Stone fruit Stemming

There may also be cases where the maximum amount of analyte permitted is fixed by law, i.e. statutory limits. For these, there may be laid down standard procedures for sampling. The Codex maximum residue limit for the pesticide cypermethrin is 2 mg kg-1 (at the time of writing) in both citrus fruits and peaches [13]. When preparing the sample for analysis you need to know that in the case of the citrus fruit you take the whole fruit - skin, pith, pips, flesh and juice - whereas in the case of peaches it is the fruit after removal of stems and stones, but the residue is calculated and expressed in terms of the whole commodity (including the stone) without stems [14]. In some instances, it may be necessary to take a certain number of samples and that these must be taken in the presence of a witness. 

Since the middle of the 19 century, heat sterilization in cans and glass jars has been the most important process for fruit preservation. Undamaged, aroma-rich and not overripe fruits are suitable for heat sterilization. Aseptic canning is applicable only for fruit purees. Canned fruits used are primarily stone fruits, pears, pineapples and apples (usually apple puree). Strawberries and gooseberries are canned to a lesser extent. Canned fruits are produced in a large volume by the food industry and also in individual households. Cherries are freed from stone seeds and stems, plums/prunes, apricots and peaches are halved and the stone seeds are removed, strawberry calix is removed, gooseberry and red currant steins are removed, apples and pears are peeled and sliced. Specialized equipment has been developed for these procedures. 

Fig. 5A-C Nonlinear emission spectra measured from A the cell wall of a parenchyma in maize Zea mays) stem B the stone cell of a pear Pyrus serotina R.) fruit C potato Solarium tuberosum L.) starch granule. These spectra were recorded under similar illumination intensity, with normalized 0.1 s integration time. Note the extraordinarily strong SHG from the starch granule...

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