Vegetables belonging to the low acid group (pH above 4.5) in which heat resistant bacteria are found. Inadequate heat processing permits the survival of Clostridium botulinum, the organism responsible for botulism type of food intoxication. It is advised that home-scale canning of vegetables and other low and medium acid foods be avoided. Canning of these products should only be done under the strict supervision of Food Technologists.
Instruments/Chemicals
- Rotary Washer
- Steel Kettle
- Shredder
- Salt
- Glass Jar
- Exhaust Box
- Retort
Procedure
- Select only freshly picked, tender spinach.
- Wash the spinach in running water or in a rotary washer to remove all dirt and other contaminants.
- Trim brown leaves, decayed spots and cut tough stems and midribs.
- Blanch in steam or boiling water for 2 to 5 min.
- Cool by water spray. Turn the spinach over to cool rapidly.
- Shred the spinach using a shredder.
- Weigh 6 g salt into No. 2 can or glass jar.
- Pack into No. 2 can – net weight to be 350 g.
- Fill with hot water to 1/4″ head space.
- Exhaust to can centre temperature of 78 °C and seal.
- Process cans (size 2) and glass jars for 45 and 50 minutes, respectively at 121 °C (15 lb. pressure per square inch) or 70 and 90 minutes at 115 °C (10, lb. pressure per square inch).
- Cool immediately to 43 °C and store in a cool dry place.
