Heat treated food rapid chilling

Dear all, good day,

Could anyone explain me why do we need to rapidly chill heat treated food?

As far as I've understood, food heating results in oxygen reduction and slow chilling allow mesophilic anaerobes to proliferate (there is medium temperature and lack of oxygen).

Still I do not understand why high temperature actually results in oxygen depletion? What processes are carried out at that time? And is there any problem for oxygen to penetrate food after chilling start?

Dear all, good day,

Could anyone explain me why do we need to rapidly chill heat treated food?

Hi Constantine,

:welcome:

The main reason is that some foods may contain spores that survive the heat treatment and are then able to grow if the food is not kept hot (>63°C) or cooled quickly to refrigeration temperatures. One example is Bacillus cereus.

Regards,

Tony

Hi Tony!

Thanks a lot! It's clear for me now :smile:

Hi Tony!

Thanks a lot! It's clear for me now :smile:

No problem Constantine, feel free to post any questions you may have on the forums, I'm sure you will find that our members are more than willing to help.

Regards,

Tony

Dear all, good day,

Could anyone explain me why do we need to rapidly chill heat treated food?

As far as I've understood, food heating results in oxygen reduction and slow chilling allow mesophilic anaerobes to proliferate (there is medium temperature and lack of oxygen).

Still I do not understand why high temperature actually results in oxygen depletion? What processes are carried out at that time? And is there any problem for oxygen to penetrate food after chilling start?

I'm not sure the constitution of your product (proteins, starch, veg, etc.) but the fact remains that blast chilling (or other rapid chilling procedures) creates a much better quality product as well. The moisture loss in cooking cooling is a result of the damage that takes place in cell structure. This happens in freezers at home when product isn't sealed properly. Sous vide is a process rapidly gaining notoriety for not only food safety, but quality as well. It brings in another realm of food safety considerations to make, but what doesn't? Might be worth a look for you.

In short, rapid chilling is the only way, unless you don't have the means and can take this into consideration in your product formulation.

Ekivlen, to be clear, I was reading Prescott's Principles of microbiology and there was an explanation of Clostridium perfringens food-borne intoxication: if meat products are heated, this results in oxygen depletion, then if this products are cooled slowly, microorganism proliferation can occur. Also I remember, that milk factories prefer to cool pasteurized milk as rapidly as possible. I was wondering why we actually need this quick cooling, so my interest is in food safety, but thanks for additional information about quality improvement :smile:

Actually I'm going to deal with crackers and potato chips production, so my products are mainly composed of carbohydrates.

Tony, I am still a little puzzled by the phrase 'oxygen depletion'. C. perfringens is a strict anaerobe and can sporulate. So do I understand correctly the whole mechanism?:

1) we heat meat, C. perfringens sporulate, meat oxygen is reducing (but why do we loose O₂ in the product?);

2) if we cool slowly, spores become bacteria and they contaminate the meat (and this is possible due to moderate temperature and oxygen absence).

Thanks! :smile: