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Once the test portion is removed from the ground laboratory sample, the mycotoxin is extracted by blending a solvent with the comminuted test portion. Before the mycotoxin can be quantified in the solvent extract, analytical methods usually consist of several steps related to removing interfering compounds (i.e. oils) and concentrating the mycotoxins for quantification. These steps include centrifugation,...
The only way to achieve a more precise estimate of the true lot concentration is to reduce the total variability of the mycotoxin test procedure. The total variability of the test procedure can be reduced by reducing the variability associated with each step of the mycotoxin test procedure. Increasing the size of the laboratory sample can reduce the sampling variability. The sample preparation variability...
Procedures used to take a sample from a bulk lot are extremely important. Every individual item in the lot should have an equal chance of being chosen (called random sampling). Biases are introduced by sample selection methods if equipment and procedures used to select the sample prohibit or reduce the chances of any item in the lot from being chosen. Examples of bias in the sample selection process,...
Because of the variability among laboratory sample test results, two types of mistakes are associated with any mycotoxin-sampling plan. First, good lots (lots with a concentration less than or equal to the legal limit) will test bad and be rejected by the sampling plan. The chances of making this type of mistake is often called the seller’s risk (false positives or type I, α error) since these lots...
Mycotoxins are chemically and biologically active secondary metabolites from several families of saprophytic and plant pathogenic moulds such as Fusarium, Aspergillus, Penicillium, Alternaria, and Claviceps spp. that grow on cereals, nuts, beans and many other agricultural crops including many fruit crops (Cullen and Newberne 1994). Mycotoxin residues in animal tissues, e.g. kidneys, and animal products,...
Once an aggregate sample has been collected and the laboratory sample withdrawn (if the aggregate sample is larger than the required laboratory sample), the laboratory sample must be prepared for mycotoxin quantification. Since it is not practical to extract the mycotoxin from a large laboratory sample, the mycotoxin is usually extracted from a much smaller portion of product (test portion) taken...
Because of the uncertainties (biases and variability) associated with a mycotoxin test procedure, it is impossible to determine with 100% certainty the true concentration of a bulk lot. Even when the sample is correctly selected (no biases), there will be variability associated with the mycotoxin test procedure. The variance associated with a mycotoxin test procedure is the sum of sampling, sample...
There is always some level of uncertainty (variability) associated with any sampling plan. Because of this, the true mycotoxin concentration of a bulk lot can’t be determined with 100% certainty; nor can all lots be correctly classified into good and bad categories (based upon some legal limit) with 100% accuracy. Accuracy and precision are two types of uncertainties associated with a sampling plan...
It is important to be able to detect and quantify the mycotoxin concentration in foods and feeds destined for human and animal consumption. In research, quality assurance, and regulatory activities, correct decisions concerning the fate of commercial lots can only be made if the mycotoxin concentration in the lot can be estimated with a high degree of accuracy and precision. The mycotoxin concentration...
Even when using accepted sampling, sample preparation, and analytical procedures (Campbell et al. 1986; Malone 2000; Dickens and Satterwhite 1969; Association of Official Analytical Chemists 1990; Nesheim 1979; Steyn et al. 1991), there are errors (the term error will be used to denote variability) associated with each of the steps of the mycotoxin test procedure (Whitaker et al. 1972, 1974, 1976,...
Once the mycotoxin concentration is quantified, the concentration value is used to estimate the true lot concentration or is compared to an accept/reject limit (ARL). The ARL is a predefined threshold concentration, usually equal to a legal limit used in regulatory applications. If the mycotoxin concentration in a test portion taken from a laboratory sample is less than or equal to the ARL, the lot...
A study was carried out to evaluate the performance of sampling plans to determine fumonisin in maize produced and marketed in Nigeria, Africa (Whitaker et al. 2007). A total of 86 food-grade maize lots intended for human consumption were sampled in 2002 from five regions in Nigeria. From each lot, a 2 kg ‘aggregate’ sample was taken, comprising 20 laboratory samples of 100 g each. Each laboratory...
Synthetic methylotrophy is the development of non-native methylotrophs that can utilize methane and methanol as sole carbon and energy sources or as co-substrates with carbohydrates to produce metabolites as biofuels and chemicals. The availability of methane (from natural gas) and its oxidation product, methanol, has been increasing, while prices have been decreasing, thus rendering them as attractive...
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