522 ◾ Fundamental Food Microbiology
destroy bacterial spores. Many types of food are currently being studied for pressure pasteurization,
and a few are now commercially produced. A brief list of these is included in Table 40.2.
Some of the results from studies with processed meat products or alfalfa seeds are presented
here. 28,29 In each of these studies, a five-strain mixture of pressure-resistant Lis. monocytogenes,
Salmonella serovars, and Esc. coli O157:H7 was inoculated either at a high (~10 7 /g) or a low (~10 3 /g)
level to frankfurters in packages, some of which were then inoculated with a mixture of two
bacteriocins, pediocin and nisin. The bags were then pressurized at 345 MPa for five minutes at
50°C (122°F). Packages with high-level inoculation were enumerated for the survivors immediately after pressurization. Packages with low-level inoculation were stored at 4°C, and at selected
intervals, multiple packages were tested for the survivors both by enumeration and by isolation
table 40.1 Some Potential Applications of High Hydrostatic Pressure in Food
1. Antimicrobial Applications
• To destroy microbial cells at lower pressure range
• To destroy bacterial spores at higher pressure range
• To germinate bacterial spores at lower pressure range
• To prevent microbial growth in unfrozen food
2. Novel Product Development
• To produce fruit and vegetable products with natural taste
• To improve color of fruit products and egg yolks
• To facilitate gelation of proteins without heat
3. Improved Food Processing
• To tenderize meat
• To enhance cheese ripening
• To open valves of shellfish
• To inactivate undesirable food enzymes
• To thaw frozen food rapidly
• To store food unfrozen at –20°C
• To inactivate allergens and toxins
table 40.2 Current Status of Food Product Development
• Fruit products: juices, jellies, jams, cut fruits, fruit yogurt
• Vegetable products: avocado dip, salsa
• Meat products: roast beef, salami, sausage, frankfurters, foie gras
• Seafood products: smoked salmon cream, oysters, surimi
• Miscellaneous: Spanish rice, spaghetti, rice wine
destroy bacterial spores. Many types of food are currently being studied for pressure pasteurization,
and a few are now commercially produced. A brief list of these is included in Table 40.2.
Some of the results from studies with processed meat products or alfalfa seeds are presented
here. 28,29 In each of these studies, a five-strain mixture of pressure-resistant Lis. monocytogenes,
Salmonella serovars, and Esc. coli O157:H7 was inoculated either at a high (~10 7 /g) or a low (~10 3 /g)
level to frankfurters in packages, some of which were then inoculated with a mixture of two
bacteriocins, pediocin and nisin. The bags were then pressurized at 345 MPa for five minutes at
50°C (122°F). Packages with high-level inoculation were enumerated for the survivors immediately after pressurization. Packages with low-level inoculation were stored at 4°C, and at selected
intervals, multiple packages were tested for the survivors both by enumeration and by isolation
table 40.1 Some Potential Applications of High Hydrostatic Pressure in Food
1. Antimicrobial Applications
• To destroy microbial cells at lower pressure range
• To destroy bacterial spores at higher pressure range
• To germinate bacterial spores at lower pressure range
• To prevent microbial growth in unfrozen food
2. Novel Product Development
• To produce fruit and vegetable products with natural taste
• To improve color of fruit products and egg yolks
• To facilitate gelation of proteins without heat
3. Improved Food Processing
• To tenderize meat
• To enhance cheese ripening
• To open valves of shellfish
• To inactivate undesirable food enzymes
• To thaw frozen food rapidly
• To store food unfrozen at –20°C
• To inactivate allergens and toxins
table 40.2 Current Status of Food Product Development
• Fruit products: juices, jellies, jams, cut fruits, fruit yogurt
• Vegetable products: avocado dip, salsa
• Meat products: roast beef, salami, sausage, frankfurters, foie gras
• Seafood products: smoked salmon cream, oysters, surimi
• Miscellaneous: Spanish rice, spaghetti, rice wine