Food Science 2 (Heat Processing)

Pasterurization (name two objectives as well)

Still affects color flavor texture Objectives are Destory pathogenic microorganismms of food and public health significant ( what makes people sick) 2) extend products shelf life from a microbial and enzymatic point of view (kill spoilage organisms) Have to be refrigerated (1-2) weeks of shelf life, and contain many live organisms Some pasteurized foods: eggs, juices, wine, milk, beer, meat Steaming of ovsters in shelf

D Value

minutes required at a specific temperatures temperature needed to destroy 90% of the microorganisms in a specific product

Modern Retort

steel cans placed under pressure with fluctuating temperatures to counterbalance the pressure in the can

Does heating or cooking provide a sterile product?

No

First Patent Can Opener

(during civil war) 1858 Ezra Warner of Waterbury Connecticut patented the first can opener. 1866 J Osterhoudt patented the tin can with a key opener that you can find on sardine cans

What year was commercial canning factory set up for the first canned goods in the British Army?

1813

Henry Evans

1846 invented machines that could manufacture tin cans at 60/hour

Pasteurization receives how many log reductions?

5 log process

D value example: 145F salmonella in chicken = 2 mins achieve a 7 log reduction

7 log reduction x 2 mins = 14 minute hold when food reaches 145F Given log reduction x given minute

Processes that Heat Prior to Packaging

Aseptic Fill method - under sterile conditions - most important food technology in 50 years . Liquid or pureed material is heated very quickly and pumped into chamber. Held for 20 seconds then pumped to cooling system. Pumped into a filling system where it is put into pre-sterilized containers Rapid heating and cooling provides bette quality and lower costs Single serve products of coffee creamer, juice products and milk products Hot pack or hot fill - foods heated to high temperatures rapidly. Filled into containers that are not sterile but are very clean . The foods are still hot. Food temperature destroys microorganisms. Used for high acid foods Low acid foods packaged like this are called pasteurized and stored in refrigeration Sous Vous Process Used in france/europe not approved by FDA Foods are vacuum packaged and heat processed some, but not really enough to kill C. Bacteriium. Cryovacing - 140F for up 24H in vacuum packaging Microwave Processing - home microwaves are unpredictable in their cooking. Developed mainly for use in seafood industry. Causes water molecules to oscillate commercial processes use pressurized chambers to enable higher temperatures to be reached Allows rapid heating but special equipment needed Sometime produce different product appearance

The pathogenic microorganisms with greatest heat resistance is _________ due to spores The ____ operation is designed to kill this microorganism at high levels

CLOSTRIUM BOTLULNUM Canning

Heat Transfer in Food

Conduction - heat moves from one particle to another by direct contact. Food does not move inside the container. No circulation or stirring occurs. Heat from outside to inside Convection - involves movement of food. Movement can be natural or mechanical leading to food circulation within the container. More efficient. Heated particles move upward. Radiation - particle movement causes heat (i.e. microwave) uses electromagnetic energy

1822 condiment canning factory

In Boston, MA. William Underwood, 1st recorded US cannery

Commercial Heat Processing types

Kills quality degrading enzymes Blanching - mild heat process - designed to kill quality degrading enzymes Pasterurization- kills disease causing bacteria (salmonella) Canning (retort) - high temperature of sealed containers in high temperature (closest to sterilization) Microwave processing Aseptic Packaging Several other operations - inferred, ohmic, radio frequency

Two types of organism that are most heat resistance in milk

Mycobacterium turboculosis - causes TB Coxiella burnetti - causes Q fever

History of Heat Preservation - Early 1800's __________ France discovered modern heat processing by preserving foods in sealed glass jars using boiling water

Nicolas Appert

Sterilization

No such things as complete destruction complete destruction of microorganisms (spores, bacteria) most extensive type of heating may lead to significant product changes and lower quality too extensive in most cases must reach 121Cl of wet heat for 15 seconds for every particle of food

1810 - ______invented metal can, which he used from the idea of who?

Peter Durand. Nicolas Appert

Blanching

Principle used to inactivate enzymes in foods (especially fruits and vegetables) before other processes such as freezing or canning Maintains quality but can lose some nutrients (water soluble vitamins) Two types of blanching - water and steam Destroys some microorganisms but that is not the purpose of Blanching

Commercial Heat Processing

Refers to controlled processes performed on large scale

Types of Heat Process

Retort - in package heat process Pasteruerization Batch (low temperature long time LTLT) - milk . 145F for 30 mins in a vat with milk agitation. Food leaves vat and is cooled before packaging . Destroys pathogens and enzymes. mainly used in dairy farms High Temperature Short Time (HTST) continuous process 161 for 15 seconds pump food through holding tube where milk will get the exact time/temperature treatment After heating milk is cooled and packaged Mainly used in milk and other foods Ultra High Pasteurization - UHT - shelf stable type of stuff - 280F for 2 seconds

Peter Durand

Took Nicolas Appert canning idea, instead of using glass, he used tin.

Heat Treatments (3 types)

What time/temperature combination is required to inactive the most heat resistant microorganisms in a particular food 2. heat penetration characteristics of a particular food including can or container (size, shape, material) 3. Food effects on heating (consistency, particles vs liquids, sugar/fat/starch/protein content) The most remote particles of a food in a batch or in a container must receive this time/temperature treatment to be effective

Underwood introduced what process in 1936

glass jars to steel lined tin cans with steam under pressure to shorten processing time and control spore growing bacteria Sporegrowing bacteria in cans could be identified by cans with bulges. Underwood created a process with MIT to prevent that 1895 - 1936.

12 D process

heat treatment that will give substantial margin of safety against C. botulinum

Why do we process heat?

it tastes better looks better more tender/palatble longer shelf life Kills all bacteria and disease microorganisms (primary reason we heat food)

Commerically Sterility (used all the time)

shelf stable cans, on the shelfs. Killed all the organisms that would make us sick, pathogens and toxic. Small number of resistant spores may survive but will not grow unless given special opportunities, e.g. can leakage Most canned and bottled products are commercially sterile and have shelf life of greater than 2 years 12 log reduction in Clostridium botulinum spores