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High-pressure processing of Turkish white cheese for microbial inactivation
G Akdemir Evrendilek1, N Koca, J W Harper
1Department of Food Engineering, Faculty of Agriculture, Mustafa Kemal University, 31034 Alahan, Hatay, Turkey. gevrendilek@yahoo.com
Journal of Food Protection
|February 2, 2008
Summary
High-pressure processing (HPP) effectively reduces microbial load in Turkish white cheese. This method significantly decreases Listeria monocytogenes and other bacteria, with greater reductions at higher pressures.
Area of Science:
- Food Science
- Microbiology
- Food Processing Technology
Background:
- Turkish white cheese is susceptible to microbial contamination, impacting shelf-life and safety.
- Controlling pathogens like Listeria monocytogenes is crucial for food safety in dairy products.
Purpose of the Study:
- To investigate the efficacy of high-pressure processing (HPP) in reducing microbial populations in Turkish white cheese.
- To evaluate the impact of HPP on Listeria monocytogenes and other indicator microorganisms in cheese made from raw and pasteurized milk.
Main Methods:
- Turkish white cheese samples (raw and pasteurized milk) were inoculated with Listeria monocytogenes.
- Samples were subjected to high-pressure processing (HPP) at pressures ranging from 50 to 600 MPa for 5 and 10 minutes at 25°C.
- Microbial counts (L. monocytogenes, total aerobic mesophilic bacteria, Enterobacteriaceae, molds, yeasts, Lactococcus spp., Lactobacillus spp.), pH, and water activity were analyzed.
Main Results:
- HPP significantly reduced L. monocytogenes, total aerobic mesophilic bacteria, Lactococcus spp., and Lactobacillus spp. in both raw and pasteurized milk cheeses.
- Reductions in total molds, yeasts, and Enterobacteriaceae were observed in raw milk cheese, increasing with pressure.
- Maximum L. monocytogenes reduction (approx. 4.9 log CFU/g) was achieved at 600 MPa. Pasteurization eliminated molds, yeasts, and Enterobacteriaceae prior to HPP.
- No significant differences in microbial inactivation were found between raw and pasteurized milk cheeses or between 5- and 10-minute treatment times.
- HPP did not significantly alter the pH or water activity of the cheese samples.
Conclusions:
- High-pressure processing (HPP) is an effective technology for reducing the microbial load in Turkish white cheese.
- HPP offers a promising non-thermal processing method for enhancing the microbiological safety and potentially extending the shelf-life of Turkish white cheese.
- The study demonstrates the potential of HPP as a viable alternative to traditional pasteurization for certain microbial targets in cheese production.
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