Manufacturing experiments without the use of preservatives 15
Outline of experiments 15
Discussion of results 17
Spoilage of ketchup after opening 17
Spoilage of unopened ketchup 20
Spoilage of market brands 20
Sterility of ketchup 21
Experiments with preservatives 22
Sodium benzoate 22
Salt 23
Sugar 23
Spices 24
Water infusions 24
Acetic acid extracts 25
Oil extracts 25
Vinegar and acetic acid 26
Oil 27
Study of Penicillium in ketchup 28
Development 29
Reproduction 29
Growth in ketchup 30
Temperature tests 31