Monthly Archives: July 2019
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Why Tunnel Pasteurize new and emerging beverages?

Food Safety in beer was once focused on undesired foreign materials and debris found in individual beverages cans and bottles. While still important, Food Safety in beverages today is mostly microbiological because breweries have moved far beyond producing only traditional beers.

We all know of examples of production and beverage sales environments where products are made, sold very quickly and in a tight geography…premises such as brewpubs and local neighborhood breweries which can offer a promise of freshness and competent storage of product between production and sale/consumption. But for any volume, sales must extend further, and quality must be assured for longer timeframes and across varying real-world conditions.

Approximately 70% of beer spoilage cases result from contamination by lactic-acid bacteria, which produce flavors considered to be undesirable in most beer styles. The remaining spoilage cases are caused by a range of wild yeasts, as well as aerobic and anaerobic bacteria, that are present in the brewery environment and can carry-over to the beer if rigorous hygiene is not maintained.

Microbial inactivation

Harmful pathogens are not able to grow in beer due to several microbiological ‘hurdles’ such as alcohol, low pH, low nutrient content and the presence of growth inhibitors such as isomerized hop acids.

In continued evolution within breweries and beverage plants of all sizes, beverages are coming from breweries these days that would not have been twenty years ago. We see the emergence and growth in popularity of novel alcoholic beverages that may contain added sugar, flavorings and colorings. We see alcoholic beverages based on extremely low malt- inclusion rates, the product being fermented ‘sugar brews’. Breweries today produce beers mixed with fruit juices, and natural sodas, and low alcohol, sweetened beverages appealing to non-traditional beer drinkers. We’re also seeing novel cannabis-isolate containing hybrid beverages, These new drinks offer fewer naturally-inherent microbiological hurdles for spoilage organisms.

Due to novel ingredients previously not involved in production, beverages need to address concerns over germination of spores, and the growth of pathogens and other spoilers not routinely encountered in the brewing industry. The pasteurization parameters to destroy the vegetative cells and spores of Bacillus spp. are higher than what is normally accepted as adequate for milk pasteurizing…. 170 deg F at ten minutes hold.

The most common spoilage organism of tomato juice, B. coagulens produces lactic acid in package if not destroyed. In pineapple nectar, Byssochlamys nivea is a thermal resistant filamentous fungi (mould) with mycotoxin-producing potential that needs high sterilizing temperatures equivalent to tomato juice. Not every alternative product requires as aggressive a pasteurizing regime, of course. There are some new products, such as cold-brew coffees, that actually should go through much higher retort temperatures because the individual coffee beans, when dropped on the ground can make contact with botulism. Basic beer pasteurization does help cold-brew coffees and other novel beverages in an essential way:

Coffee with residual sugar is prone to refermentation or spoilage and can easily become a problem. Canned and fermenting coffee creates alcohol and carbon dioxide. That CO2 will continue to build and the can will explode or, in the case of a bottle, the cap/crown might pop off.

As a matter of fact, any beverage that is sweet or semi-sweet, has residual sugar…which is prone to refermentation in the closed package. The challenge for a retort temperature approach is readily seen in low acid products like banana and kiwi puree. Often, to inactivate spores and natural enzymes, a temperature much be reached that changes the color of the product being pasteurized. For example, a standard retort thermal treatment of these purees is at 130-135°C (266-275 F); due to this temperature the puree color changes to pink for banana and to brown for kiwi at 90-95°C (194-203 F). 

The only potential alternative to applying a retort regime is heavy pasteurization, storage and shipping of finished goods at refrigerated temperatures, and possible use of the common preservatives used by soft drinks manufacturers: potassium sorbate and sodium benzoate, in the event that the beverage is alcohol-free and non-acidic in nature. However, using preservatives is contrary to the “Clean-label” movement that seeks to eliminate preservatives, artificial flavors and coloring in food and beverage products.

New beverages

At one point in American brewing history, many breweries were making malt-based coolers, sometimes referred to as alcopops and later as FMBs. Some of the beverages used a natural dairy-based clouding agent (“Cloud”) or non-dairy based to make milky Pina Colada flavored drinks. The palette of available natural clouding agents today is much broader.

Non-alcoholic plant-based beverages might be made up of about 90% water, sugar, flavoring …but plants parts have constituted the main raw materials in these beverages…and source of microbiological concern. Soybeans are used for the production of soymilk, rhizome of ginger plants for ginger beer, sorghum or other grains, sweet potato extracts, water extracts of flowers (such as roses or hibiscus) and leaves (especially tea leaves). Soymilk contains 26.25% protein, 22.24% oil, 21.55% total solids, 4.55% Ash, 24.4% carbohydrate .

Ginger powder has 5.21% ether extract, 61.21% carbohydrate, 8.89% protein. 8.47% ash and 1.70% crude fiber. Common microbial challenges for soymilk would be Pseudomonas spp., and for ginger beer, Lactobacillius, Leuconostoc, Bacillus, Staphylococcus, Candida and Saccharomyces. These species can be addressed in a tunnel pasteurizer.

So what other kinds of beverages benefit from tunnel pasteurization? Novel beverages including natural and botanical soft drinks, flavored malt beverages, novel alcoholic beverages which may or may not be carbonated, fruit-inclusive drinks, alcoholic spritzers based on neutral alcoholic bases brewed in breweries, canned cocktails, innovative hybrid beverages.

The process of pasteurization guarantees stability of the packaged product without refrigeration. In a PRO Engineering design, it is carried out in extensively proven-design pasteurization tunnels with various heating, retention, and cooling zones, in which heat transfer occurs through a water film formed by aspersion on the package. The process is dimensioned in “Pasteurization Units” (PU), in which 1 PU is equivalent to 1 minute at 60 ºC,

Raising the pasteurization temperature to 68 ºC will yield 14 PU if held for 1 minute, and a temperature of 77 ºC and holding 1 minute realizes 268 PU. By changing the hot water spray setpoints and dwell time within the pasteurizer zones, a PRO Engineering pasteurizer can be designed, built and tuned to deliver 5 to 2500 PUs, depending on what the product in the individual package would require. PRO offers a batch-pasteurizer small footprint system for startups and exploratory projects, and all scales of continuous flow-through tunnel pasteurizers that can accommodate different packaged product volumes and packages (bottles or cans). Instrumentation such as a traveling tunnel PU monitor can be run through the pasteurizer to document adherence to target pasteurization parameters.

In the brave new world of alternative adult beverages, with alcohol or without, a batch- or tunnel- pasteurizer engineered for purpose by PRO and sized so as to meet line speed requirements for throughput represents how quality is robustly assured once the products leave the production facility.

Authored by Jaime Jurado

Past President-MBAA

(Master Brewers Association of the Americas)

https://www.linkedin.com/in/jaimejurado/

https://independent.academia.edu/JaimeJurado

Sponsored by Ed Michalski, CEO PRO Engineering and Manufacturing, Inc

PRO and Manufacturing, Inc has been providing equipment and engineering services to the beverage industry for 42 years. Contact Ed Michalski, CEO at: (414) 362-1500, [email protected]

ABOUT US:
PRO Engineering and Manufacturing was established in 1977 by Ed and Dave Michalski as a steel fabrication shop. For more than 40 years, PRO Engineering and Manufacturing, Inc. has been delivering solutions for beverage product shelf stability and consumption safety. As leading innovators in post-fill pasteurization, our skilled team offers the best in high-quality pasteurization equipment.

CONTACT US:
Phone: 414-362-1500 | Email: [email protected]

The Role of The Tunnel Pasteurizer: How Safe is Safe?

Creating and producing beverages are important to our lives and our livelihoods. As professionals, we are vigilant about food safety risks and taking very possible step to reduce as much as possible, conditions which create opportunity for problems.

The microbiological status of a packaged beer, especially one destined for a distant market, is of prime concern  and a brief Google browse shares, “the only satisfactory microbiological test is to pass at least 100 ml of beer through a 0.45 micrometer membrane, then plate the membrane on media (such as MRS or other media to be detailed) under conditions (for instance anaerobic at about 25° C) capable of detecting the target organisms in low number”.

Microbiological Media

As much as we would wish, a study of a beer samples under a microscope doesn’t work. Release of beer to the trade should await evaluation of its microbiological status, and it is possible, after sufficient time, to release products prior to having microbiological results, after ample opportunity to determine how ‘clean’ the tunnel pasteurized beer/beverage is. Some situations dictate that the packaged product is always held until complete micro release. The essential requirement of evaluation of efficacy is to carefully study a package of beer before it is pasteurized and after a package of the same beer batch has been pasteurized. Organisms are exposed to heat and the numbers surviving before and after treatment are determined. Viability is judged from the ability to multiply (to produce microcolonies).

Hsu’s Lactobacillus and Pediococcus (HLP) media can be employed to screen for common beer spoilers, while selecting against other organisms, such as yeast, gram negative bacteria and aerobic microbes (1). Other media include Lee’s multi-differential agar, Raka-Ray lactic acid bacteria medium, lysine medium, Lin’s wild yeast differential medium, Barney-Miller brewery medium, De Man Rogosa Sharpe medium, MYGP + copper medium, CLEN medium for wild yeast. The respected DIFCO Manual lists brewery-specific microbiological media (and their composition) including: Orange Serum Agar, UBA (Universal Beer Agar), Wort Ager, WL Nutrient Medium (Wallerstein Labs), WL Nutrient Broth, WL Differential Medium, YM Agar (Yeast Malt Extract), YM Broth. There are reported advantages to using various plating media.

For example, UBA supports growth of more varieties of lactic acid bacteria and yields larger quantities of these colonies in a shorter time, and it is a selective medium because within it, there is beer. Growth of microorganisms that have adapted themselves to thrive in breweries are detected.  The presence of hop constituents and alcohol eliminates the growth of many airborne pathogens. UBA supports growth of lactobacilli, pediococci, acetobacter and yeast strains robustly. Actidione at a level of 1 microgram per ml (1 ppm) is incorporated when samples containing yeast are cultured.

Temperatures to denature organisms and spoilage patterns

Industrial microbiologists have characterized the optimal temperatures for many species, i.e. brewing yeast 55 deg C;Moulds 65-80 deg C depending on species; Clostridium species (incl botulininum) 82-100 deg C depending on species.

The spoilage patterns of beer and ale  can be classified into four groups: ropiness, sarcinae, sourness and turbidity. Ropiness can be caused by Acetobater, Lactobacillus,  Pediococcus cerevisiae and Gloconobacter oxydans (formerly Acetomonas). Sourness arises from  Acetobacter spp. (which oxidize ethanol to acetic acid). Turbidity (and off-odors) in beer  may be caused by Zymomonas  anaerobia and several yeasts  such as Saccharomyces spp. In 1978, Coors Golden isolated Pectinatus cerevissphilius, which was then reported in other countries. Sarcinae is caused by P. cerevisiae, which will manifest a honey aroma and diacetyl flavor.

Packaged beer is susceptible to Saccharamoyces diastaticus, which can utilize dextrins in the beer which normal brewer’s yeast could not metabolize.

When this author worked in helping determine global tunnel pasteurization standards for one international brewing group, it was decided that the rate of under-pasteurized packages could not be less than one per 10,000 packages…which was the standard maximum-acceptable leaker rate at the time for the little milk boxes by Tetra-Pak used for school lunches (an interesting and completely unrelated comparator).

Using the Crystal Ball Monte Carlo add-on to MS Excel, it required a pasteurization target of 21 Pasteurization Units (PUs) to assure that the no more than 1 per 10,000 packages could be assured…when the real target was 15 PUs. This is the scrutiny that packages shipping all over the world require.

Yet it’s a different level of assurance required for beverages staying within a country and within a ‘normal’ shelf life. The simple question of “how safe is safe?’ relies on honest evaluation of what are valid criteria and the life of the packaged beverage after it leaves the brewery or beverage plant finished goods warehouse.

PRO Engineering can refer clients to specialized, certified, microbiological testing labs to help determine appropriate pasteurization levels, and a PRO pasteurizer can be configured to offer different pasteurization regimes. A fully-fermented alcoholic spritzer with flavors and no added sugar may require lower pasteurization than a barrel-aged beer. This author was fortunately in a large brewery setting with voluntary microbiological testing of pre- and post-pasteurized samples, when it was determined that 8 PU was a good target for a PRO tunnel pasteurizer. As mentioned, expert labs are available for confidential reporting and validation of acceptable post-pasteurization packaged beer and beverages.

What is desired is ‘non-detectable’ or  “less than 1” CFU/ml for aerobic bacterial testing, anaerobic bacterial testing, and yeasts and molds.

Tunnel pasteurization is a great means to achieve log-reductions of organisms that we don’t want in our beverages, a last defense bestowed on the beverages before they leave the facility. However, GMP and excellent cleaning and sanitation of all processes and unit operations (in bulk, in transport, and in packaging) prior to pasteurization are mission-critical to any ‘belt & braces’ approach to beverage quality assurance. The same goes for establishing an in-house microbiological testing lab. Regular and rigorous validation of microbiological status of packaged product for each batch is an expectation borne from prudence and the commitment to beverage quality assurance.

Authored by Jaime Jurado

Past President-MBAA

(Master Brewers Association of the Americas)

https://www.linkedin.com/in/jaimejurado/

https://independent.academia.edu/JaimeJurado

Sponsored by Ed Michalski, CEO PRO Engineering and Manufacturing, Inc

PRO and Manufacturing, Inc has been providing equipment and engineering services to the beverage industry for 42 years. Contact Ed Michalski, CEO at: (414) 362-1500, [email protected]

ABOUT US:
PRO Engineering and Manufacturing was established in 1977 by Ed and Dave Michalski as a steel fabrication shop. For more than 40 years, PRO Engineering and Manufacturing, Inc. has been delivering solutions for beverage product shelf stability and consumption safety. As leading innovators in post-fill pasteurization, our skilled team offers the best in high-quality pasteurization equipment.

CONTACT US:
Phone: 414-362-1500 | Email: [email protected]

Special Beers: The Case for Pasteurization

“It doesn’t taste like what we wanted it to” was the quote used at a recall of a Bourbon-barrel aged beer that was infected with alcohol-tolerant Lactobacillus acetotolerans, a souring bacteria.

American brewers have pushed boundaries of traditional brewing with the development of barrel-aged beers, with previously-used wine barrels, bourbon and sprits barrels, and with installation of foeders (wooden beer tanks) in their cellars. Beers no one imagined 20 years ago are finding their fans and making names for the breweries that produce them.

Over 100 years ago, it was only the British who used unpitched wooden beer casks, and the special flavors of Brettanomyces were prominent in many ales of the times. In continental Europe and in North America, the use of pitched beer casks, (casks lined with a flamed-on resin) (a kind of natural plastic with a very mild taste and aroma),  prevented beer from contacting wood and offered a smooth and cleanable surface.

Spirits casks expose the contents to direct wood surface contact. The uneven surfaces and spaces (pores within the wood) offer surfaces for microbial adhesion and colony growth. And with the fact that the surfaces are no longer flooded under spirits, one expects to find species including Zymomonas, Acetic acid bacteria, Candida, Zygosaccharomyces etc. present. 

Even typical ‘gut’ bacteria are favored by high concentrations of potential prebiotic components like arabinoxylan, beta-glucan and Maillard products like melanoidins (1). And many brewers these days have opened Pandora’s box for wild inoculations and spontaneous fermentation processes that allow them to express their terroir… microbes represent the new terroir.

Oak barrels are porous and air and microbes can be transported in and out. And the number of breweries using open-top coolships to cool wort in their brewhouses is impressive.

It should be clear that putting any beer, even if high-alcohol and high-hopped, in a cask and ageing it inside the cask, will inevitably bring microbiological challenges. Brewers are taught well on the antimicrobial properties of hops, but a second style of beer presents new microbiological challenges…

The growth of dry hopping as a brewing technique (adding hops cones, pellets, or powder directly to fermenting or already- fermented beer) naturally leads to rogue microbes gaining a new foothold in bulk beer.

Belgian brewers flavor their lambics with cherries and raspberries to make kriek and framboise, and these classic styles served as inspiration for countless North American breweries. Innovative beverages based on natural cereal and berry products have gained consumer attention and may open new opportunities for the breweries.

And the now-common practice of including loads of fruit in beers to deliver special flavors increases opportunity for undesired microbes to enter precious beer, often via species found on the skins of fruits. “Fruit” is a broad term with so much variety and also the form of the fruit. It is not uncommon for American breweries to add 8-25 lbs of fruit per barrel, and quite frequently, the addition is on the cold side.

Saccharomyces cerevisiae var. diastaticus is a natural variant of brewer’s yeast Saccharomyces cerevisiae. While cultured yeasts are essential for beer production, wild yeasts including S. diastaticus allow for a secondary fermentation in tank or in final package. Other wild yeast species of concern include Debaromyces, Brettanomyces Dekkera, Pichia, Hanseniaspora, Kluyveromyces, Torulaspora, Williopsis (2). And different fruits can bring in mycotoxins such as Ochratoxin A and Patulin (3).

Yeasts and vegetative cells of bacteria are typically very sensitive to heat; Yeast D-values (an indication of death rate) rarely exceed 1 min at 55 °C…but Shearer et al. (2002) did find a S. cerevisiae showing D values of 13 s at 71.1 °C in apple juice. Yeasts and vegetative cells of bacteria are typically very sensitive to heat (Stratford 2006). Yeast D-values rarely exceed 1 min at 55 °C.

Vegetative cells of beverage-spoiling microbes are usually more thermotolerant than bacterial pathogens or protozoans (Tribst et al. 2009, Lawlor et al. 2009). Shearer et al. (2002) found S. cerevisiae showing D values of 13 s at 71.1 °C in apple juice. Yeast ascospores can have 30–350 x higher thermotolerance compared to vegetative cells.

For example, D60 °C values of 7–22 min have been reported for asci of S. cerevisiae (3). A heat resistant Pediococcus sp. required 16 s heating at 71.1 °C for 5-log reduction in a simulated apple cider (Piyasena et al. 2003). Pasteurization treatments used in the beverage industry are usually sufficient to inactivate all species of concern, and most enzymes which otherwise could be adding fermentable sugars into the packaged product over time.

Many things occurring in the brewing processes are not 100% under control of the professionals. Packaging is. There is a mission-critical component within packaging that serves as our last layer of protection on beer that will soon leave to the wide world.

By virtue of applying heat within the contents of the already-sealed can or bottle, a PRO Pasteurizer is a proven means to offer long-term shelf-life stability with no impact on integrity of the package. A gentle passage under the water sprays in the pasteurizer, controlled heating in the PRO Single Zone Batch Pasteurizer or heating, then cooling in the PRO Triple Zone Batch Pasteurizer or a PRO Tunnel Pasteurizer, of the individual package contents… can result in confidence and security in the packaged beer.

As breweries in the USA increasingly move from the traditional can liners to ‘BPA- non-detectable’ materials applied to can interiors at their manufacturing plants by waterborne styrene-acrylic spray, waterborne non-BPA epoxy spray, or waterborne polyolefin dispersion spray, there have been no indications of de-laminations so adherence is the same as existing, proven liners.

And though it is true that sleeved cans (where a ‘brite’ (or unpainted can has its label heat-shrunk on the can body)  does temporarily ‘relax’ while the can is in the pasteurizing zone, this author has seen many examples where there is no evidence of any concern, no occurrence of water bubbles under the sleeve… but it can occur so prudence in qualifying sleeved cans from the sleeving service providers out there is called for.

Authored by Jaime Jurado

Past President-MBAA(Master Brewers Association of the Americas)
https://www.linkedin.com/in/jaimejurado/
https://independent.academia.edu/JaimeJurado

Article References: 

  1. https://lib.ugent.be/fulltxt/RUG01/002/482/227/RUG01-002482227_2018_0001_AC.pdf
  2. http://nik.waszczak.com/wp-content/uploads/2015/04/Microbiological-stability-of-beer.pdf
  3. https://www.vtt.fi/inf/pdf/tiedotteet/2011/T2599.pdf

ABOUT US:
PRO Engineering and Manufacturing was established in 1977 by Ed and Dave Michalski as a steel fabrication shop. For more than 40 years, PRO Engineering and Manufacturing, Inc. has been delivering solutions for beverage product shelf stability and consumption safety. As leading innovators in post-fill pasteurization, our skilled team offers the best in high-quality pasteurization equipment.

CONTACT US:
Phone: 414-362-1500 | Email: [email protected]

Tunnel Pasteurization Process for BrewMasters & Their Beer

Pasteurization is an important unit operation in beer processing that inactivates the spoilage microorganisms present in beer thereby extending its shelf life. Pasteurization is the reduction of microorganisms by heating to a limited temperature and holding at that temperature such that there will be minimum effect on physical stability and flavor and a maximum extension of biological stability.   

When the effect of pasteurization on the microbiological and sensory quality of white grape juice and wine was investigated by a UC Davis team, heat treatment of less than 3 Pasteurization Units (PUs = minutes at 60°C or equivalent) was sufficient to reduce 106 cells/mL of Saccharomyces cerevisiae and Hansenula anomala added to Chenin blanc juice to an undetectable level (1). 

Most brewers in the world pasteurize beer, including many craft breweries. The organisms which cause the most difficulty in the brewing industry today are lactobacillus, pediococcus and wild yeast. These are not pathogenic organisms but can cause turbidity and poor taste in beer.  

In order to insure complete pasteurization of beer, the temperature of the beer at the so-called “cold spot”, which is 1/4″ from the bottom of the center of the can or bottle, must reach at least 140° F. for a period of time to produce a specified number of pasteurization units (P.U.). It also is desired to pasteurize at the lowest possible peak cold spot temperature (above 140° F.) to avoid overheating the rest of the package contents, because the temperature of the package gets higher as one goes from the cold spot to the top of the package. 

Today’s brewery has several options when making decisions about long–term stability of its beers. 

Sterile filtration can fail, and beer can get infected at packaging.  Flash pasteurization has the same limitation as sterile filtration in that pristine beer can get infected immediately after it exits either the sterile filter or flash pasteurizer, so greater care is required, and more hygienic engineering design integrated. A ‘sterile fill-capable’ filler can cost at least $1.5 million, yet a “normal” beer filler (not aseptically-certified) at the same throughput can cost as little as $225,000.  

Since the USA has no larger-scale packaging machinery fabricators, the European standard testing A-3 is the baseline aseptic-capability certification testing. The growth of canned beer has led to a variety of small, linear canning systems which are clearly microbiological traps for beer being packaged. 

But when a company invests in a tunnel pasteurizer designed and engineered to suit the purpose by PRO Engineering, the process is on the packaged beer inside the can or bottle. 

Many craft beers cannot be sterile filtered, and those that are may experience some degree of flavor scalping and stripping as the beer is pushed through 0.22 micron to 0.45 micron polymeric or ceramic filtration media. 

It is true that pasteurization at least temporarily changes beer flavor, but in work I’ve done, the best flavor panel in the world could not discern Control vs Pasteurized after 3-7 days had passed when controls and tests were stored at ambient temperature (for mainstream-style lager beers). When you briefly heat beer, you increase the rate of oxidation during that period, but after 3-7 days, the level of oxidation effects are the same in unpasteurized beer (2). 

Is it true that many, many small breweries have no sterile filtration nor pasteurization of any kind? Of course that is true. And some of these beers travel quite far before they are consumed, often having long storage times, too. Loads of people are happy to drive without seat belts while also texting on their mobile phones. Despite understanding the risks, loads of people enjoy smoking cigarettes and some people happily let their children enjoy swimming in the pool unsupervised.  

A pasteurizer represents an investment and a commitment to sustained quality and security as much as putting on that seatbelt and choosing to not text while driving. It’s true that a number of beer aficionados look down on the process, express that only mega-breweries use it, that’s it’s wrong for craft beers. And there certainly are brewers who came into professional brewing from backgrounds which had no tunnel pasteurizers in their past, and use their platforms as brewers in craft breweries to reinforce the opinions that pasteurized beer has had some of it specialness removed.  

Every Master Brewer I know who pasteurizes beer sleeps better because it is inevitable that sometimes something will slip through, from a slight tear on a filter pad, for example, or a chance passage through an imperfectly cleaned and sanitized hose or coupling or union. And if not denatured, it could change flavor in the package for worse. 

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We all know how draught beer can sometimes disappoint us, and we know that if lines aren’t cleaned correctly and with the right frequency, then the beer itself changes flavor. That is a concern that extends to flash-pasteurized or sterile-filtered beer, also: how clean is everything touching the beer after it has gone through the particular process? 

In the engineered PRO pasteurizer serving for beer pasteurization, the sequence consists of a heat-up phase producing a uniform rise in temperature, a phase of heating at a temperature level and a cooling down phase, the heating and cooling of the container holding the liquid achieved by a spray of water from non-clogging spray heads whose temperature is a function of the zone in question. The conditions under which the pasteurization must take place are a function of the product to be treated, the geographical distribution point, the pollution of the base product and requirements of the law.  

For a given beer, the operation of pasteurization should require, for example: 

–Exceeding a temperature threshold for a definite time, which can be very short, 

–Standing at a temperature for a minimum time, 

–The acquisition by the product of a certain number of “pasteurization units” or PU’s, 

Remember that a PU is defined as the effect of pasteurization obtained, for example, in beer by holding for one minute at 60° C. (140° F). The pasteurization effect is by definition the biological destruction produced by holding at a predetermined temperature, which is a function of the product, for a certain time. To this end, in various zones of a PRO pasteurization tunnel, various temperatures are adjusted with which the temperature of the products can be slowly increased and possibly subsequently slowly reduced again. 

A beer with low counts of anaerobes and aerobes may exit a pasteurizer with zero counts with 8 PU, but another batch with higher counts may need 12 or 15 PU. Beers shipping internationally are best given higher pasteurization, ie 20 PU. The team at PRO can discuss how to evaluate pasteurization targets, PRO also offers innovative batch pasteurizers models for smaller runs and research operation to validate PU targets, 

Authored by Jaime Jurado

Past President-MBAA(Master Brewers Association of the Americas)
https://www.linkedin.com/in/jaimejurado/
https://independent.academia.edu/JaimeJurado

Article References:
https://doi.org/10.1111/j.1745-4549.1991.tb00151.x
https://doi.org/10.1111/j.1365-2621.1994.tb02061.x 

Sponsored by Ed Michalski, CEO PRO Engineering and Manufacturing, Inc

PRO and Manufacturing, Inc has been providing equipment and engineering services to the beverage industry for 42 years. Contact Ed Michalski, CEO at: (414) 362-1500, [email protected]

ABOUT US:
PRO Engineering and Manufacturing was established in 1977 by Ed and Dave Michalski as a steel fabrication shop. For more than 40 years, PRO Engineering and Manufacturing, Inc. has been delivering solutions for beverage product shelf stability and consumption safety. As leading innovators in post-fill pasteurization, our skilled team offers the best in high-quality pasteurization equipment.

CONTACT US:
Phone: 414-362-1500 | Email: [email protected]

ABOUT US

PRO Engineering/Manufacturing, Inc. was established in 1977 by Ed and Dave Michalski as a steel fabrication shop. From this modest beginning, complete machine fabrication capabilities were quickly added followed by the installation of our own in-house engineering and design group.

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