The internet source for discussion and knowledge on pasteurization equipment, technology, and equipment selection for flash pasteurization, tunnel pasteurization, and used pasteurizers.

Great Brief on Processing Differences between Pasteurization and Homogenization

Friday, June 26, 2009




Pasteurization is by definition a balance. Boiling any product will surely kill the bacteria at the expense of also breaking down nutrients. The difference between UHT and HTST & Tunnel are that UHT is meant to Sterilize, while Flash and Tunnel are meant to pasteurize.
The values shown above utilitize Milk as the product to be treated. Ironically, UHT is a higher temperature and shorter time that HTST. Values can be adjusted slightly depending on the product for Tunnel and Flash processes.
Homogenization is not related to pasteurization. It is the process used to separate (generally milk) into cream and skim (non fat) milk. This is done by taking advantage of the natural separation which occurs during chilling.
Most importantly, tunnel pasteurization is the only process which pasteurizes both the product and the package.

Shelf Stability of Apple Juices and Ciders

Sunday, June 21, 2009


What is required by law to produce shelf stable juice or cider products? These markets are unique in the opportunity for small businesses to enter the market. Consideration must be taken to the microbial risks associated (i.e. E.Coli, etc.). Each producer needs to take into account the required mandates for production. These are covered in the FDA document: Guidance for Industry Juice HACCP Hazards and Controls Guidance First Edition.

A summary is that for each product and production facility there must be the microbe you identify as the "pertinent microorganism," which is the most resistant microorganism of public health significance that is likely to occur in the juice, e.g., E. coli O157:H7. The process used for production must consistently generate a minumum 5-log reduction of the "pertinent micro-organism."

One excerpt from the document:

4.2 Example of a Process for a Shelf Stable Juice
The National Food Processors Association states that a typical hot fill/hold process used for shelf stable juices might be to treat the juice at 90 degrees C (194 degrees F) for 2 seconds, followed by filling at 85 degrees C (185 degrees F) and holding for 1 minute at that temperature. Based upon research it conducted for E. coli O157:H7, Salmonella species (spp.) and Listeria monocytogenes in fruit juices, NFPA calculated that this typical process used for shelf stable juices would achieve a 50,000 log reduction for these pathogens without taking into account the cumulative lethality during the cool down period. (See reference to publication by Mazzotta in section V. C. 5.0).

A Second Example of a Process for a Shelf Stable Juice
If for reasons of carbonation or other considerations, the product were to be cold filled, juice or cider in glass jars could be treated with a fully regenerative tunnel pasteurizer. Temperatures of 162 degrees F for 30 minutes would be the recommended start point to be confirmed with laboratory tests focused on the "pertinent microorganism".

When deciding between tunnel and flash pasteurization, reference the other pertinent articles on this blog. As juice is a product with a large "kids" market, the ability to put "pasteurized" on the package, and state that the product was pasteurized "in the package" has been known to add commercial value.

Guide to Purchasing a Used Pasteurizer (Tunnel)

Monday, June 15, 2009

A used pasteurizer can be a great opportunity to offset capital costs. Studies show that internet searches on the topic of pasteurization have more internet searches for the words “used pasteurizer” than any other topic on pasteurization. While purchasing a used pasteurizer can be an opportunity, consider these points as the project progresses.


Used Pasteurizer: Tunnel

• Look for a unit made completely of stainless steel. Older carbon steel tunnel pasteurizers, and yes even flash units with carbon frames suffer from erosion.
• Consider the machines method of heating. The capital cost savings can be quickly paid back in steam, water, and electrical usage. Avoid units that are non-regenerative, coil driven, or direct steam injected. Remember that there is a significant value to condensate recovery!
• A poorly controlled or incorrectly sized pasteurizer will fight itself by adding cool water and steam, often times simultaneously.
• Machine size and zoning must be right for the machine to accomplish the process. This is not only the length, and width of the machine, but the speed of the belt, the flow rate of the water, and the heating characteristics of the product. Get professional confirmation that the sizing and zoning will match your production.
• How the machine is removed is a key factor in the re-assembly. If the machine has not been removed, consider being there or taking owenership of the removal process. This could mean the difference between your getting what’s in the picture above or the difference between a machine that leaks or doesn’t. It’s also an excellent way to begin to get to know the equipment and will make the re-assembly more straightforward.
• Take a hard look at the controls package. Remember, the shelf life stability of the product will be controlled by the machine. Ensure that there are clear electrical drawings. If there are not, or you’re confidence is not high enough comfortable, consider trashing the electrical panel and having another one designed and program built from scratch. Chart recorders are no match for todays technology.

For the areas where engineering support is needed… whether in the utility consumption, machine sizing, or electrical controls, call a competent new machinery manufacturer and ask for their help in engineering support. They will be glad to help. Contract them for the “hard parts” of the project. They will be glad to work with you in return for the ability to provide service to the machine, which may be something that needed to be considered anyway.

Feel free to write in for a list of available resources.

Pasteurizing Homebrew to Increase Shelf Life Stabilty

Friday, June 5, 2009



Why Pasteurize? Once the bottle is closed pasteurization will kill the microogranisms (including yeast) in the beer, cider, or wine. Microorganisms and yeast all have a "kill point" which is a product of temperature and time. Once those organisms stop "feeding" on the carbohydrates the product is "Stable" and thus its flavor is stable. Does the pasteurization process itself change the flavor? Experts say "Yes, but not dramatically". Seems natural if any process affects the product it affects the flavor.

This is what is called "vat pasteurization" or "immersion pasteurization". Turn your hot water heater to high for this, and find a sink, cooler, or tub that will hold the product desired. Pasteurization requires that an elevated temperature be held for a duration of time. So in this excercise, hot water must continually run into the "tank" at the same rate it is allowed to "leak". A home hotwater source is generally about 165F.

Put the product in the tub, sink, or cooler. Fill it with hot water (assumed to be 150F-160F). Once full, create a slight draining effect and continue to fill with hot water. For 12 oz bottles, keep the bottle in this state for approximately 45 minutes for 750 ml bottles keep the bottles in this state for approximately 60 minutes. A floating thermometer is always a good idea and confirming that the vessel is above 145F is a good idea.

Once the time has elapsed, remove the product from water and move directly into refrigeration for rapid cooling (i.e. remove all heat from the product).

Home pasteurizing in this way does not kill every flavor changing microorganism but kills most. At this point most products should maintain their flavor for roughly 8-12 months in an unrefrigerated environment. The "comeback rate" is a function of the temperature the product is stored at (i.e. growback rate at room temperature is higher than refrigerated). This process will consume roughly an hour to execute and will provide up to 12 months of flavor stability.

Part IV - Summary Results of Case Study - Flash Pasteurization Vs. Tunnel Pasteurization

Tuesday, June 2, 2009



Note; the following article is an excerpt from a (now) more complete article here.

Process Considerations

 All three options are capable to produce good biological stability for the Light Lager line

 May encounter technical difficulties with the Malta Beer production in Sterile Filtration and Flash Pasteurization
 Slow filtration throughput due to High viscosity (sugar concentration) – multiple stages of filtration needed
 High sugar/protein concentrations require high PU, and the flash pasteurizer plates may be scorched/baked, reduce pasteurization capacity and allow contamination point – high maintenance cost and potential damage to the flash pasteurizer

Sanitation Considerations

 Minimum changes required for Tunnel Pasteurization

 Sterile Filtration and Flash Pasteurization both require a “Clean room” and Aseptic Filler
 Aseptically maintained
 Positive pressurized (HEPA filter)
 Sterile bottles and crowns
 Additional QA personnel required

QA/QC: Sanitation

 Tunnel Pasteurization
 The whole product (beer, crown, bottle) are pasteurized
 No new issues to consider

 Sterile Filtration and Flash pasteurization
 Clean room needed – maintenance required
- Clean room sanitation and biological sampling
- Aseptic filler sanitation and biological sampling
 Biological stability control of the product
- Frequent bottled sample plating
(especially important for the Malta Beer)


QA/QC: Flavor

 Whenever there are changes in process, changes in flavor should be considered / controlled

 Sterile Filtration may strip flavors
 May be lesser an issue for the Light Lager line
 May severely affect the flavor profile of the Malta Beer
 Flash Pasteurization
 Potential minor flavor change for the Light Larger line
 May induce burning flavor into the Malta Beer

 Sensory tests need to be conducted