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Laundry Trial

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BACKGROUND:

It is mentioned in the Australian Standard (AS/NZS 4146:2000) that commercial and industrial laundries process work from a wide variety of end users including manufacturing, food processing, entertainment, catering, accommodation and health care providers. The risks associated with laundering hospital linen, quilts, curtains plastic sheeting and other textiles are generally identified, and appropriate procedures for handling the risks are widely used. The risks in the non-hospital area are not always identified. Risks to health from non-hospital laundry work may in fact be greater than that associated with hospital work. For example, items such as hotel and motel bed linen are not subject to the infection control procedures that apply in health care establishments following change of occupant; Salmonella infection is a risk in some food processing industries while many industrial garments are contaminated with a variety of harmful substances. Because of the potential risk, the requirements for infection control in laundries processing non-hospital linen should be as stringent as those for hospital laundries.
 
Although soiled textile articles have been identified as a source of pathogenic microorganisms, the risk of disease transmission is negligible if hygienic and commonsense storage and handling of clean and soiled articles is practiced. In this regard, it is intended that standard precautions be applied to the handling of soiled articles. That is, it is to be assumed that all soiled articles are a potential source of infection and therefore appropriate precautions are to be applied including the use of protective attire
 
AS/NZS 4146 specifies general laundry practice requirements and recommendations for commercial, industrial, hospital, institutional, on-premise and coin-operated laundries, as well as minimum performance requirements which are to be attained in order to provide an acceptable level of service. This Standard is intended to provide laundry operators as well as their clients with a common reference for acceptable laundry performance.
 

LAUNDRY VALIDATION TRIAL:

The Australian Standard AS4146 describes the general laundry practice requirements for commercial, industrial, hospital, institutional and coin operated laundries.  A key element of the standard pertains to the microbiological outcomes required for laundering processes.
 
The principle utilized in this standard is that thermal disinfection processes are relatively well understood and considerable scientific literature exists on the ability of temperature to kill microorganisms.  Thus very specific thermal wash cycle conditions are prescribed by this standard.  The ability of any laundry to comply with these thermal disinfection processes is a relatively easy task.
 
Laundry trials are performed as per AS4146 requirements and are designed to demonstrate the effectiveness of a clothes washing cycle in removing and /or killing bacteria.  A kill claim cannot be made from the data generated from this test since the protocol does not allow for differentiation between killing the bacteria and removing them by detergent/mechanical action.  The protocol is suitable for comparative performance testing of different wash cycles, chemicals and conditions.

VERIFICATION TESTING OF LAUNDERED GOODS:

AS4146 does not prescribe a microbiological standard for finished laundered goods.
 
In the standard two examples are given of possible microbiological outcomes after laundering. 
 
The first of these examples is an illustration which implies that bacteria counts of less than 5 organisms per cm2 can typically be achieved in hospital linen.  However, the details of the microbiological method of analysis of the linen are not described.
 
The second example is a reference to the use of a particular type of microbiological technique cited as being suitable for assessing effectiveness of the process.  This technique is the contact plate.  A bacteria count of less than 1 organism per cm2 is stated as a suitable bacterial level as measured by this technique.
 
In the absence of a prescribed microbiological standard it is understandable that such examples have the ability to become the defacto standard.  However, it should not be promoted as such either by the industry or the chemical companies marketing laundry chemicals.

 

METHOD REFERENCE:

  1. Australian Standard (AS) 4146

SAMPLE REQUIREMENT:

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TURNAROUND TIME:

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