Vol. 1, Issue 13, Part B (2015)

Abstract
Canned products like tomato paste on the Ghanaian market are sometimes sold on open market. This practice leads to accelerated deterioration of the product and leaching of metallic constituent of the can into the product. Levels of tin and iron were analyzed in eight different brands of canned tomato paste namely A5, A3, A6, A1, A7, A8, A4 and A2 stored under different experimental conditions. Samples were subjected to in room (28 °C, relative humidity of 70-78), fridge (≤4 °C) and under simulated tropical condition of ambient temperature at 32 °C and relative humidity at 85%. The initial concentrations of tin in the different brands range from 0.0519 mg/kg to 2.7029 mg/kg. The Tin content for the initial analysis were found to be less than the maximum acceptable limit of 250 mg/kg. The tin content in all samples after test in varying conditions remain within the acceptable limits though an increase of up to 4.3688 mg/kg was observed in A3 products. The iron content in the different brands range from 25.1300 mg/kg - 86.7373 mg/kg. All the canned tomato paste contains the mineral iron higher above the acceptable limit of 15 mg/Kg. A1 recorded the highest iron concentration of 97.9756 mg/Kg and the least in Gina’s with concentration 26.3123 mg/Kg in samples stored in fridge at week 6. A3 tomato paste recorded the highest concentration of 143.8379 mg/Kg and the least in Gina’s tomato paste with content 39.9452 mg/Kg at 6th week of storage at room temperature. A1 recorded the highest concentration of 204.8071 mg/Kg and the least in A4 with concentration 47.3405 mg/Kg in samples stored under Simulated Tropical Temperature and Humidity for 6 weeks. The rate of leaching of metallic constituents from the metallic container into the paste of tomato increased with an increasing temperature. 18.1380 mgKg-1week-1 was the highest rate of iron migration recorded with the least <0.0001 mgKg-1week-1 for Tin. The exposure of canned tomato paste on the open market could render the product unwholesome for consumption by shortening its shelf life as observed for products subjected to Simulated Tropical Temperature and Humidity. The tin and iron content in each product remained virtually stable during storage under refrigeration conditions but varied under room and Simulated Tropical conditions with significant difference in the tin and iron content at 95% confidence interval.