preserves & food safety

With the wonderful modern conveniences of refrigerators and freezers, the art of preserving is no longer an essential kitchen skill. But that doesn’t mean preserving is a waste of time. Far from it.

what causes food to spoil?

There are 2 major causes of food spoilage
1. Micro organisms – bacteria, yeast, moulds & fungi
Microbes are the biggest concern from a food safety perspective because they can make us ill and some can also kill us. Heat is one of the most common methods of killing microbes. High sugar environments (or low moisture) such as in jams or the pear ‘cheese’ also prevent microbes from growing.

High acid (low pH), as in pickles, is another way to control microbes.

If you’re interested in this, make sure you read a quick word about botulism.

2. Oxygen
Oxidation is the technical term for the browning that happens when you leave the cut surface of an apple exposed to the air. It’s more of a loss of quality problem, rather than a safety issue.

The enzymes or chemicals which promote browning are slowed down by acid and destroyed by heat. Providing a barrier to the oxygen by sealing in a jar or covering with water also helps.

4 ‘rules’ of food safety

1. be as clean as possible
The first line of defense is to keep your hands, equipment and kitchen surfaces free from potential sources of bacteria, yeasts & fungi.

2. avoid cross contamination
This is super critical for meats and fish but also essential in preserving. Make sure your preserved or cooked food NEVER touches the same surface as your raw food without cleaning or sterilising in between.

3. keep things hot or keep them chillied
Most microbes like a nice warm environment to thrive. Best to keep your food out of the ‘danger zone’ by keeping it either above 60C (140F) or in the fridge (below 4C / 39F).

4. if in doubt, chuck it out
If you suspect a food is ‘off’ it’s not worth the risk to you and your family to eat it anyway. Signs of spoilage include mould growth, the presence of gas, bulging containers and off odours.

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