April 2021

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Monthly Archives: April 2021

A Basic Guide to Purchasing and Using Tunnel Pasteurizers

By Edward A. Michalski

CEO

PRO Engineering/Manufacturing, Inc.

Tunnel pasteurizers are efficient and effective machines that are available in numerous sizes. The food and beverage industries use them to kill microbes, stop fermentation and in general, provide shelf stability.

These machines are subject to significant heat variations, caustic cleaning chemicals, steam, water, huge mechanical stresses and in many applications, broken bottles.

PRO Engineering/Manufacturing, Inc. has been maintaining, repairing and re-engineering tunnel pasteurizers for over four decades. PRO designs and builds our own tunnel pasteurizers and refurbishes competitor’s machines.

There are different types of tunnel pasteurizers classified by the mechanism that moves the pasteurized product through the tunnel.

Walking Beam

This is an older configuration that employs alternating strips, picking and stepping product forward. Most of these machines are being re-engineered into belt pasteurizers.

Belt

This is a newer design that uses stainless steel or plastic mats/belts. The Mid 90’S transition away from walking beam saw the advent of perforated plastic belts, wire mesh belts and hybrid versions. (plastic and metal combinations)

Carrier

These are formed carrier channels that are mounted to roller chains on each side. The channels support the product and transfers it through the tunnel.

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SlimLine Tunnel Pasteurizer
(Small Tunnel Pasteurizer)

Next, let’s look at the areas/sections of a tunnel pasteurizer.

Infeed

This is the area at the entrance to the machine. It can be problematic if the infeed conveyor does not hand off the bottles/cans to the mat/belt effectively.

Sump

The area under the belt that catches the water after it has flowed over the cans/bottles/packages that contain the product being pasteurized. The quality of the bottles can be a factor in the amount of bottle breakage. If breakage occurs, the material can be captured in the sump or continue to move out and drop off from the discharge conveyor.

Watertight Access Ports

These openings are watertight ports positioned on the side of the tunnel to give maintenance workers access to the belt and/or the sump for cleaning or service.

Zones

The tunnel is divided into multiple zones from the front to the back of the machine. The zones have spray nozzles or drip pans inside them, at the top of each zone. The various zones spray water at different temperatures to warm and cool the product being pasteurized.

Pasteurization Units

Although not a part of the pasteurizer, pasteurization units, are an integral part of operating a pasteurizer correctly. Abbreviated as PUs, pasteurization units are a measure of the amount of time and temperature a food or beverage has been subjected to, in order to kill off microbes and deactivate yeast cells. The pasteurization units are equal to 1 PU when the product is exposed to 60°C (140°F) for one minute Depending on the type of food or beverage, the PUs required for appropriate pasteurization varies.

Pasteurization Unit Monitor

A pasteurization unit monitor performs the function of monitoring the PUs (pasteurization units) that the beverage or food has been subjected to during its ride through the pasteurizer. The monitor is a system that consists of hardware and software. The hardware travels on the belt with the product being pasteurized. After the trip is finished, the hardware downloads the measurements of time and temperature to a laptop computer and the PUs are calculated.

Controls

PLC-based controls that use an HMI (Human Machine Interface) are standard. The PLC will have numerous programs available to be loaded in it that control the water sprays inside the tunnel. Time and temperature are varied depending on the product being pasteurized.

Discharge Area

The discharge is at the back of the tunnel pasteurizer. At this point, the bottles/cans are transferred from the internal mat/belt to the external conveyor. A good hand-off is required.

Tunnel_Series_5_PRO Engineering Manufacturing Inc

PRO/Line Series 5 Tunnel Pasteurizer
(Medium Sized Tunnel Pasteurizer)

Heat Recovery System

The main component of the heat recovery system is the heat exchanger. The heat recovery system takes heat from containers (bottles and cans are most common) at the discharge end of the tunnel by circulating water used to heat the containers and sending the hot water to the infeed end of the machine to start to heat the containers at the beginning of the pasteurizing process.

There are various types and configurations of heat exchangers:

Plate Configuration Heat Exchangers

Advantages:
- Single, larger plate version can supply all the needed energy
Disadvantages:
- Requires shielding from possible steam leakage
- More expensive to clean and maintain

Tube and Bundle Heat Exchangers

Advantages:
- Very efficient heat transfer
- Easy cleaning by CIP
Disadvantages:
- Multiple units are required

Heat Sources

Boilers

Low-Pressure Steam

- Advantages:
  - This option doesn’t a need licensed boiler operator/Less cost
- Disadvantages:
  - Much slower heat transfer occurs

High-Pressure Steam

- Advantages:
  - Faster heat transfer
- Disadvantages:
  - Need licensed boiler operator
  - Regulated by local authorities

Super-heated Hot Water

- Advantages:
  - More efficient heat delivery than low steam
  - Doesn’t need as many components as steam to return condensate to boiler.
- Disadvantages:
  - Regulated by local authorities

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PRO/Line Series 14
(Large Tunnel Pasteurizer)

Spray Nozzles

Nozzle sizes

Large orifice (reduced clogging) (more expensive)
- Large Orifice Nozzle Versions
  - Low flow, large droplets
  - High flow, large droplets
Small orifice (less expensive) (prone to clogging)
- Small Orifice Nozzle Versions
  - Low flow, high velocity

Spray Pans

Easy to clean
Prone to clogging
Version
- High flow, low velocity

Belts/Mats

Plastic
- (easy to install) (light weight) (lower initial cost, higher operating cost) (prone to chemical attack) (lower maximum temperature) (easier to break) (require frequent maintenance) (shorter life cycle) (susceptible to UV attack)
Stainless Steel
- (Higher initial cost) (longer life cycle) (greater chemical resistance) (broader temperature range) (reduced maintenance) (lower operational cost)

Guides

Commercially Available Product Guides
- (Readily obtainable) (market priced)
- (easier installation) (good for bottles and cans)
Stainless Steel Guide Plates
- (Good for bottle lines) (poor for cans)
- (low maintenance) (long life)

Fabricated Plastic Side Guides

Various plastics are available
- Various levels of chemical resistance are offered
- More chemical resistance equals less physical flexibility
- Susceptible to UV attack
- Flexible plastics-good for can lines, fair for bottle lines
- Higher temperature rigid plastics available

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Pasteurization Unit (PU) Monitor Hardware and Software

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SUMMARY

This is a basic guide that you can use when considering the purchase or the operation of a tunnel pasteurizer. PRO Engineering/Manufacturing has been refurbishing, designing and building tunnel pasteurizers for over 40 years. We offer the widest variety of small, medium and large sized tunnel pasteurizers along with batch pasteurizers. Contact us to learn more!

For more information on tunnel and batch pasteurization contact PRO Engineering/Manufacturing, Inc. at [email protected] or call (414) 362-1500 and ask for Ed Michalski, CEO. 

Edward A. Michalski Bio 

Ed Michalski started his career in the beverage industry by designing stainless steel, higher flow, spray headers for Pabst Brewing. Along with the header design he also developed a process to produce the new headers.  

Ed, along with his brother David, formed PRO Engineering/Manufacturing, Inc.

Based on what they learned by re-designing and refurbishing other manufacturers’ pasteurizers, Ed and PRO started to offer the pasteurizer marketplace superior new pasteurizers. 

PRO Engineering/Manufacturing has been designing and manufacturing great pasteurizers for over four decades.

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]

Previous Article: BATCH AND TUNNEL PASTEURIZATION FOR CIDER/HARD CIDER PRODUCTION

Tunnel and Batch Pasteurization versus adding Artificial Preservatives to Food and Beverages

By Edward A. Michalski

CEO

PRO Engineering/Manufacturing, Inc.

According to the International Food Information Council, in 2020 nearly half of consumers look at the ingredients label when making buying decisions, and 25% try to avoid certain ingredients, including artificial food preservatives. These numbers indicate the growing “clean label movement”, which is the biggest trend of the decade in packaged foods.

As consumers’ decisions change based on their food’s perceived healthiness, the clean label trend drives the food industry to examine production processes and ingredients. As mentioned in the Harvard Business Review, even the big, mainstream food companies are moving towards more natural methods and ingredients. During the Sustainable Brands Metrics Conference, business leaders declared that this generation of parents, workers, and consumers –Millennials– are twice as likely to check product packaging and labels; hence, minimally processed and socially responsible ingredients are becoming a non-negotiable essential for food labels. Lastly, the Food Technology Magazine reports that the global 2n 2020 bel”ucers are enacting “eclean label food sales in 2020 are worth around $180 billion compared to $ 165 billion in 2015.

The clean label trend is challenging the food and beverage makers to provide products with fewer ingredients and to use alternative processes that exclude artificial additives and preservatives. Interestingly, specific production methods are perceived as more “natural” than others, while certain food components are perceived as “unhealthy,” such as artificial beverage preservatives. Although preservatives prolong the shelf life of food and beverages, these additives –nitrites, nitrates, and benzoates (parabens)– can be toxic, and some have even life-threatening effects.

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Research has shown that artificial preservatives such as sodium benzoate, potassium benzoate, velcorin, and EDTA can cause headaches, diarrhea, allergies, asthma, neurological disorders, and cancer.

Further, some antioxidants like propyl gallate, butylated hydroxytoluene (BHT) and butylated hydroxylanisole (BHA) slow or stop the breakdown of fats and oils. At the same time, some preservatives block the enzymatic processes.

Therefore, avoidance of artificial ingredients has caused manufacturers to struggle maintain a balance among more natural processes, keeping food safe, and maintenance of profits. One alternative to solve this dilemma is using tunnel and batch pasteurization to help achieve a “clean label” on their products.

Pasteurization is a physical preservation technique where food and beverages are heated up to specific temperatures for specific times to destroy spoilage-causing microorganisms. This heat treatment kills most pathogenic bacteria and yeast. There are several options of pasteurizers: high-temperature short time (HTST), also called flash pasteurization; ultra-high temperature (UHT); and low-temperature long time (LTLT) including batch, and tunnel pasteurizers.

However, flash pasteurization requires supervision to prevent overheating. Certain physical, biological, and chemical changes can occur in food and beverages due to the excess of heat; for example, the heat may damage vitamins and minerals. For this reason, batch and tunnel pasteurization are recommended when looking to provide a “clean label” product to the marketplace.

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Tunnel and batch pasteurizers often operate by heating the product to approximately 60 °C (140 °F) for a pre-determined time. Manufacturers use Pasteurization Units (PU) along with time-temperature magnitudes to monitor the process and the “lethal effect” of the heat on the microorganisms. The pasteurization units are equal to 1 PU when the product is exposed to 60°C (140°F) for one minute. Depending on the type of food or beverage, the PU required for appropriate pasteurization varies. Beverages such as beer, fruit juices, cider, cold coffee, and milk all need different PUs, and the same is true with foodstuffs.

PRO Engineering Batch Pasteurizer-Spray Version

Tunnel and batch pasteurization receive the beverage or food products already packaged. In tunnel pasteurization the packages sit on a traveling belt and are led to progressively hotter zones, holding/pasteurization zones, and colder zones until reaching the desired “out” temperature, for example, 20°C (68°F). The process uses water sprayed at different temperatures on the packages. The container is heated by conduction and the beverage is heated by convection. Batch pasteurization is similar to tunnel pasteurization but does not move the packages through various zone on a moving conveyor belt. Batch pasteurizers are classified as either “tank” or “spray” batch pasteurizers. Tank versions lower the product into a tank of heated water and spray pasteurizers spray heated water on the containers inside an enclosure

As food retailers, manufacturers, and producers are enacting clean label guidelines, much effort has been put forth to optimize the processes of beverages, ready-to-eat meat, poultry, and other products. Fuhrman et al. (2018) recognized that post-packaging tunnel pasteurization offers multiple benefits for producers in the meat and poultry industry.

Tunnel pasteurizers eliminate important pathogens from the surface of ready-to-eat products achieving safety without adding nitrites or other antimicrobial agents; therefore, resulting in a cleaner labeled product. Similar conclusions were published by Higgins et al. (2014) highlighting the broad acceptance that pasteurization has gained in the U.S. and Canada.

Consumers looking for healthy, natural, and simple foods are actively avoiding products made with chemical ingredients. As this “clean label movement” spreads, food and beverage manufacturers have to keep pace by removing artificial ingredients from their products. One alternative to accomplishing this is through tunnel or batch pasteurization.

For more information on tunnel and batch pasteurization contact PRO Engineering/Manufacturing, Inc. at [email protected] or call (414) 362-1500 and ask for Ed Michalski, CEO.

Edward A. Michalski Bio

Ed Michalski started his career in the beverage industry by designing stainless steel, higher flow, spray headers for Pabst Brewing. Along with the header design he also developed a process to produce the new headers. 

Ed, along with his brother David, formed PRO Engineering/Manufacturing, Inc..