Use of Charcoal Flue Gases in the Preservation of Beef for Prolonged Storage
Wanja, Njeru Catherine
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Flesh from animals is one of the nutritious food items. Due to this high food value, it attracts bacteria, yeasts, molds and other lower life forms that infest on it and hence undergoes natural decay process fast. Poor handling practices by small scale enterprise in the beef industry contribute to fifty percent loss, excluding post slaughter losses by livestock. The post slaughter losses are due to inadequate beef preservation infrastructure available to farmers. This affects not only food safety and security leaving farmers economically vulnerable and malnourished but results in a lot of waste. Therefore, there is need to develop accessible preservation methods that are supported by available infrastructure to farmers in order to curb beef losses. Beef spoilage occurs due to lipid oxidation, microbial spoilage and autolytic enzymatic oxidation. This study used charcoal flue gases sourced from combustion of charcoal briquettes in prolonging beef shelf life. The charcoal flue gases protected the functional groups in beef that hoist group of pathogens. Gas composition in a reactor chamber was monitored using a multiple digital gas meter. Fresh beef samples were purchased from local abattoirs and exposed to flue gases and stored for further investigation. Beef sizes of 1.0, 1.5 and 2.0 cm thickness, fixed length and fixed width were used in this study. The treatment time, temperature, pH, % moisture, beef size, and beef load were studied. Data was analysed using analysis of variance and regression. The 1.0 cm thickness, 5.0 cm width and 10.0 cm length beef sizes of 5.00kgs mass took the shortest time in the treatment chamber of 10 hours while mass above 6.00kgs different thickness 5.0 cm width and 10.0 cm length took 15 hours in the treatment. The optimum treatment time was between 10 to 15 hours depending on beef load mass. The temperature range of 25.0 to 37.0 ◦C was optimum for different beef sizes. The pH of fresh beef was 5.5 and reduced to 4.5 after treatment for day 30. The beef percentage moisture was 23.41 % on day one, 67.72 % on day 3 for fresh beef and remained constant at 44.76 % for the treated beef. The reaction of the carbon monoxide and carbon dioxide with beef functional groups was studied using color determination and fourier transform infrared spectroscopy. The displacement of the band at 1587.44 cm-1 after treatment and appearance of a band at 1749.17 cm-1 is due to the angular deformation of the N-H (amine group) giving rise to the inclusion of a carbonyl functional group. The band at 2100 and 2290 cm-1 corresponded to carbon monoxide and carbon dioxide absorbed in the beef. The colour lightness (L*) and redness (a*) values were L* 44 ±0.1 and a* 9±0.1 values for fresh beef, after treatment L* 30 ±0.1 and a* 4.5 ±0.1 indicating a strong bond of carboxy-myoglobin and on day 35 the L* 23±0.1 and a* 1.5 ±0.1 indicated onset of beef spoilage. The mean total microbial counts of fresh beef, after treatment and onset spoilage were significantly different (p<0.05) 4.16±4.20, 2.16±2.19 and 5.16±5.20 log CFU/cm2 respectively. The results from this study, was not more than 6.00 log CFU/cm2 approved safe microbial standards of beef for consumption by FAO. This study presents an accessible method for prolonging beef shelf life for 30 days with available infrastructure. The study recommends use of charcoal flue gases in prolonging shelf life of beef and other meat types.