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By carefully designing the medium to contain selective agents, and diagnostic compounds which will give a strong signal when the ...

tubes can detect as little as 10^2 –10^3 fg (fg¼femtogram¼ 10 ^15 g) which corresponds to as few as 10^2 –10^3 bacterial cells. ...

10.6 RAPID METHODS FOR THE DETECTION OF SPECIFIC ORGANISMS AND TOXINS 10.6.1 Immunological Methods Because of the potential spec ...

immunoassays. While striving for antibodies that are sufficiently broad in their specificity to recognize all strains of the des ...

former being suitable for recognition at the genus level whereas the latter may be considerably more specific. Although RNA is a ...

stranded DNA into single strands. The mix is then cooled to 37–65 1 Cto allow the primers to anneal to the single strands and th ...

four, eight, sixteen and so on so that after 20 cycles approximately 10^6 copies can be generated from the original. Two key com ...

by amplification of a shorter sequence within the amplicon using a second set of inner primers.  Reverse transcriptase PCR whic ...

In restriction fragment length polymorphism (RFLP), a restriction enzyme is used to cut DNA into a number of fragments depending ...

which do not set a particular level of quality or competence to be achieved (see Section 11.7). There are also schemes of labora ...

CHAPTER 11 Controlling the Microbiological Quality of Foods In Chapter 10 we surveyed the different methods used in the microbio ...

Regulatory bodies and the food industry are the two groups most actively interested in determining and controlling the microbiol ...

(4) The number and size of samples to be taken from a batch of food or from a source of concern such as a point in a processing ...

As the number of samples tested increases, so does our confidence in the result but so too does the cost of testing. To be sure ...

acceptable), then the probability distribution of the various possible outcomes is given by the expansion of the binomial: ðpþqÞ ...

corresponding to 40 positive 25 g samples in a lot of 1 tonne (400025g samples), then the lot would be accepted 90% of the time ...

The ideal OC curve would resemble Figure 11.5 with a vertical cut off at the maximum acceptable level of defectives. To achieve ...

unacceptable. Use of this extra classification of marginally acceptable means that they are not used with presence or absence te ...

surface with axes defining the probability of acceptance/rejection, the proportion of marginally defectives in a lot, and the pr ...

themselves and they do not (with a few exceptions) specify any minimum frequency of testing, increased routine testing or the in ...