Improving hot air processing of fish using the chorkor smoker: development of an improved smoking oven "Afrismo-150"

Abstract

The need for an efficient, cost effective smoking oven that eliminates the interchanging of tray positions, reduces heat loss and makes fish smoking less laborious as well as addresses the reduction elimination of tar deposits usually associated with fish processed by the chorkor smoker has resulted in the design and construction of an improved smoking oven at the Food Research Institute (FRI) of the Council for Scientific and Industrial Research (CSIR). The oven, AgSSIP/FRI Smoking Oven (AFRISMO) model AFRISMO-150 was devloped under the Agro-Processing Programme of the Agricultural Services Subsector Investment Project (AgSSIP). AFRISMO-150 is an an improvement to the popular chorkor smoker. It is an enclosed rectangular shaped structure consisting of three basic components two firing sections, cooking chamber and a chimney. It can be fired by firewood only or Liquified Petroleum Gas (LPG) only or a combination of LPG and firewood. This report covers the design, construction and test run of the AFRISMO-150 using firewood only for the smoking of Mackerel fish. Temperature distibution tests conducted during smoking within the oven recorded highest temperature difference of 29°C at 90th minute and maximum operating temperature of 195°C at llOth minute of operation as presented in Table 1 and Figure 5. The test run also established a smoking capacity of 150kg of fresh fish per batch of 3 hours, fuel consumptions of 39.5 kg of firewood (i.e.unit fuel consumption rate of 0.33 kg of firewood per kg of smoked fish). Yield of 80.6% and moisture loss of 19.4% were also recorded as presented in Table 2. Microbiological analyses carried out on the smoked fish showed absence of faecal coliforms, spoilage and food poisoning microorganisms proving that the smoked fish is safe for human consumption and would not pose any health hazard when consumed. The total cost of construction of the AFRISMO-150 is ¢2.500.000 ($280)