Sanitation of Fruit and Vegetable Storages

 

Sanitation is critical for the control of bacteria and fungi in packinghouses and cold storages. Therefore, cleaning and disinfecting all parts of the warehouse and storage rooms is required each season. These include: 1) floors, walls, ceilings, doors, and structural beams; 2) refrigeration system components; 3) electrical wires and light fixtures; and 4) air and water pipes, ducts, channels, grates and drains.

The following summary is modified from the Agriculture and Agri-Food technical bulletin: Hygiene Measures in Fruit and Vegetable Storage Warehouses. 1999 E. V. Toussaint, A. Ouimet, O. Carisse, J. DeEll, and C. Vigneault. 4 pp.

Cleaning

Debris on the floor can generally be removed by sweeping. However, vigorous brushing may be required for debris that is on the walls and ceiling. Any remaining dirt and organic matter should be removed with water and detergent. It is important to scour surfaces well enough to dislodge any ground-in dirt. High-pressure washing with a non-foaming industrial detergent is often the easiest method. For safety reasons, electrical systems and motors that are not waterproof should be covered. Cleaning is important because organic matter impedes and/or neutralizes the action of disinfectants. In addition, cleaning removes the substrates that can promote the growth of pathogens in the storage rooms. However, many pathogens will not be removed by simple cleaning and thus disinfectants are required.

Disinfecting

Information on the disinfectants approved for use in Canada is presented in Table 1. Special care should be taken if there is a high rate of contamination, as disinfectants destroy only pathogens on the surfaces. The conditions of application and contact time must be followed exactly in order for any disinfectant to be effective. It is also important to follow the recommended time between disinfectant use, airing of storage rooms, and entry of apples. To give storage rooms a good airing, the doors should be opened and outside air forced in. Storage rooms must be thoroughly ventilated for several days after the use of disinfectants and precautions should be taken to avoid anyone coming into contact with these products by mistake. Disinfectants are often irritating and thus to avoid discomfort and health problems, protective equipment and clothing should be worn when using them, e.g. safety glasses, breathing mask, and waterproof garments. Activated-carbon air filter prevent odors from developing in the storage rooms. It has been suggested that fungicide-based paint be applied to walls for additional protection (Phillips et al., 1979; Lidster et al., 1988). Ozone and UV radiation are not effective at disinfecting storage rooms. Leaving bins, pallets, and other equipment out in the sun and/or strong wind will partially disinfect them. Fumigants can be used to reach the small hidden corners that cannot be reached by conventional methods. However, this method is only effective when used with wet surfaces.

Table 1: Disinfectants approved in Canada for cleaning of fruit and vegetable warehouses (adapted from Toussaint et al., 1999)

 

Compound

Bactericide/
Fungicide
activity

Inactivated by organic matter

 

Corrosive

 

Solution

Exposure
time
(minutes)

 

Advantages

 

Disadvantages

 Hypochlorides
(Javex)

 Effective/
Effective

 Yes

 Yes
(esp. metal)

 10 L per
90 L H2O

 10

 Quick action, low cost

 Odors, irritant, solution must be changed often, discolors some material, pH sensitive, rinsing is necessary

 Quaternary ammonium (10% a.m.)

 Very effective/
Effective

 Slightly

 No

 8-24 mL per L H2O

 10

 Effective at low temp, can be combined with detergents

 Cannot mix with other products, rinsing needed

 Phenolic compounds (hospital disinfectant)

 Very effective/ Very effective

 Slightly

 No

 See label

 10

 Residual action

 Non-volatile residues, rinsing is necessary

 Formaldehyde 37% solution

 Very effective/
Slightly effective

 Yes

 No

 4 L per
100 L H2O

 30

 Broad spectrum action

 Noxious to humans, toxic fumes, must air out room after use, unpleasant odor remains, irritant

Rinsing

The use of some disinfectants result in off-odors, which may result in unpleasant tasting fruit after storage. In addition, the long-acting effect of certain disinfectants can corrode materials within the storage structure and equipment. Therefore, proper rinsing is essential when disinfectants are used. Rinsing involves thoroughly spraying all surfaces treated with disinfectants, starting with high areas so that the residues run down to the floor. Any stagnant water must be removed and it is essential to use water of drinking quality so that the storage will not be re-contaminated.

Drying

The goal of drying is to eliminate humidity, which provides ideal conditions for the development of molds and storage rots. If the disinfectant used does not require rinsing, then drying takes place immediately after disinfecting. Drying involves removing any surplus water and giving the storage rooms a good airing. If outside conditions are hot and dry, then outside air can be forced inside. Maintaining a high temperature and low humidity in the off-season can help to reduce the growth of pathogens in the storage.

** For more detailed information on active ingredients and allowable concentrations please refer to the following document by Health Canada

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For more information:
Toll Free: 1-877-424-1300
Local: (519) 826-4047
E-mail: ag.info.omafra@ontario.ca
Author: Dr. Jennifer DeEll - Fresh Market Quality Program Lead/OMAFRA
Creation Date: 01 August 2007
Last Reviewed: 01 August 2007