From beans to chicken, a lot of leftover food always finds its way either into people’s stomachs the next day or the dustbin. But how should one treat surplus food if they have plans of consuming it?

Dr Olivier Manzi Umulisa, a specialist in infectious diseases at University Teaching Hospital (CHUK), says provided food is kept well without favourable conditions to allow microbial growth, it is as safe as a fresh meal.

Manzi warns though that the biggest and likely problem is bacteria which thrive in poorly kept food materials and efforts should be made to ensure safe storage.

Recommended temperatures

"All sorts of food should be kept below or above the danger zone which is usually between 40° and 140° F (4° and 60° C),” Manzi explains. "Even with the commonest methods of food preservation and preparation such as freezing or heat treatments, safety is either below or above this temperature.”

According to the expert, below the danger zone microorganisms are inactivated yet above this temperature, bacteria cells are denatured.

Then why not keep the broken fries and vegetable from the previous meal at chilled temperatures than just trashing everything in the garbage cans.

CHUK nutritionist Joseph Uwiragiye advises that food should rather be kept cold or hot but not warm because keeping food dishes warm only provides suitable conditions for bacterial growth.

"For that reason, when certain foods that are heat sensitive are kept warm such as milk, they are likely to get spoilt in a short period of time meaning storing them at warm temperatures only worsens their palatability,” Uwiragiye explains.

Other health experts also caution people on the practice of cooking food once and picking bits thereafter for several days or the entire week. They risk consuming food with poisonous microorganisms.

Consuming contaminated fruit juices

The international journal of food microbiology throws more weight behind the dangers of keeping fruit juices at non recommended temperatures.

According to the journal, this juice is spoilt primarily due to proliferation of acid tolerant and osmophilic microflora (salt loving microorganisms).

It also goes ahead to suggest that there exists a possible risk of food borne microbial infections associated with the consumption of fruit juices that would most likely be prevented if fruit juices are preserved or stored by various techniques.

Among the methods suggested is thermal pasteurization similar to that used commercially by fruit juice industries for the preservation, but warns it may result in losses of essential nutrients and changes in physicochemical and organoleptic properties.

Dumping food is not good

However Audrey Mutabazi, a food consultant, also expresses concern over food wastage but suggests that people should adapt to better methods of food preservation provided they consume the food at a later stage.

"It is possible to make good use of every single food material that could otherwise end up piled as rubbish after spending good sums of money on it,” Mutabazi mentions.

Mutabazi’s concern is that each time food is thrown, it is because of poor preparation, preservation and utilization yet also if consumed when bad, then food poisoning is a likely scenario.

Studies by the Food and Agriculture Organization in Sub-Saharan Africa also indicate that each person in Sub-Saharan Africa loses 6 to 11kgs of food per year which would otherwise be avoided if left over foods are utilized.

Minced meat

Mutabazi therefore advises that when it comes to meaty products particularly minced meat should preferably be used immediately because of an increased surface area for microbial proliferation.

"The fact that it is chopped in tiny pieces means bacteria can easily thrive there.  However, previously frozen food chunks should not be kept at room temperature after thawing,” Mutabazi advises.