9th September 2010 17:02
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Trouble Shooting in Bakery Leads to Infrared Surface Pasteurization
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Problem Statement
Mould growth shortened the shelf-life of the SME company’s sponge cake products from 12 to 3 weeks. The company lost 150 000 Euros during 2001 and their position on the Norwegian market. |
Improvement Approach
Infrared heating could provide surface pasteurization at relatively low cost with only small changes in the production line. |
Benefits
Six months after the project started the equipment was in place and the production of sponge cake was back to normal. The pay-off on investment was less than three months. |
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Company Contact Information
SIK The Swedish Institute for Food and Biotechnolo
Emma Holtz, SIK, Box 5401, SE-402 29 Göteborg, SWEDEN
Tel.
+46-31-335 56 00, Fax. +46-31-83 37 82
E-mail
eh@sik.se
www.sik.se
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Surface pasteurization of sponge cake using infrared heating.
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The Swedish SME company produces different kinds of sponge cake products. Their turnover is 6 000 000 Euros and 25% of the company’s produce is exported.
In the beginning of 2001 the company experienced problems with mould growth. Despite many years of problem free production and well established hygiene routines the problems grew.
The typical shelf-life of sponge cake is 12 weeks. In June 2001 the shelf-life was barely three weeks and of course the company had customer complaints every day, especially on the exported products.
During 2001 the company lost 150 000 Euros of its’ profits. In addition the company lost its’ position on the Norwegian market.
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A fast response was crucial to the customer. The solution would have to be one that could quickly be adopted. It should also be a solution that the customer could bear economically.
Use of the antifungal additive propylene glycol in Swedish sponge cake products was forbidden in 1997. Therefore, the solution would have to be a technical one. It was also very important that the customer could be confident that the solution would be effective.
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The crucial step when baking is very often the cooling zone after the oven. A baked product is practically sterile as it leaves the bake oven, but before it is packed it is usually allowed to cool to a temperature of about 30°C. During the cooling time the product is susceptible to air born contamination.
In this case the bakery line already existed, which limited the possible methods of preventing contamination. Ensuring totally clean air or packaging without prior cooling would involve too large changes in the production. Therefore, it was decided that the products would be surface pasteurized before packaging.
Infrared heating was the choice of technology. The equipment is robust and easy to handle and the energy consumption is small compared to conventional heating as only the product surface is heated, not the surrounding air. The equipment is also compact and requires relatively small space.
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Tests were performed in pilot scale to define necessary process parameters. Parameters such as treatment time, surface temperature and necessary power distribution were defined. Also if short wave or medium wave infrared heating should be used. Shelf-life studies were also performed by inoculating products with mould, subjecting the inoculated products to a given process and evaluating the product for mould during at least 12 weeks.
As time was short discussions were held with the equipment supplier in parallel with the trials. This shortened the delivery time of the equipment. The customer also felt a greater support when ordering the, for them, totally new equipment.
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After installation of the new equipment there has been no mould contamination of the products. The improvement has been very noticeable to the company’s customers.
The pay-back time was less than three months calculated on the loss of profit.
The installation has not affected the capacity of the baking line and is easy to handle, maintain and clean, i.e. the changes for production and maintenance personnel are small.
The company experienced that it was an additional support to involve SIK also in the discussions with the equipment supplier.
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