Flame Pasteurizing ‘Sizzles’

9. 60 in flame grill

A breakout solution for pathogen control increases shelf life and productivity on RTE meat and onions.

To achieve the needed food safety and cooking efficiencies, many meat and poultry items such as hams, turkeys and chickens are today cooked in a pouch or bag, using water or steam, and then chilled. However, when processors need to add color, texture or flavorful seasonings to these items, in order to satisfy consumers’ taste preferences, additional post processing is required. The question is, what is the best way to attain those desired effects and also maintain extended shelf life?

The answer for many processors today is a breakout technology that can roast, flavor, sear and color meat and poultry while also providing the needed surface pasteurization to significantly extend shelf life – the “tunnel of fire” pasteurizing and flash roasting system.

Using the flame tunnel processors simply take the cooked and chilled whole poultry or meat products from the chiller and place them on a belt that moves the products through an enclosed flame that will color, sear and surface-pasteurize the products so that they are ready for immediate packaging. Because of the speed of the process – normally 30 to 60 seconds – complete surface pasteurizing and searing is achieved, yield loss is minimal and a long shelf life is ensured.

Flame tunnels such as Unitherm Food Systems’ Tunnel of Fire also include a dispensing unit that sprays browning and flavoring agents such as liquid smoke or other seasonings onto products as they enter the tunnel. This allows the color, texture and flavor of delectable products such as barbeque rotisserie-style chickens and honey-roast hams to be easily and consistently controlled.

Using this flash roasting and pasteurizing process, finished products maintain their cool core temperatures, and can be immediately packaged for distribution. This eliminates food safety problems that can occur when products are cooled in the open air prior to packaging, which exposes them to cross contamination that can limit shelf life to a few days rather than weeks.

Shelf life of 40+ days

Roasted chicken, a perennial favorite all over the world, provides a good example of how the right flame roasting and pasteurizing process and equipment can meet customers’ taste preferences while also extending shelf life.

Comercializadora Andina SA (Comansa) of Santiago, Chile produces a line of foods sold to supermarkets, including chicken, beef and other meats, plus a ready meal line that is mainly provided for the Chilean School Feeding Program. 

One of the company’s primary products is roasted chicken, which is sold to supermarkets throughout the country at the rate of about 80,000 units per month. Eduardo Carvajal, Comansa Operations Manager, says that providing these chickens in a rotisserie style and an assortment of seasonings has enhanced sales and also offers other benefits. 

“We cook the chicken in bags in a steam tank for about three hours, then chill it in the same unit,” he explains. “Afterwards we put the chicken through the Unitherm Tunnel of Fire to keep surface pasteurizing, and get the color and develop the seasonings. This is all done in just 30 to 35 seconds.”

Carvajal says that using the flame tunnel provides important benefits besides the assurance that each chicken is exposed to the air for only seconds before it is surface pasteurized and put in retain bags immediately afterwards, ensuring that it will remain safe.

“The coloring process of the flame tunnel is very important because our customers prefer that finish rather than a plain white color,” he explains. “Also, the same equipment enables us to provide a variety of seasonings, including spicy, barbeque, butter and sweet flavors.”

One of the most important benefits of the flame pasteurizing process is the extended product shelf life. While many roasted chickens have a typical shelf life of about three days, Carvajal’s is considerably longer.

“After we ship the chicken, we are certain of a shelf life of 42 days,” Carvajal says, “and that is an important reflection of our high standards.”

Speeding throughput

Luka Meats (Luka Vleeswarenfabriek NV), Vilvoorde, Belgium, has offered an elegant variety of cooked hams, including smoked, roasted, and extra lean hams as well as Strasbourg meat loaves since 1970.

Until recently, the hams and Strasbourg loaves were pasteurized, browned and seared by hand, using a hand-held torch, but handling 1,200 hams and 300-400 loafs per week was just too time consuming.

“We used to spend an average of two hours a day finishing these products by hand,” says Thomas Leemans, Luka Meats founder and owner.

Recently, Luka Meats automated its pasteurizing process with a Unitherm Tunnel of Fire flash roasting system.

“This new equipment makes quite a difference in productivity,” Leemans explains. “We now save approximately 60 percent of the time it used to require to brand our products by hand, as well as considerable labor.”

9. flame peeling

Peeling the onion

Flame pasteurization provides another set of benefits when it comes to ensuring the processing efficiency and food safety of vegetables.

“There has been a lot of concern in recent years about produce safety when it comes to field-grown vegetables,” says Peter Muriana, Ph.D., a food microbiologist at Oklahoma State University in Stillwater, OK. “But the presence of these pathogens on vegetables and produce is not surprising it’s really not news because many of the pathogens that cause outbreaks, such as Salmonella and Listeria are enteric pathogens, which can colonize in the intestinal tracts of domestic or wild animals, birds, amphibians, and reptiles, and are readily shed in their feces in the fields where the vegetables grow, or find their way into water retention ponds used for irrigation. So, the exposure of plant life to these pathogens is quite common and not an unexpected occurrence.”

Dr. Muriana was recently involved in a project to test for surface pasteurization of whole onions to eliminate potential pathogen contamination on post-harvest onions.

“Onions are a highly popular ingredient in many processed foods, and are therefore deserve thorough consideration when it comes to food safety,” says Adam Cowherd, Sales Manager of food processing equipment manufacturer Unitherm Food Systems (Bristow, OK).

Because the potential for pathogen contamination of onions and other vegetables occurs on the outer surfaces, the OSU study concentrated on the flame pasteurization of onion skins via Unitherm’s Flame Grill, a small-footprint system that individually quick flames (“IQF”) products such as vegetables and proteins.

The OSU study concluded that, using the flame grill, nearly a 5-log reduction of indigenous bacterial contamination was obtained, as well as a 4-log reduction of yeast and mold (below level of detection after processing), and a 6-log reduction of inoculated Listeria innocua.

Use of the flame grill for pasteurization also minimizes yield loss of onions and other vegetables. Cowherd says that field tests showed that conventional mechanical peeling of whole onions resulted in an average of about 30 percent loss of the onion, whereas those processed on the flame grill lost an average of only three percent.

“The flame process burns off only the paper-like layers on the surface of the onions,” he explains, “which makes the removal of only the skin portion quite easy compared with the traditional mechanical peeling method, which causes quite a bit of yield loss – and does not totally eliminate the potential for pathogen cross contamination.”

Flame grilling is also highly useful in the pasteurization and peeling of other vegetables, such as capsicum peppers. Cowherd says that, in many instances, yields are significantly improved, and energy efficiencies are increased over mechanical methods.

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