Postharvest losses in oyster mushroom (agaricus ostreatus) produced in the Ho Municipality of the Volta Region of Ghana

The study was carried out in the Ho Municipality of the Volta Region of Ghana to assess postharvest losses during oyster mushroom production in the Municipality. Simple random sampling was used to select the producers, marketers and consumers for the interview. Data gathered was analyzed using Statistical Package for Social Science. Linear regression analysis (version 9.0) was used in estimating the major contributing factors to postharvest losses in oyster mushroom production at the producers, marketers and consumers levels. In a laboratory work, one hundred and eighty (180) pieces of freshly harvested mushrooms uniform in size and shape were used. A 3x2x2 factorial experiment established in a Completely Randomized Design (CRD) and treatments were replicated three times. The factors consisted of three different packaging periods (0 hour, 12 hours and 24 hours), two different packaging materials (perforated polythene bags and opened transparent plastic bowls) and two storage environments (refrigerator and room temperature). Each sample was weighed daily with electronic weighing balance, in grams, to determine weight loss. Data gathered were analyzed using GraphPad Prism (version 4.0). Post-hoc Tukey test was conducted on all computed weight losses for all time-dependent treatments to identify any true or significant interactions and possible significant differences between treatments. The survey revealed that majority (40%) of the producers had between 1001-1500 oyster mushrooms composted bags in their production houses and majority (43.3%) of them produced between 41-50kg mushrooms per week. Majority (42.9%) of the marketers sold between 41-45kg mushrooms per week while majority (44.3%) of the consumers consumed about 3-4kg mushroom per week. The level of postharvest losses of oyster mushroom from producers, markers and consumers fell within 40-60% range. The regression analysis revealed that time of harvesting of the mushrooms, number of years of experience of marketing the mushrooms and storage methods were the major contributing factors or causes to postharvest losses of oyster mushrooms in the Ho Municipality. Other factors included high moisture content of mushrooms, postharvest changes, poor storage technology, exposure to heat, inadequate storage facilities, texture changes, brown discolouration and dehydration. During the storage period, weight loss and shelf life were observed. The laboratory studies revealed that oyster mushroom samples that were kept at room temperature lost more of their weights than replicates that had been stored in a refrigerator at 2-30C with 8-10% relative humidity. Oyster mushroom samples that had been packaged into perforated polythene bags and stored in a refrigerator at 2-30C had longer shelf-lives than oyster mushroom samples kept in room (average temperature 300C with 61% relative humidity). The grey colour of the oyster mushrooms changed to orange colour and felt soft in texture for mushrooms packaged into perforated polythene bags and but had firm texture for samples packaged into opened transparent plastic bowls and stored in a refrigerator at 2-30C (8- 9 days). However, samples that were packaged into perforated polythene bags and opened transparent plastic bowls but stored at an average room temperature of 300C showed orange colour with dark spots and felt soft in texture 2-5days respectively. Packaging into perforated polythene bags immediately after harvest and stored in a refrigerator at 2-30C with 8-10% relative humidity had longer shelf life of 8 days. Samples packaged 12 hours after harvest into perforated polythene bags and kept at room temperature of 300C with 61% relative humidity had 3 days shelf life while samples packaged 24 hours after harvest into perforated polythene bags and kept at room temperature had 2 days shelf life. It is recommended that harvesting of mushroom should be done in the morning, packaged immediately after harvesting and stored under cool conditions.

Source: KNUST