High-pressure and thermal-assisted pasteurization of habituated, wild-type, and pressure-stressed Listeria monocytogenes, Listeria innocua, and Staphylococcus aureus

LWT ◽  
2021 ◽  
Vol 137 ◽  
pp. 110445
Author(s):  
Md Niamul Kabir ◽  
Sadiye Aras ◽  
Jyothi George ◽  
Sabrina Wadood ◽  
Shahid Chowdhury ◽  
...  
2008 ◽  
Vol 71 (10) ◽  
pp. 2110-2114 ◽  
Author(s):  
P. ELIZAQUÍVEL ◽  
R. AZNAR

Four commercial DNA extraction methods, PrepMan Ultra (Applied Biosystems), InstaGene Matrix (BioRad), DNeasy Tissue kit (Qiagen), and UltraClean (MoBio), were tested for PCR detection of Listeria monocytogenes, Escherichia coli O157: H7, Salmonella, and Staphylococcus aureus in fresh, minimally processed vegetables. For comparative purposes, sensitivity assays with specific PCRs were carried out after DNA extraction with the four methods in green pepper, broccoli, and onion artificially inoculated with the four pathogens separately. As confirmed by statistical analysis, the DNeasy Tissue kit rendered the highest sensitivity values in the three matrices assayed for Salmonella, L. monocytogenes, and E. coli O157:H7 and in onion for S. aureus. Despite being the most expensive of the methods compared, the DNeasy Tissue Kit can be successfully applied for any of the four most commonly studied pathogens, thus saving time and overall reducing the cost of the analysis.


1996 ◽  
Vol 59 (8) ◽  
pp. 813-818 ◽  
Author(s):  
RONALD A. HEDDLESON ◽  
STEPHANIE DOORES ◽  
RAMASWAMY C. ANANTHESWARAN ◽  
GERALD D. KUHN

The chemical composition of five foods (UHT milk, beef broth, pudding, cream sauce, and liquid whole egg) was examined to determine factors important in achieving uniform temperatures within foods heated in a 700 W microwave oven. Proximate analyses were performed on all food systems to relate their chemical composition to temperatures and to destruction of microwave-heated Salmonella species, Listeria monocytogenes Scott A and V7 and Staphylococcus aureus ATCC 25923. Microwave heating times were chosen such that the final mixed mean temperature achieved by systems was 60°C for Salmonella spp. and L. monocytogenes, and 65°C for S. aureus. The amount of destruction of Salmonella spp. varied from 3.17 log CFU/ml in UHT milk to 0.44 log CFU/ml in beef broth. L. monocytogenes strains incurred the greatest amount of destruction in pudding (2.39 log CFU/g), while the least amount of destruction was observed in cream sauce (1.63 log CFU/ml). There were no significant differences in the amount of destruction of S. aureus heated in the five foods. The pH and aw of these foods did not affect survival of thermally stressed Salmonella, L. monocytogenes, or S. aureus cells. Of the food components examined, sodium content was the primary influence on the uniformity of temperatures achieved within foods, and, in turn, on the survival of bacteria.


2008 ◽  
Vol 71 (2) ◽  
pp. 325-332 ◽  
Author(s):  
YONG-SUK KIM ◽  
ZIAN-BIN ZHENG ◽  
DONG-HWA SHIN

Kimchi is a unique Korean traditional vegetable product that is fermented by lactic acid bacteria (LAB) and is mainly consumed as a side dish with boiled rice. Its main ingredients are brined Chinese cabbage, red pepper powder, and fermented fish sauce, and these are combined with many spices such as garlic, green onion, ginger, and some seaweed. The relationship between the concentration of LAB or the pH and the growth of three gram-positive foodborne pathogens (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) was evaluated. Heat treatment (HT; 85°C for 15 min) or neutralization treatment (NT; pH 7.0) was conducted on day 0 (0-D group) and day 3 (3-D group) of incubation. The pH in the control group and the NT group dropped sharply to 4.12 to 4.30 after 2 days of incubation and slightly decreased thereafter, whereas the pH in the control group and HT group stayed at 7.0 during incubation. LAB were not detected in the HT kimchi during incubation. B. cereus in the NT-0-D, NT-3-D, and HT-3-D groups was reduced by 1.5 to 3.1 log CFU/ml but increased slightly in the HT-0-D group. L. monocytogenes in HT-3-D and NT-3-D groups disappeared after 5 days of incubation, and S. aureus in the NT-0-D group disappeared after 4 days. These findings indicate that growth of all the foodborne pathogens was inhibited by NT-0-D, HT-3-D, and NT-3-D, but B. cereus was not inhibited by HT-0-D. Thus, growth of LAB in kimchi is an important factor in the control of foodborne pathogens.


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