1 aseptic processing and packaging systems chapter 14 ( aseptic processing and packaging systems...

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ASEPTIC ASEPTIC PROCESSINGPROCESSING AND AND PACKAGINGPACKAGING

SYSTEMSSYSTEMSChapter 14Chapter 14

((21 CFR 113.40 Subpart g)

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IntroductionIntroductionIntroductionIntroduction• The primary objective of both conventional

canning and aseptic processing and packaging is to produce a commercially sterile product in a hermetically sealed, commercially sterile package

• Aseptic refers to a condition free of micro-organisms or to using methods and procedures that create and maintain a condition free of microorganisms

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IntroductionIntroductionIntroductionIntroduction• Bringing a commercially sterile

container and a commercially sterile product together and hermetically sealing to produce a commercially sterile finished product requires a processing and packaging system that creates and maintains conditions free of microorganisms – hence the term aseptic process and packaging

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IntroductionIntroductionIntroductionIntroduction• Commercial sterility is a condition

achieved by the application of heat (alone or in combination with other treatments) that renders the product, equipment and/or containers free of viable microorganisms of public health significance as well as those capable of growing in the food under normal non-refrigerated conditions of storage and distribution

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IntroductionIntroductionIntroductionIntroduction

• Aseptic processing and packaging requires the integration of equipment designed to• sterilize the product• temporarily store sterile product• Sterilize packages and bring the sterile

product and sterile package together in a sterile environment to form a commercially sterile, hermetically sealed package

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• Process establishment for aseptic systems must consider not only the sterilization of the product, the processing equipment, and the downstream piping, but also the sterilization of the packaging material and packaging equipment, as well as the maintenance of sterile conditions throughout the entire system

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• Commercial sterility must be maintained throughout the system, from the point where the product is heated to the discharge of hermetically sealed containers

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IntroductionIntroductionIntroductionIntroduction• Successful aseptic processing and

packaging of foods requires, as a minimum, the following conditions:• A pumpable product• Equipment that can be sterilized• Sterile product• Sterile packages• A sterile environment within the packaging machine

in which to bring sterile product and packages together and hermetically seal the packages

• Monitoring, recording, controlling critical factors• Proper handling of finished packages to maintain

container integrity

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ASEPTIC ASEPTIC PROCESSINGPROCESSING SYSTEMSSYSTEMS

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Basic RequirementsBasic RequirementsBasic RequirementsBasic Requirements

• Although equipment for aseptic processing system varies, all systems have common features• A pump to move product through the

system and control flow• Equipment designed to heat the product• A hold tube designed to keep product at or

above process temperature for the time needed for sterilization

• Equipment designed to cool the product to filling temperatures

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• Common features (continued)• Equipment designed to store sterile, cooled

product before filling• A method for cleaning all equipment prior

to production and a method for sterilizing all equipment down stream from the heaters

• Equipment and methods designed to maintain sterility during production

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• Common features (continued)• Control and monitoring devices to

accomplish and document equipment sterilization, product sterilization, maintenance of sterility, and prevention of non-sterile product from reaching the packaging equipment

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Aseptic Processing and Packaging System

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Aseptic Processing SystemCourtesy of Tetra Pak

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Pre-sterilizationPre-sterilizationPre-sterilizationPre-sterilization• Production of sterile product cannot be

assumed unless the processing system has been sterilized before starting production

• Sterilization cannot be assured unless the system is thoroughly cleaned

• Cleaning is usually accomplished using a Clean-In-Place (CIP) system designed as an integral part of the processing system

• CIP system provides cleaning of product contact surfaces without having to do disassembly

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Pre-sterilizationPre-sterilizationPre-sterilizationPre-sterilization• Prior to production, most processing

systems circulate hot water for a sufficient length of time to sterilize the equipment

• Water, usually heated by the system heat exchanger to a temperature significantly higher than the product processing temperature, is pumped through all down stream piping and equipment up to and generally past the filler valve on the packaging unit

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Pre-sterilizationPre-sterilizationPre-sterilizationPre-sterilization

• All product contact surfaces downstream from the product heater must be maintained at or above a specified temperature by continuously circulating the hot water for a required period of time

• The cooling media in the cooling equipment is usually drained off so that the cooling equipment can achieve the needed temperature

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• After the system has been at temperature for the specified time, the system will continue to circulate the water but the cooling equipment is activated and all equipment downstream will be cooled down to normal operating temperatures

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• To control system sterilization properly, it is necessary that a sensor be located at the coldest point(s) in the system

• Generally this is sensor is located at a point most distant from the heaters

• Timing of the sterilization cycle starts when the proper temperature is obtained at this remote location

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Flow ControlFlow ControlFlow ControlFlow Control

• Product must flow through the hold tube at a uniform and constant rate so the fastest moving particle of food and/or fluid stream receives at least the minimum amount of heat for the minimum amount of time specified by the scheduled process

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Flow ControlFlow ControlFlow ControlFlow Control

• The minimum time of the fastest moving particle is a function of the flow characteristics of the food, the hold tube configuration, and how fast the product is flowing

• Since the flow characteristics of the product are fixed, as is the configuration of the hold tube, control of time is determined by the pump pushing the product through the system

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Flow ControlFlow ControlFlow ControlFlow Control• Since the pump is controlling the time,

it’s called the timing or metering pump• Timing pumps may be fixed rate or

variable speed• The speed of the fixed rate pump cannot be

changed without dismantling the pump• Variable speed pumps are designed to

provide flexibility and allow for easy rate changes

• When a variable speed pump is used, it shall be protected from unauthorized changes – lock or notice OK

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Product HeatingProduct HeatingProduct HeatingProduct Heating• Product heater brings the product up

to or higher than the minimum temperature specified

• The most common equipment utilize thermal techniques - heat transfer from steam or hot water to heat the product• Another technique, Ohmic heating,

passing an electric current through the product, has been used

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Product HeatingProduct HeatingProduct HeatingProduct Heating

• For thermal techniques there are two major categories of product heaters• Direct heating• Indirect heating

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•Direct Heating - Direct contact between the heating medium (steam) and the product

• Direct heating systems one of two types• Steam Injection – introduces steam

into the product stream• Steam Infusion – introduces product

through a steam-filled chamber

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Steam Injection

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Steam Infusion

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•Direct Heating • These system are limited to homo-

geneous, low viscosity products

• One advantage is very rapid heating which minimizes organoleptic changes • Problems of fouling or “burn on” are

reduced

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•Direct Heating • A disadvantage is the addition of

water•From condensation of steam in the

product

• Depending on the product, the water may need to be removed – during cooling

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•Direct Heating • Steam used for direct heating must

be culinary quality and must be free of non-condensable gases

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• Indirect Heating • Physical separation between the

product and the heating medium• Heat is transferred from the heating

medium to the heat exchanger to the product• Three major types of heat exchangers

•Plate•Tubular•Scrap-surface

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• Indirect Heating – Plate heat exchangers• Used for homogeneous liquids of

relatively low viscosity• The plates serve both as a barrier and

a heat transfer surface – product on one side heating medium on the other• Each plate is gasketed, and a series of

plates are held together in a press•Number of plates can be adjusted to

meet specific needs

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Plate Heat Exchanger

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• Indirect Heating – Tubular heat exchangers• Used for homogeneous liquids of low to

medium viscosity• Concentric tubes or tubes in a chamber

serve as heat transfer surfaces •product flows through the inner tube of the

double-tube style and through the middle tube of the triple-tube style

•Heating medium in the other tube(s) flows in the opposite direction to the product

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Tubular Heat

ExchangerA = Triple

B = Double

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• Indirect Heating – Tubular heat exchangers• In a shell and tube heat exchange, the

tube is coiled inside a shell• Product flows through the tube while

the heating medium flows in the opposite direction through the shell

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Shell and Tube Exchanger

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• Indirect Heating – Scraped-surface HE• Normally used for processing more

viscous products• Consists of a mutator shaft with scraper

blades concentrically located within a jacketed, insulated, heat exchange shell • The rotating blades continuously scrape

product off of the inside wall of the tube• This scraping action reduces buildup

of product and “burn on”

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Scraped Surface Heat Exchanger

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Product HeatingProduct HeatingProduct HeatingProduct Heating• Product-to-product Regenerators • Plate or tubular heat exchangers with

product flowing on both sides of the plates or through both sets of tubes• This allows the heat from hot sterile

product to be transferred to the cool, incoming, non-sterile product • Yields significant energy and cost

savings from “recycling” the heat from sterile product

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Product HeatingProduct HeatingProduct HeatingProduct Heating• Product-to-product Regenerators • When used, it shall be designed,

operated and controlled so that the pressure of the sterilized product is at least one psi greater than the pressure of any non-sterilized product• This ensures that any leakage will be

from sterilized product into non-sterilized product • An accurate differential pressure

recorder-controller shall be installed

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Hold TubeHold TubeHold TubeHold Tube• Once the heaters have brought the

product up to the required processing temperature, the product needs to be held at that temperature for the time specified in the scheduled process

• The process time, or residence time, is the time the fastest particle flowing through the hold tube remains in the hold tube• Metering pump determines flow

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Hold TubeHold TubeHold TubeHold Tube

• Requirements• Upward slope in the direction of

product flow of 0.25 inch per foot

• If the hold tube can be taken apart, a means must be provided to make sure that…• All parts are replaced so the tube is not shorter

or different in diameter• When reassembling the tube, the gaskets do not

protrude - The tube interior should be smooth and easily cleanable

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• Requirements• No condensate drips on the tube, and it

should not be subjected to drafts of cold air

• External heat shall NOT be applied

• Product in the hold tube must be maintained under pressure sufficiently above the vapor pressure at process temperature to prevent “flashing”

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• Product temperature shall be monitored at the outlet of the hold tube.• A sensor shall be installed in the hold tube

outlet (cooler inlet)

• This serves as the instrument of record, like the indicating device on retort systems

• A recording device sensor shall also be located at the hold tube outlet to record temperature

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Product CoolingProduct CoolingProduct CoolingProduct Cooling

• Product flows from the hold tube into a product cooler

• Indirect heating systems generally cool product using the same type of heat exchanger used to heat the product

• Cooling may also include the use of a product-to-product regenerator or a product-to-water-to-product regenerator

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Product CoolingProduct CoolingProduct CoolingProduct Cooling

• Those systems using direct heating will typically utilize a flash or vacuum chamber to cool product• Hot product exposed to a reduced pressure

atmosphere within the chamber will result in the product boiling or “flashing”

• The product temperature is lowered and a portion or all of the water added to the product during heating is removed by evaporation

• May cool further in indirect systems

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Maintaining SterilityMaintaining SterilityMaintaining SterilityMaintaining Sterility• After the product leaves the hold tube it is

sterile and subject to contamination

• Simplest and best way to prevent contamination is to keep the product flowing and pressurized

• The back pressure device maintains the entire product system under elevated pressure

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Aseptic Surge TanksAseptic Surge TanksAseptic Surge TanksAseptic Surge Tanks

• Used to hold sterile product prior to packaging

• Can provide flexibility• Receive product if processing system is

faster than the packaging system

• Processing and packing carried out independently with all product going into the tank and then fill later

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Aseptic Surge TanksAseptic Surge TanksAseptic Surge TanksAseptic Surge Tanks

• A disadvantage is it violates the basic premise of maintaining sterility – “keep it moving”

• This is overcome by utilizing the other basic premise – “keep the system pressurized”

• Sterile air or gas used to provide positive protective pressure and aid in the displacing the tank’s contents

• Pressure must be monitored and controlled

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Automatic Flow DiversionAutomatic Flow DiversionAutomatic Flow DiversionAutomatic Flow Diversion• May be used to prevent the possibility

of potentially non-sterile product reaching the sterile packaging equipment

• The flow diversion valve should automatically divert if a deviation occurs• Temperature at the hold tube dropping below the

scheduled minimum• Insufficient pressure differential in the regenerators• The packaging unit dropping below minimum

operating specifications

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ASEPTIC ASEPTIC PACKAGINGPACKAGING SYSTEMSSYSTEMS

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• Aseptic packaging systems are designed to combine sterile product with a sterile package resulting in a hermetically sealed, sterile product

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Basic RequirementsBasic RequirementsBasic RequirementsBasic Requirements• Features common to all aseptic

packaging systems• Create and maintain a sterile environment in

which packages and product can be brought together

• Sterilize the product contact surfaces of the package

• Aseptically fill the sterile product into the sterilized package

• Produce hermetically sealed containers• Monitor and control critical factors

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Sterilization Sterilization Agents for Equipment and Agents for Equipment and

PackagePackage

Sterilization Sterilization Agents for Equipment and Agents for Equipment and

PackagePackage• Used in aseptic packaging units to

sterilize the package material and the internal equipment surfaces to create a sterile packaging environment

• Generally involve• Heat• Chemicals• High-energy radiation• Combinations of these

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Sterilization AgentsSterilization AgentsSterilization AgentsSterilization Agents

Heat• Heat is the most widely used method

of sterilization • Steam or hot water is commonly used

and referred to as "moist" heat• Superheated steam or hot air also

used in certain situations and is referred to as "dry" heat

• Dry heat is much less effective than moist heat at the same temperature.

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Sterilization AgentsSterilization AgentsSterilization AgentsSterilization AgentsChemical agents - Hydrogen Peroxide• Often used in combination with heat

• FDA specifies that a maximum concentration of 35 percent may be used for food contact surfaces.

• FDA requirement: No more than 0.5 ppm hydrogen peroxide may be present in tests done with distilled water packaged under production conditions

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Sterilization AgentsSterilization AgentsSterilization AgentsSterilization Agents

Chemical agents - Other• Peroxyacetic acid or PAA• Widely used around the world for low-

acid and acid food aseptic applications

• High energy radiation, UV light, gamma or electron beam radiation could be used alone or in combination with existing methods

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Aseptic ZoneAseptic ZoneAseptic ZoneAseptic Zone

• Aseptic zone is the area within the aseptic packaging machine that is sterilized and is maintained sterile during production• Area in which the sterile product is filled and

sealed in the sterile container

• The aseptic zone begins at the point where the package material is sterilized or where pre-sterilized package material is introduced into the machine

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• The area ends after the seal is placed on the package and the finished package leaves the area

• All areas between these two points are considered part of the aseptic zone.

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• Prior to production, the aseptic zone must be sterilized to a condition equivalent to that achieved on the packaging material or other product contact surfaces

• The sterilant(s) must be uniformly effective and the application controllable throughout the entire aseptic zone.

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• Sterility can be protected by maintaining the aseptic zone under a positive pressure of sterile air or other gas

• As finished containers leave the sterile area, sterile air flows outward preventing contaminants from entering the aseptic area

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Production of Aseptic Production of Aseptic PackagesPackages


• A wide variety of aseptic packaging systems are in use today

• Categorized by package types:• preformed rigid and semirigid containers• webfed paperboard laminates and plastic

containers• partially formed laminated paper

containers• thermoform-fill-seal containers• preformed bags or pouches• blow-molded containers

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• Aseptic packaging systems may sterilize containers by a variety of means• metal cans - superheated steam• preformed plastic cups - hydrogen peroxide

and heat or by saturated steam• paperboard laminates - by hydrogen

peroxide and heat or hydrogen peroxide and ultraviolet irradiation

• plastic pouches or bags - gamma irradiation, heat of extrusion or hydrogen peroxide

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• Whatever equipment, sterilants or packaging materials are used, the monitoring and control of critical factors will be vital to successful operation.

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IncubationIncubationIncubationIncubation• Holding of a representative sample of

finished product at a specified temperature for a period of time for the purpose of permitting or stimulating the growth of microorganisms that may be present

• Routine product incubation programs are recommended as a check on the overall quality and sterility of aseptic products.

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IncubationIncubationIncubationIncubation• Incubation tests should be conducted

on a representative sample of containers of product from each packaging code

• Records of the incubation tests should be kept

• While useful as a verification tool, incubation should not be viewed as a substitute for good manufacturing practices

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Record RequirementsRecord Requirements

• All critical factors specified in the scheduled process shall be measured and recorded at intervals of sufficient frequency to ensure that they remain within the limits specified

• These intervals should not exceed 15 minutes

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Record RequirementsRecord Requirements• Depending on the system, some

additional process parameters which may need to be monitored and recorded include:• temperature at the hold tube outlet• differential pressure of the product-to-

product regenerator• product flow rate• sterile air pressure of aseptic surge tank• proper performance of steam seals• sterilization media temperature and flow

rate• container flow rate• sterilization cycle times and temperature

1 aseptic processing and packaging systems chapter 14 ( aseptic processing and packaging systems...

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