Microbiological Changes in Pressurized, Prepackaged Sliced Cooked Ham

1999 ◽  
Vol 62 (12) ◽  
pp. 1411-1415 ◽  
Author(s):  
M. E. LÓPEZ-CABALLERO ◽  
J. CARBALLO ◽  
F. JIMÉNEZ-COLMENERO

This was a study of the influence of high-pressure conditions (200 and 400 MPa, 5 and 20 min, 7°C) on microbiological quality and water-binding properties of vacuum-prepackaged sliced cooked ham and how this affects microbiological changes during chilled storage (2°C). Pressurization caused a degree of microbiological inactivation, which increased with pressure level and processing time. Pressurization at 400 MPa significantly reduced the total viable count and lactic acid bacteria to the extent that after 20 min no Enterobacteriaceae, Baird Parker flora, or Brochothrix thermosphacta were detected throughout any of the chilled storage periods studied. In general, gram-positive flora was more resistant to pressure than gram-negative flora. The fact that high pressure (400 MPa) causes considerable inactivation of microorganisms could be used to prolong the shelf life of vacuum-prepackaged sliced cooked ham.

2000 ◽  
Vol 63 (2) ◽  
pp. 196-201 ◽  
Author(s):  
M. E. LÓPEZ-CABALLERO ◽  
M. PÉREZ-MATEOS ◽  
P. MONTERO ◽  
A. J. BORDERÍAS

The purpose of this study was to analyze the effect of 10-min continuous pressure and pulsed pressure in two 5-min steps (400 MPa at 7°C) on the microbial flora, total volatile bases, pH, and texture of purified and unpurified oysters. High-pressure treatment reduced the number of all the target microorganisms (total viable count, H2S-producing microorganisms, lactic acid bacteria, Brochothrix thermosphacta, and coliforms), in some cases by around 5-log units. The difference between the counts in the control and the pressurized oysters remained stable throughout 41 days of storage at 2°C. No Salmonella spp. were detected in either the control batch or the pressurized batches during this storage period. Deterioration of the oyster was accompanied by increased total volatile bases, mainly in the nonpressurized samples. The pH was practically constant in the pressurized oysters and fell slightly in unpressurized samples. As for mechanical properties, shear strength values were higher in pressurized than in unpressurized oysters. Step-pulse pressurizing (400 MPa at 7°C in two 5-min pulses) produced no apparent advantages over continuous pressurizing based on any of the indices used.


Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 17
Author(s):  
Malco C. Cruz-Romero ◽  
Claire C. O’Flynn ◽  
Declan Troy ◽  
Anne M. Mullen ◽  
Joe P. Kerry

The objective of this study was to investigate the use of potassium chloride (KCl) and tapioca starch (TS) to reduce salt levels below 1.5% in sausages manufactured using previously high pressure (HP) processed pork (150 MPa). A 3 × 2 × 1 factorial design was used to formulate breakfast sausages with three salt levels (0.5%, 1.0%, and 1.5%), two ingredient levels (no added ingredient or added as a combination of KCl\TS), and one pressure level (150 MPa). Partial replacement of NaCl with KCl and addition of TS had beneficial effects on the water binding abilities of sausage batters by decreasing (p < 0.05) total expressible fluid (%) and increasing water holding capacity (%). Overall, results indicated that the use of KCl\TS imparted some beneficial effects to salt-reduced low fat breakfast sausages and has the potential to reduce salt levels in the breakfast sausages to 1.0% while still maintaining the organoleptic and functional properties traditionally associated with these meat products.


Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 677
Author(s):  
Cristina Serra-Castelló ◽  
Ilario Ferrocino ◽  
Anna Jofré ◽  
Luca Cocolin ◽  
Sara Bover-Cid ◽  
...  

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.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Dianbin Su ◽  
Xin-Di Zhu ◽  
Yong Wang ◽  
Dong Li ◽  
Li-Jun Wang

Abstract Citrus fiber dispersion with different concentrations (5–25 g/kg) was treated by high-pressure homogenization (90 and 160 MPa) for two cycles. The particle size distribution, hydration properties of powders, morphology and rheological measurements were carried out to study the microstructure and rheological properties changes by high-pressure homogenization (HPH). In conclusion, the HPH can reduce the particle size of fiber, improve the water holding capacity and water binding capacity. Furthermore, fiber shape can be modified from globular cluster to flake-like slices, and tiny pores can be formed on the surface of citrus fiber. The apparent viscosity, storage modulus and loss modulus were increased by HPH whereas the activation energy was reduced. The Hershcel–Bulkley model, Carreau model and Power Law mode were selected to evaluate the rheological properties.


2012 ◽  
Vol 27 (2) ◽  
pp. 494-502 ◽  
Author(s):  
Ulrike Einhorn-Stoll ◽  
Hyoe Hatakeyama ◽  
Tatsuko Hatakeyama

2012 ◽  
Vol 75 (3) ◽  
pp. 497-503 ◽  
Author(s):  
YANG LIU ◽  
MIRKO BETTI ◽  
MICHAEL G. GÄNZLE

This study evaluated the high pressure inactivation of Campylobacter jejuni, Escherichia coli, and poultry meat spoilage organisms. All treatments were performed in aseptically prepared minced poultry meat. Treatment of 19 strains of C. jejuni at 300 MPa and 30°C revealed a large variation of pressure resistance. The recovery of pressure-induced sublethally injured C. jejuni depended on the availability of iron. The addition of iron content to enumeration media was required for resuscitation of sublethally injured cells. Survival of C. jejuni during storage of refrigerated poultry meat was analyzed in fresh and pressure-treated poultry meat, and in the presence or absence of spoilage microbiota. The presence of spoilage microbiota did not significantly influence the survival of C. jejuni. Pressure treatment at 400 MPa and 40°C reduced cell counts of Brochothrix thermosphacta, Carnobacterium divergens, C. jejuni, and Pseudomonas fluorescens to levels below the detection limit. Cell counts of E. coli AW1.7, however, were reduced by only 3.5 log (CFU/g) and remained stable during subsequent refrigerated storage. The resistance to treatment at 600 MPa and 40°Cof E. coli AW1.7 was compared with Salmonella enterica, Shiga toxin–producing E. coli and nonpathogenic E. coli strains, and Staphylococcus spp. Cell counts of all organisms except E. coli AW 1.7 were reduced by more than 6 log CFU/g. Cell counts of E. coli AW1.7 were reduced by 4.5 log CFU/g only. Moreover, the ability of E. coli AW1.7 to resist pressure was comparable to the pressure-resistant mutant E. coli LMM1030. Our results indicate that preservation of fresh meat requires a combination of high pressure with high temperature (40 to 60°C) or other antimicrobial hurdles.


Sign in / Sign up

Export Citation Format

Share Document