TEST METHODS FOR MEASURING MINIMUM HOLDING TIMES IN CONTINUOUS EGG PASTEURIZERS1

Two test methods that may be used in commercial egg pasteurizers while in normal operation are described. Either may be used without damage to the product and with almost no disturbance to regular plant procedures. These tests have been needed to help determine the degree of compliance with pasteurization requirements. The first method requires injection of a cold shot into the flow stream entering the holding tube and determination of the time required for the first of this material to arrive at the outlet of the holding tube. The cold shot is introduced into the line by use of a by-pass loop. The arrival of the cold shot at the end of the holding tube is detected by use of a sensitive recorder to indicate the temperature change. The second method is based on the use of a fluorocarbon compound as a tracer. The compound is dissolved in yolk, which is injected into the flow stream entering the holding tube. Samples taken at the end of the holding tube are checked with a fluorocarbon leak detector of the type used in the refrigeration industry. The first positive sample is taken as the time of arrival of the injected tracer. Fluorocarbon compound 12 which is permitted in the immersion freezing of foods may be used and has no effects on the functional properties of the products.

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Scientific and Standardization Committee Communications Comparison of Test Methods for the Lupus Anticoagulant: International Survey on Lupus Anticoagulants-I (ISLA-1)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647340 ◽

1990 ◽

Vol 64 (03) ◽

pp. 478-484 ◽

Cited By ~ 28

Author(s):

Thomas Exner ◽

Douglas A Triplett ◽

David A Taberner ◽

Margaret A Howard ◽

E Nigel Harris

Keyword(s):

Lupus Anticoagulant ◽

Test Methods ◽

Positive Sample ◽

Direct Proportion ◽

Clotting Time ◽

Preliminary Screening ◽

Activated Platelets ◽

Tissue Thromboplastin ◽

Kaolin Clotting Time ◽

Induced Defects

SummarySix lyophilized plasma samples were sent to 20 “expert” laboratories for assessment of lupus anticoagulant (LA). Four samples contained pooled LA of graded potency mixed with aged normal plasma. One contained LA plus cephalin phospholipid and one contained a nonspecific venom anticoagulant. Sixteen methods were used overall with some participants using up to 8 methods. Results were scored in regard to the known potencies of LA in the samples and other known induced defects.Activated partial thromboplastin time (APTT) tests used by most participants for preliminary screening were relatively sensitive, but non-specific. Platelet or phospholipid neutralization procedures (PNP) appeared to be sensitive and specific but showed a non-linear response to increased LA content. Kaolin clotting time (KCT) tests showed the most sensitive response to increased LA content but the weaker LA were not scored as abnormal by most laboratories as the samples may have contained platelet fragments. Other commonly used tests such as the tissue thromboplastin inhibition (TTI) test and the dilute Russell’s viper venom test (DRVVT) were carried out somewhat inconsistently. The variability in performance of tests in different laboratories indicates that standardization of methodology is urgently required.Generally it seemed that most clotting tests were “bypassed” by the addition of phospholipid to a known LA-positive sample in apparently direct proportion to their sensitivity. Sample preparation, especially prevention of contamination with activated platelets is a vital preliminary part in the assay of LA.

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