Question

You have decided to try your hand at canning some of your homegrown green beans from the garden. You rinse the beans, add water, and put them into Mason jars. You are in a hurry, so you decide to shorten the boiling time to 5 minutes to speed the process up. The jars seal properly, as you can tell from the vacuum created by the lids. You store the jars on your kitchen shelf for 3 months. Are the beans safe to eat now? Why or why not? What type of microbe might be present, and why? If you were making canned pickles, would the above problem be likely to occur? Explain why or why not.

Answer 1

Canning is a food preservation method that employs the process of heating and sealing the food in containers for the purpose of storage.

The main objective of heat application is to destroy pathogenic and spoilage microorganisms, and at the same time, the hermetic container prevents contamination by new microorganisms.

An optimal thermal process will destroy pathogenic bacteria, kill or control spoilage organisms present, and have minimal impact on the nutritional and physical qualities of the food.

If we shorten the temperature some organisms may able to survive and cause spoilage on the further process.

Since beans is a low-acid food (pH 4.5–7) that will provide a favorable environment for microorganisms and must be canned at higher temperatures.

If there is no oxygen in the container, aerobic microorganisms cannot grow but anaerobic microbes that survive the heating process can grow in this environment.

The presence of heat-resistant microorganism, specifically the spores of Clostridium botulinum, which can produce a deadly toxin if they sprout and grow under the anaerobic conditions of a canned food.

Clostridium botulinum spores are resistant reproductive bodies are present in the soil and can contaminant fruits and vegetables.

Botulism is a paralytic illness caused by ingestion of the toxin produced by Clostridium botulinum.Death results from muscle paralysis and respiratory failure.

☆ Spores of botulinum will not germinate and organism cannot survive under acidic conditions.

Pickled beans are covered in an acidified brine, the process creates a high enough acidity to prevent the risk of botulism.

So picklng make it safe from botulinum.

But shortened temperature causes the survival of some mesophilic bacteria and lactic acid bacteria.

Mesophilic can grow at moderate temperature and lactic acide bacteria are acide tolerant.

Under anearobic condition these organisms are also unable to survive.But the traces of oxygen can spoil the item.