Thermal Food Processing

80 Thermal Food Processing: New Technologies and Quality Issues
TABLE 3.3
Lethality Values (F o) for Commercial Sterilization
of Selected Canned Food Products
Product Can sizes F o (min)
Asparagus 2
Green beans, brine packed No. 2 3.5
No. 10 3.5
Chicken, boned All 6–8
Corn, whole kernel, brine packed All 9
No. 10 15
Cream-style corn No. 2 5–6
No. 10 2.3
Dog food No. 2 12
No. 10 6
Mackerel in brine 301 × 411 2.9–3.6
Meat loaf No. 2 6
Peas, brine packed No. 2 7
No. 10 11
Sausage, Vienna, in brine Various 5
Chili con carne Various 6
Source: Lopez, A.A., Complete Course in Canning, Book 1, Basic
Information on Canning, 11th ed., The Canning Trade, Baltimore,
1987. Courtesy of American Can Company, Inc.
Where thermophilic spoilage is a problem, more severe processes may be
necessary because of the high heat resistance of thermophilic spores. Fortunately,
most thermophiles do not grow readily at room temperature and require incubation
at unusually high storage temperatures (45 to 55°C) to cause food spoilage.
Generally, foods with no more than 1% spoilage (spoilage probability of 10 –2 )
upon incubation after processing will meet the accepted 10 –5 spoilage probability
in normal commerce. Therefore, when thermophilic spoilage is a concern, the
target value for the final number of survivors is usually taken as 10 –2 , and the
initial spore load needs to be determined through microbiological analysis since
contamination from these organisms varies greatly. For a situation with an initial
thermophilic spore load of 100 spores per can, and an average D 121 value of 4.00,
the process lethality required would be
F = 400 . (log100−log 001 . )
= 4004 . ( )
= 16
The procedural steps above are only preliminary guidelines for average conditions,
and often need to be adjusted up or down in view of the types of contaminating