Fabrication And Performance Evaluation Of Cold Storage System

2.6    Hygiene Procedure for Cold Storage Structures
In order to prevent pathogen built-up within the facility, strict hygiene measures are pivotal.  All hygiene measures have to take necessary safety measure for staff into consideration
i.    Clean thoroughly at the end of each season:  what walls and floor with sanitizers such as hypochlorite solution (FAO 2009)
ii.    Use of ozone generators to prevent molds and fungi (FAO 2004)
iii.    Regular ventilation to avoid build-up of ethylene, carbon dioxide and odors (FAO 2009).
iv.    Many researchers have worked on cold room storage structure.  Among which are as listed below:
v.    Isenberg (2004), reported on storage guideline for fruits and vegetables that modern basement with furnaces are generally at lease 50 –500fand dry. While this is appropriate for some types of food storage, in order to achieve the cool, moist conditions necessary for most fruits and vegetables it may be necessary to construct a separate room.  This separate storage areas should be located in the coldest part of the basement, away from the furnace.  The north and the west sides of the house are preferred. Avoid heat dust and hot water pipes that generate heat the room should have an outside window for ventilation.
vi.    Kader (2005), reported on temperature control-cold storage for fruits and vegetables.  Fresh food products are characterized by their perishability, and levels of vulnerability to pest and spoilage; however, in general the control of temperature and relative humidity and the prevention of damage can increase shelf life, especially of fresh fruits and vegetables, tremendously. Biological deterioration, caused by respiration rate, ethylene production mechanical injuries, water stress, physiological disorders and pathological breakdown, leads to decay, loss in nutritive value and changes in colour, texture and flavor. Factors influencing the rate of deterioration are temperature, the level of relative humidity, air velocity, and atmospheric composition, i.e. concentration of oxygen, carbon dioxide and ethylene, as well as sanitation.
vii.    FAO (2004) reported on effect of temperature control on shelf-life of fresh agricultural product.  After produce has been pre-cooled, it needs to be transported and put into a cold storage facility where in order to maximize shelf life and quality, it should be stored at it’s optimum storage temperature which varies according to different items making the storage of several items in one facility problematic if multiple storage chambers are not available.  Storage and shelf life depend on intrinsic characteristics of items stored as well as the storage conditions.
viii.    In general, the optimum storage temperature is as low as possible but still above the level of shilling sensitivity of the respective crop.  Another important factor affecting shelf life of fresh produce is the level of relative humidity, impacting water loss, decay, physiological disorders and the uniformity of ripening. Relative humidity level should be high and saturated for most types of produce.
ix.    FAO (2009), reported on the chilling injury for fruits and vegetables, some produce especially on tropical origin, is sensitive to chilling, which means it will incur physiologically damages if stored at a certain time period below a certain temperature but above freezing points.  In general, the longer the time period that produce is exposed to temperature below their level of chilling sensitivity and the lower the temperature, the faster damage will occur.  It should also be noted that effect can be of a cumulative nature, i.e. the time period of storage below the level of chilling sensitivity add up even if produce is stored at optimal conditions in between.  Several factors such as the level of maturity and the level of ripeness at the point of harvest can affect chilling sensitivity.
x.    Wilson et al, (1995) reported that most storage crops required low temperatures and high humidity.  Most fruit and vegetable crops retain better quality at high relative humidity (80 to 95%), but at this humidity, disease growth is encouraged. The cool temperatures in storage rooms help to reduce disease growth, but sanitation and other preventative methods are also required.  Maintaining high relative humidity in storage is complicated by the fact that refrigeration removes moisture (Wilson et al, 1995).  The storage life of fruits and vegetables can be extended greatly by removing the field heat and cooling as soon as possible after harvesting.