Modeling microbial competition in food: Application to the behavior of Listeria monocytogenes and lactic acid flora in pork meat products

AbstractPhysicochemical and microbiological properties of pork chops sprayed with Neutral Electrolyzed Water (NEW) were evaluated during storage at refrigeration temperature. Pork chops were randomly allocated into three groups and were artificially contaminated with an inoculum of 106 CFU/mL of Listeria monocytogenes. Each group was treated with either NEW (58 ppm), NaClO (35 ppm), or saline solution (SS). Subsequently, recovered bacteria were plated on TSA petri dishes and the reduction percentage of Listeria monocytogenes was calculated 24 h and 8 days after treatment. Physicochemical analysis [pH, content of lactic acid, thiobarbituric acid reactive substances (TBARS) and total volatile base nitrogen (TVBN)] were performed to evaluate the effect of all solutions used on pork meat kept at 4 °C for 19 days. In vitro NEW reduced L. monocytogenes titers by > 99.98% and 80.19% and 90.35% in artificially contaminated pork 24 h and 8 days after NEW treatment, respectively. Compared to the SS treatment, NEW and NaClO solutions caused a 0.67 Log UFC/g and 0.65 Log UFC/g reduction respectively. After eight days post-treatment, NEW and NaClO bacterial titers were below the SS treatment. NEW caused little color change in treated meat. It helped to reduce the formation of lactic acid and TVB-N when pork chops are kept at 4 °C for 19 days. Therefore, NEW could be considered as a new alternative to sanitize and preserve pork meat.

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Use of UV Light for the Inactivation of Listeria monocytogenes and Lactic Acid Bacteria Species in Recirculated Chill Brines

Journal of Food Protection ◽

10.4315/0362-028x-71.3.629 ◽

2008 ◽

Vol 71 (3) ◽

pp. 629-633 ◽

Cited By ~ 13

Author(s):

K. M. GAILUNAS ◽

K. E. MATAK ◽

R. R. BOYER ◽

C. Z. ALVARADO ◽

R. C. WILLIAMS ◽

...

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Lactic Acid Bacteria ◽

Thermal Processing ◽

Uv Light ◽

Light Exposure ◽

Meat Products ◽

Uv Treatment ◽

Bacterial Populations ◽

Log Reduction

Ready-to-eat meat products have been implicated in several foodborne listeriosis outbreaks. Microbial contamination of these products can occur after thermal processing when products are chilled in salt brines. The objective of this study was to evaluate UV radiation on the inactivation of Listeria monocytogenes and lactic acid bacteria in a model brine chiller system. Two concentrations of brine (7.9% [wt/wt] or 13.2% [wt/wt]) were inoculated with a ~6.0 log CFU/ml cocktail of L. monocytogenes or lactic acid bacteria and passed through a UV treatment system for 60 min. Three replications of each bacteria-and-brine combination were performed and resulted in at least a 4.5-log reduction in microbial numbers in all treated brines after exposure to UV light. Bacterial populations were significantly reduced after 5 min of exposure to UV light in the model brine chiller compared with the control, which received no UV light exposure (P < 0.05). The maximum rate of inactivation for both microorganisms in treated brines occurred between minutes 1 and 15 of UV exposure. Results indicate that in-line treatment of chill brines with UV light reduces the number of L. monocytogenes and lactic acid bacteria.

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

Journal of Food Protection ◽

10.4315/0362-028x-65.2.316 ◽

2002 ◽

Vol 65 (2) ◽

pp. 316-325 ◽

Cited By ~ 80

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.

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Effect of Age of Cook-in-Bag Delicatessen Meats Formulated with Lactate-Diacetate on the Behavior of Listeria monocytogenes Contamination Introduced When Opening the Packages during Storage

Journal of Food Protection ◽

10.4315/0362-028x.jfp-12-494 ◽

2013 ◽

Vol 76 (7) ◽

pp. 1274-1278 ◽

Cited By ~ 2

Author(s):

IFIGENIA GEORNARAS ◽

DARREN TOCZKO ◽

JOHN N. SOFOS

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Lactic Acid Bacteria ◽

Meat Products ◽

Potential Effect ◽

Meat Industry ◽

Storage Product ◽

Potassium Lactate ◽

Yeasts And Molds ◽

Effect Of Age

This study evaluated the potential effect of age of cook-in-bag ham and turkey breast delicatessen meats formulated with lactate-diacetate on survival and/or growth of Listeria monocytogenes introduced after opening of packages and slicing of product. Commercially prepared cured ham and turkey breast products formulated with potassium lactate and sodium diacetate were stored at 1.7°C unsliced, in their original cook-in-bags, and without postlethality exposure. On days 5, 90, 120, and 180 of storage, product slices (10.2 by 7.6 cm) were surface inoculated (1 to 2 log CFU/cm2) with a 10-strain mixture of L. monocytogenes, vacuum packaged (seven slices per bag), and stored at 4°C for up to 13 weeks. Inoculated levels of L. monocytogenes on both products were 1.4 to 1.5 log CFU/cm2. Irrespective of product age at slicing and inoculation, after 13 weeks of vacuum-packaged storage (4°C), pathogen counts on product slices were 1.5 to 2.3 (ham) and 2.3 to 2.5 (turkey) log CFU/cm2. Overall, the results of the study showed that the age of the cook-in-bag products prior to slicing and inoculation with the pathogen did not (P ≥ 0.05) affect the behavior of L. monocytogenes during vacuum-packaged storage (4°C, up to 13 weeks) of ham and turkey slices. Mean counts of lactic acid bacteria and yeasts and molds, when detected, did not exceed approximately 1 and 2 log CFU/cm2, respectively, among all stored samples. Findings of the study will be useful to the meat industry and risk assessors in their efforts to control L. monocytogenes in ready-to-eat meat products.

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Lactic acid bacteria isolated from traditional Italian dairy products: activity against Listeria monocytogenes and modelling of microbial competition in soft cheese

LWT ◽

10.1016/j.lwt.2020.110446 ◽

2021 ◽

Vol 137 ◽

pp. 110446

Author(s):

Felice Panebianco ◽

Filippo Giarratana ◽

Andrea Caridi ◽

Rossana Sidari ◽

Alessandra De Bruno ◽

...

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Lactic Acid Bacteria ◽

Dairy Products ◽

Microbial Competition ◽

Soft Cheese

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Behavior of Listeria monocytogenes and Other Microorganisms in Sliced Riojano Chorizo (Spanish Dry-Cured Sausage) during Storage under Modified Atmospheres

Microorganisms ◽

10.3390/microorganisms9071384 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1384

Author(s):

Elena Gonzalez-Fandos ◽

Maria Vazquez de Vazquez de Castro ◽

Alba Martinez-Laorden ◽

Iratxe Perez-Arnedo

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Lactic Acid Bacteria ◽

Potential Risk ◽

Meat Product ◽

Meat Products ◽

Modified Atmosphere ◽

Microbial Counts ◽

Modified Atmospheres ◽

Contamination Levels

Sliced ready-to-eat meat products packaged under modified atmospheres are often marketed since they cover consumer demands. The slicing process could be a potential risk for consumers since contamination with Listeria monocytogenes could occur during this stage. The current study evaluated the behavior of L. monocytogenes and other microorganisms in commercial sliced Riojano chorizo. This meat product was sliced and inoculated with L. monocytogenes (3.5 log CFU/g) before packaging under different atmospheres (air, vacuum, 100% N2, 20% CO2/80% N2 and 40% CO2/60% N2) and stored at 4 °C for up to 60 days. Samples were taken on days 0, 7, 21, 28 and 60 of storage. L. monocytogenes, mesophiles, Enterobacteriaceae, lactic acid bacteria, Micrococcaceae, molds and yeast counts were evaluated. Additionally, water activity, humidity and pH were determined. L. monocytogenes counts decreased in inoculated sliced chorizo during storage. Packaging conditions and day of storage influenced microbial counts. After 60 days, a significant reduction (p ≤ 0.05) in the initial Listeria contamination levels (3.5. log CFU/g) between 1.1 and 1.46 logarithmic units was achieved in the sausages packaged in modified atmosphere. The highest reductions were observed in slices packaged in 40% CO2/60% N2 after 60 days of storage at 4 °C.

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Pork meat products functional value and safety parameters improving by using lactic acid fermentation of savory plants

Journal of Food Science and Technology ◽

10.1007/s13197-015-1861-9 ◽

2015 ◽

Vol 52 (11) ◽

pp. 7143-7152 ◽

Cited By ~ 3

Author(s):

Elena Bartkiene ◽

Erika Mozuriene ◽

Grazina Juodeikiene ◽

Daiva Zadeike ◽

Audrius Maruska ◽

...

Keyword(s):

Lactic Acid ◽

Meat Products ◽

Lactic Acid Fermentation ◽

Pork Meat ◽

Acid Fermentation ◽

Functional Value ◽

Safety Parameters

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Efficacy of Cetylpyridinium Chloride against Listeria monocytogenes and Its Influence on Color and Texture of Cooked Roast Beef†

Journal of Food Protection ◽

10.4315/0362-028x-68.11.2349 ◽

2005 ◽

Vol 68 (11) ◽

pp. 2349-2355 ◽

Cited By ~ 10

Author(s):

M. SINGH ◽

H. THIPPAREDDI ◽

R. K. PHEBUS ◽

J. L. MARSDEN ◽

T. J. HERALD ◽

...

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Lactic Acid Bacteria ◽

Cetylpyridinium Chloride ◽

Meat Products ◽

Plate Count ◽

Bacterial Populations ◽

Plate Counts ◽

Roast Beef ◽

Aerobic Plate Count

Sliced (cut) and exterior (intact) surfaces of restructured cooked roast beef were inoculated with Listeria monocytogenes, treated with cetylpyridinium chloride (CPC; immersion in 500 ml of 1% solution for 1 min), individually vacuum packaged, and stored for 42 days at 0 or 4°C. Noninoculated samples were similarly treated, packaged, and stored to determine effects on quality (color and firmness) and on naturally occurring bacterial populations, including aerobic plate counts and lactic acid bacteria. Immediately after CPC treatment, regardless of inoculation level, L. monocytogenes populations were reduced (P = 0.05) by about 2 log CFU/cm2 on sliced surfaces and by about 4 log CFU/cm2 on exterior surfaces. Throughout 42 days of refrigerated storage (at both 0 and 4°C), L. monocytogenes populations on CPC-treated samples remained lower (P = 0.05) than those of nontreated samples for both surface types. After 42 days of storage at both 0 and 4°C, aerobic plate count and lactic acid bacteria populations of treated samples were 1 to 1.5 log CFU/cm2 lower (P = 0.05) than those of nontreated samples for both surface types. CPC treatment resulted in negligible effects (P > 0.05) on the color (L*, a*, and b* values) of exterior and sliced roast beef surfaces during storage. For both sliced and exterior surfaces, CPC-treated samples were generally less firm than nontreated samples. CPC treatment effectively reduced L. monocytogenes populations on roast beef surfaces and resulted in relatively minor impacts on color and texture attributes. CPC treatment, especially when applied to products prior to slicing, may serve as an effective antimicrobial intervention for ready-to-eat meat products.

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Effectiveness of Acidic Calcium Sulfate with Propionic and Lactic Acid and Lactates as Postprocessing Dipping Solutions To Control Listeria monocytogenes on Frankfurters with or without Potassium Lactate and Stored Vacuum Packaged at 4.5°C

Journal of Food Protection ◽

10.4315/0362-028x-67.5.915 ◽

2004 ◽

Vol 67 (5) ◽

pp. 915-921 ◽

Cited By ~ 36

Author(s):

MARYURI T. NUÑEZ de GONZALEZ ◽

JIMMY T. KEETON ◽

GARY R. ACUFF ◽

LARRY J. RINGER ◽

LISA M. LUCIA

Keyword(s):

Lactic Acid ◽

Listeria Monocytogenes ◽

Calcium Sulfate ◽

Limit Of Detection ◽

Meat Products ◽

Bactericidal Effect ◽

Antimicrobial Substances ◽

Potassium Lactate ◽

Residual Nitrite ◽

Plate Counts

The safety of ready-to-eat meat products such as frankfurters can be enhanced by treating with approved antimicrobial substances to control the growth of Listeria monocytogenes. We evaluated the effectiveness of acidic calcium sulfate with propionic and lactic acid, potassium lactate, or lactic acid postprocessing dipping solutions to control L. monocytogenes inoculated (ca. 108 CFU/ml) onto the surface of frankfurters with or without potassium lactate and stored in vacuum packages at 4.5° C for up to 12 weeks. Two frankfurter formulations were manufactured without (control) or with potassium lactate (KL, 3.3% of a 60% [wt/wt] commercially available syrup). After cooking, chilling, and peeling, each batch was divided into inoculated (four strains of L. monocytogenes mixture) and noninoculated groups. Each group was treated with four different dips: (i) control (saline solution), (ii) acidic calcium sulfate with propionic and lactic acid (ACS, 1:2 water), (iii) KL, or (iv) lactic acid (LA, 3.4% of a 88% [wt/wt] commercially available syrup) for 30 s. Noninoculated frankfurters were periodically analyzed for pH, water activity, residual nitrite, and aerobic plate counts (APCs), and L. monocytogenes counts (modified Oxford medium) were determined on inoculated samples. Surface APC counts remained at or near the lower limit of detection (<2 log CFU per frank) on franks with or without KL and treated with ACS or LA throughout 12 weeks at 4.5° C. L. monocytogenes counts remained at the minimum level of detection on all franks treated with the ACS dip, which indicated a residual bactericidal effect when L. monocytogenes populations were monitored over 12 weeks. L. monocytogenes numbers were also reduced, but not to the same degree in franks made without or with KL and treated with LA. These results revealed the effectiveness of ACS (bactericidal effect) or LA (bacteriostatic effect) as postprocessing dipping solutions to inhibit or control the growth of L. monocytogenes on vacuum-packaged frankfurters stored at 4.5° C for up to 12 weeks.

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