Comparative study on the acceptability and consumer appeal of commercial products and research-optimised low-salt frankfurters and cooked ham manufactured using high-pressure processing and organic acids

Formulations with lactate as an antimicrobial and high-pressure processing (HPP) as a lethal treatment are combined strategies used to control L. monocytogenes in cooked meat products. Previous studies have shown that when HPP is applied in products with lactate, the inactivation of L. monocytogenes is lower than that without lactate. The purpose of the present work was to identify the molecular mechanisms underlying the piezo-protection effect of lactate. Two L. monocytogenes strains (CTC1034 and EGDe) were independently inoculated in a cooked ham model medium without and with 2.8% potassium lactate. Samples were pressurized at 400 MPa for 10 min at 10 °C. Samples were subjected to RNA extraction, and a shotgun transcriptome sequencing was performed. The short exposure of L. monocytogenes cells to lactate through its inoculation in a cooked ham model with lactate 1h before HPP promoted a shift in the pathogen’s central metabolism, favoring the metabolism of propanediol and ethanolamine together with the synthesis of the B12 cofactor. Moreover, the results suggest an activated methyl cycle that would promote modifications in membrane properties resulting in an enhanced resistance of the pathogen to HPP. This study provides insights on the mechanisms developed by L. monocytogenes in response to lactate and/or HPP and sheds light on the understanding of the piezo-protective effect of lactate.

Download Full-text

Effect of high-pressure processing and natural antimicrobials on the shelf-life of cooked ham

Czech Journal of Food Sciences ◽

10.17221/204/2018-cjfs ◽

2019 ◽

Vol 37 (No. 1) ◽

pp. 57-61

Author(s):

Markéta Adamcová ◽

Vincent van Andel ◽

Jan Strohalm ◽

Milan Houška ◽

Rudolf Ševčík

Keyword(s):

High Pressure ◽

Shelf Life ◽

Storage Period ◽

High Pressure Processing ◽

Processing Plant ◽

Microbial Count ◽

Natural Antimicrobials ◽

Natural Sources ◽

Cooked Ham ◽

Potassium Lactate

The need to reduce the content of questionable health preservatives leads to the search for new methods to extend the shelf-life of meat products. The spectrum of possible approaches includes physical methods and the use of additives from natural sources. In this study, we examined the influence of the combination of high-pressure processing (HPP) and the addition of natural antimicrobials on the shelf-life of cooked ham. The samples of cooked ham were produced in a professional meat processing plant. One half of the samples were produced according to a traditional recipe, and the other was enriched with potassium lactate in the form of a commercial product PURASAL<sup>®</sup> Hirer P Plus. This product is produced via sugar fermentation and contains high levels of potassium lactate, a compound with high antimicrobial activity. Cooked hams were inoculated by bacteria Serratia liquefaction, vacuum packaged and treated by HPP. Packaged ham samples were stored at 3°C for 40 days and the total microbial count was examined during this storage period in defined intervals. The combination of HPP and potassium lactate from natural sources significantly reduced the total microbial counts in cooked hams and, thus, could be a suitable solution for the meat industry.

Download Full-text

Inhibition of Listeria monocytogenes in Cooked Ham through Active Packaging with Natural Antimicrobials and High-Pressure Processing

Journal of Food Protection ◽

10.4315/0362-028x-70.11.2498 ◽

2007 ◽

Vol 70 (11) ◽

pp. 2498-2502 ◽

Cited By ~ 42

Author(s):

ANNA JOFRÉ ◽

MARGARITA GARRIGA ◽

TERESA AYMERICH

Keyword(s):

High Pressure ◽

Listeria Monocytogenes ◽

Active Packaging ◽

High Pressure Processing ◽

The Other ◽

Lag Phase ◽

Natural Antimicrobials ◽

Cooked Ham ◽

Potassium Lactate

Enterocins A and B and sakacin K at 200 and 2,000 activity units (AU)/cm2, nisin at 200 AU/cm2, 1.8% potassium lactate, and a combination of 200 AU/cm2 of nisin and 1.8% lactate were incorporated into interleavers, and their effectiveness against Listeria monocytogenes spiked in sliced, cooked ham was evaluated. Antimicrobial-packaged cooked ham was then subjected to high-pressure processing (HPP) at 400 MPa. In nonpressurized samples, nisin plus lactate–containing interleavers were the most effective, inhibiting L. monocytogenes growth for 30 days at 6°C, with counts that were 1.9 log CFU/g lower than in the control after 3 months. In the other antimicrobial-containing interleavers, L. monocytogenes did not exhibit a lag phase and progressively grew to levels of about 8 log CFU/g. HPP of actively packaged ham slices reduced Listeria populations about 4 log CFU/g in all batches containing bacteriocins (i.e., nisin, sakacin, and enterocins). At the end of storage, L. monocytogenes levels in the bacteriocin-containing batches were the lowest, with counts below 1.51 log CFU/g. In contrast, HPP moderately reduced L. monocytogenes counts in the control and lactate batches, with populations gradually increasing to about 6.5 log CFU/g at the end of storage.

Download Full-text