of these bacteria were equivalent to those of controls. The shrimp treated with this spice and herb extract combination had significantly lower (P &lt; 0.05) lipid oxidation from day 4 to day 16. Similarly, a combination of galangal and rosemary extract significantly reduced (P &lt; 0.05) levels of aerobic bacteria and lactic acid bacteria at 8°C on day 8 by 2.82 and 2.61 log CFU/g, respectively. By days 12 and 16, levels of these bacteria were equivalent to those of controls. The shrimp treated with this spice and herb combination had significantly lower (P &lt; 0.05) lipid oxidation on days 4 and 16. None of the spice and herb extract combinations had an effect on levels of L. monocytogenes or S. aureus or changed the color or pH of the shrimp during storage. The results of this study indicate that combinations of galangal, rosemary, and lemon iron bark extracts can be used to control the growth of spoilage microflora on ready-to-eat shrimp.

Impact of the Population of Spoilage Microflora on the Growth of Listeria monocytogenes on Frankfurters

2006 ◽  
Vol 69 (3) ◽  
pp. 679-681 ◽  
Author(s):  
DRAGOSLAVA RADIN ◽  
STEVEN E. NIEBUHR ◽  
JAMES S. DICKSON
Keyword(s):  
Growth Rate ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Storage Period ◽  
Processed Meat ◽  
Time Intervals ◽  
Mesophilic Bacteria ◽  
Entire Storage Period ◽  
Spoilage Microflora

Approximately 100 CFU/cm2 of a five-strain mixture of Listeria monocytogenes was coinoculated onto frankfurters with three different concentrations (102, 104, and 106 CFU/cm2) of an undefined spoilage microflora derived from commercial frankfurters. The frankfurters were vacuum packaged and stored at 10°C for up to 48 days. The populations of L. monocyto-genes, aerobic mesophilic bacteria, lactic acid bacteria, and Enterobacteriaceae were determined at various time intervals during storage. After 14 days, the population of L. monocytogenes was highest when grown with a spoilage microflora population of 102 CFU/cm2, and this trend continued until 48 days. Throughout the entire storage period, the populations of L. monocytogenes at any concentration of inoculated spoilage microflora rarely differed by more than 0.5 log CFU/cm2, and the maximum observed difference as 1.1 log CFU/cm2 at 40 days. The growth rate of L. monocytogenes was approximately the same at all concentrations of the inoculated spoilage microflora. These results suggest that the concentration of spoilage microflora present on the original processed meat may have a slight impact on the growth of L. monocytogenes in the package.

Effect of Single or Sequential Hot Water and Lactic Acid Decontamination Treatments on the Survival and Growth of Listeria monocytogenes and Spoilage Microflora during Aerobic Storage of Fresh Beef at 4, 10, and 25°C

2004 ◽  
Vol 67 (12) ◽  
pp. 2703-2711 ◽  
Author(s):  
KONSTANTINOS P. KOUTSOUMANIS ◽  
LAURA V. ASHTON ◽  
IFIGENIA GEORNARAS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Hot Water ◽  
Microbial Profile ◽  
Spoilage Bacteria ◽  
Brochothrix Thermosphacta ◽  
Survival And Growth ◽  
Spoilage Microflora ◽  
Storage Temperatures

The survival and growth of Listeria monocytogenes and spoilage microflora during storage of fresh beef subjected to different decontamination treatments was studied. Fresh beef inoculated with a five-strain mixture of L. monocytogenes (5.18 log CFU/cm2) was left untreated (control) or was immersed (30 s) in hot water (HW; 75°C), 2% lactic acid (LA; 55°C), hot water followed by lactic acid (HW-LA), or lactic acid followed by hot water (LA-HW) and then stored aerobically at 4, 10, and 25°C for 25, 17, and 5 days, respectively. Initial populations of L. monocytogenes were reduced by 0.82 (HW), 1.43 (LA), 2.73 (HW-LA), and 2.68 (LA-HW) log CFU/cm2. During storage, the pathogen grew at higher rates in HW than in control samples at all storage temperatures. Acid decontamination treatments (LA, HW-LA, and LA-HW) resulted in a weaker inhibition of L. monocytogenes (P &lt; 0.05) at 25°C than at 4 and 10°C. In general, the order of effectiveness of treatments was HW-LA &gt; LA &gt; LA-HW &gt; HW &gt; control at all storage temperatures tested. In untreated samples, the spoilage microflora was dominated by pseudomonads, while lactic acid bacteria, Enterobacteriaceae, and yeasts remained at lower concentrations during storage. Brochothrix thermosphacta was detected periodically in only a limited number of samples. Although decontamination with HW did not affect the above spoilage microbial profile, acid treatments shifted the predominant microflora in the direction of yeasts and gram-positive bacteria (lactic acid bacteria). Overall, the results of the present study indicate that decontamination with LA and combinations of LA and HW could limit growth of L. monocytogenes and inhibit pseudomonads, which are the main spoilage bacteria of fresh beef stored under aerobic conditions. However, to optimize the efficacy of such treatments, they must be applied in the appropriate sequence and followed by effective temperature control.

Postprocess Control of Listeria monocytogenes on Commercial Frankfurters Formulated with and without Antimicrobials and Stored at 10°C

2006 ◽  
Vol 69 (1) ◽  
pp. 53-61 ◽  
Author(s):  
IFIGENIA GEORNARAS ◽  
PANAGIOTIS N. SKANDAMIS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
PATRICIA A. KENDALL ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Lag Phase ◽  
Potassium Lactate ◽  
Potassium Benzoate ◽  
Sodium Diacetate ◽  
Specific Growth Rates ◽  
Spoilage Microflora ◽  
Antimicrobial Treatments ◽  
Microbiological Analyses ◽  
Different Sources

The antilisterial effect of postprocess antimicrobial treatments on commercially manufactured frankfurters formulated with and without a 1.5% potassium lactate–0.05% sodium diacetate combination was evaluated. Frankfurters were inoculated (ca. 3 to 4 log CFU/cm2) with 10-strain composite Listeria monocytogenes cultures originating from different sources. The inocula evaluated were cells grown planktonically in tryptic soy broth plus 0.6% yeast extract (30°C, 24 h) or in a smoked sausage homogenate (15°C, 7 days) and cells that had been removed from stainless steel coupons immersed in an inoculated smoked sausage homogenate (15°C, 7 days). Inoculated frankfurters were dipped (2 min, 25 ± 2°C) in acetic acid (AA; 2.5%), lactic acid (LA; 2.5%), potassium benzoate (PB; 5%), or Nisaplin (commercial form of nisin; 0.5%, equivalent to 5,000 IU/ml of nisin) solutions, or in Nisaplin followed by AA, LA, or PB, and were subsequently vacuum packaged and stored for 48 days at 10°C. In addition to microbiological analyses, sensory evaluations were performed with uninoculated samples that had been treated with AA, LA, or PB for 2 min. Initial L. monocytogenes populations were reduced by 1.0 to 1.8 log CFU/cm2 following treatment with AA, LA, or PB solutions, and treatments that included Nisaplin reduced initial levels by 2.4 to &gt;3.8 log CFU/cm2. All postprocessing treatments resulted in some inhibition of L. monocytogenes during the initial stages of storage of frankfurters that were not formulated with potassium lactate–sodium diacetate; however, in all cases, significant (P &lt; 0.05) growth occurred by the end of storage. The dipping of products formulated with potassium lactate–sodium diacetate in AA or LA alone—or in Nisaplin followed by AA, LA, or PB—increased lag-phase durations and lowered the maximum specific growth rates of the pathogen. Moreover, depending on the origin of the inoculum, this dipping of products led to listericidal effects. In general, differences in growth kinetics were obtained for the three inocula that were used to contaminate the frankfurters. Possible reasons for these differences include the presence of stress-adapted subpopulations and the inhibition of the growth of the pathogen due to high levels of spoilage microflora. The dipping of frankfurters in AA, LA, or PB did not (P &gt; 0.05) affect the sensory attributes of the product when compared to the control samples. The data generated in this study may be useful to U.S. ready-to-eat meat processors in their efforts to comply with regulatory requirements.

scholarly journals Growth potential of Listeria monocytogenes in veal tartare

2021 ◽  
Vol 10 (3) ◽  
Author(s):  
Simone Stella ◽  
Cristian Bernardi ◽  
Erica Tirloni
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Challenge Test ◽  
Growth Potential ◽  
Daily Maximum ◽  
Initial Concentration ◽  
Spoilage Bacteria ◽  
Sampling Times

In the present study the growth potential of Listeria monocytogenes in veal tartare was evaluated. A challenge test was performed on three tartare batches at 8°C, aiming to evaluate the growth potential of the pathogen. The data indicated the absence of a significant growth (δ<0.5 log cfu/g) during the entire period. When considering intermediate sampling times, an increase of 0.56 log cfu/g was detected after five days of storage in one of the batches. Microflora of veal tartare was dominated by lactic acid bacteria, that increased gradually during the trial, reaching counts up to 7 Log CFU/g in two of the three batches considered. Spoilage bacteria were present (especially Pseudomonas spp., yeasts and Enterobacteriaceae) but in very low counts and with a limited increase during the period considered. Finally, daily maximum tolerable L. monocytogenes counts were calculated to highlight the maximum acceptable load to avoid the overcoming of the legal limit of 100 CFU/g: a total increase of 0.95 log cfu/g in 12 days of shelf-life was estimated, obtaining a “safety initial concentration” at t0 of 10 CFU/g of the pathogen.

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 &lt;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 &gt;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 &gt;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.

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.

Growth of Listeria monocytogenes in a Model High-Moisture Cheese on the Basis of pH, Moisture, and Acid Type

2020 ◽  
Vol 83 (8) ◽  
pp. 1335-1344
Author(s):  
SARAH K. ENGSTROM ◽  
CHRISTIE CHENG ◽  
DENNIS SEMAN ◽  
KATHLEEN A. GLASS
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Citric Acid ◽  
Ph Value ◽  
Growth Parameters ◽  
Growth Curves ◽  
Lag Phase ◽  
High Moisture ◽  
Contrast Model ◽  
Acid Type

ABSTRACT High-moisture, low-acid cheeses have been shown to support Listeria monocytogenes growth during refrigerated storage. Prior studies suggest that organic acids vary in their antilisterial activity and that cheeses of lower pH delay growth longer than those of higher pH; however, no standard pH value for Listeria control in cheese exists. The objective of this research was to create a predictive model to include the effects of acid type, pH, and moisture on the growth of L. monocytogenes in a model cheese system. Cream, micellar casein, water, lactose, salt, and acid (citric, lactic, acetic, or propionic) were combined in 32 formulations targeting 4 pH values (5.25, 5.50, 5.75, and 6.00) and two moisture levels (50 and 56%). Each was inoculated with 3 log CFU/g L. monocytogenes (five-strain mixture) after which 25-g samples were vacuum sealed and stored 8 weeks at 4°C. Triplicate samples were enumerated on modified Oxford agar weekly in duplicate trials. Model cheeses formulated with acetic and propionic acids inhibited growth (i.e., no observed increase in L. monocytogenes populations over 8 weeks) at pH ≤5.75, while those formulated with lactic acid inhibited growth at pH 5.25 only. In contrast, all model cheeses formulated with citric acid supported growth. Resulting growth curves were fitted for lag phase and growth rate before constructing models for each. The pH and acid type were found to significantly affect both growth parameters (P &lt; 0.05), while moisture (50 to 56%) was not statistically significant in either model (P ≥ 0.05). The effects of acetic and propionic acid were not significantly different. In contrast, model cheeses made with citric acid had significantly shorter lag phases than the other acids tested, but growth rates after lag were statistically similar to model cheeses made with lactic acid. These data suggest propionic ∼ acetic &gt; lactic &gt; citric acids in antilisterial activity within the model cheese system developed and can be used in formulating safe high-moisture cheeses. HIGHLIGHTS

Combined Effects of Packaging Atmosphere and Lactic Acid on Growth and Survival of Listeria monocytogenes in Crayfish Tail Meat at 4°C

1996 ◽  
Vol 59 (3) ◽  
pp. 253-256 ◽  
Author(s):  
PRASAD POTHURI ◽  
DOUGLAS L. MARSHALL ◽  
KENNETH W. McMILLIN
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Modified Atmosphere Packaging ◽  
Vacuum Packaging ◽  
Lag Phase ◽  
Modified Atmosphere ◽  
Combined Effects ◽  
Growth And Survival ◽  
Microbial Counts ◽  
Colony Forming Units

The effect of lactic acid on growth and survival of Listeria monocytogenes in crayfish tail meat stored under refrigeration and various gas environments was investigated. Frozen crayfish tail meat was thawed overnight, autoclaved, cooled, and inoculated with approximately 4 log colony-forming units (CFU) of a mixed-strain (Scott A and F5027) L. monocytogenes culture per gram of meat. Inoculated samples were blended with 0, 0.5, 1.0, 1.5, or 2.0% lactic acid and packaged under air, vacuum, or modified atmosphere (74.8% CO2, 10.4% O2, and 14.8% N2) and stored at 4°C for 20 days. Results demonstrated that modified atmosphere packaging inhibited the growth of L. monocytogenes more than air and vacuum packaging at 0 and 1% lactic acid. Microbial counts declined steadily in crayfish tail meat treated with 2% lactic acid, with no differences among the packaging atmospheres. The lag phase was extended by 8 days in samples treated with 1% lactic acid and modified atmosphere compared to that in air or vacuum packaging. Overall, the combination of lactic acid and modified atmosphere had the greatest potential to prevent growth of L. monocytogenes.

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