Example 5.2 Raw materials for Thai Fermented Sausage (Nham) 1. Meat System: fresh lean pork and pork-skin, held at ambient Thai temperatures for three hours after killing. 2. Curing agents: sodium chloride, sodium nitrate, sodium tripolyphosphate. 3. Seasonings: white pepper, fresh garlic. 4. Carbon sources for fermentation: jasmine rice (cooked), glucose. 5. Starter cultures: Lactobacillus plantarium, Lactobaccillus brevis, Pediococcus cerevisiae, Micrococcus varians. 6. Sausage casings: cylindrical tubes, 22.5 mm diameter, 30 cm long, made from laminated 15 micron uncoated nylon and 50 micron linear low density polyethylene. Limits on raw materials Meat system was set at 80% ground meat 20% sliced pork skin. The low and high levels for the other ingredients and starter cultures were: Raw materials % meat system Starter Cultures cfu/g meat system sodium chloride 1, 4 Lactobacillus plantarium 0, 106 sodium nitrate 0.01, 0.03 Lactobacillus brevis 0, 106 sodium tripolyphosphate 0, 0.5 Pediococcus cerevisiae 0, 106 minced garlic 3, 7 Micrococcus varians 0, 106 white pepper 0, 0.05     cooked rice 5, 8     Screening experiments A Plackett and Burnam experimental design was used to screen these raw materials. From this, the important raw materials affecting the qualities of the Nham were identified as the four starter cultures and the rice, and in further experiments these were studied at different levels and under different processing conditions. Glucose as another carbon source was also studied. The other ingredients were fixed: sodium chloride 3%, sodium nitrate 0.02%, sodium tripolyphosphate 0.3%, garlic 7.0%, white pepper 0.05%. Wiriyacharee, P. ( 1990) The systematic development of a controlled fermentation process for Nham, a Thai semi-dry sausage, Ph.D. thesis, Massey University, New Zealand

In formulation studies, the important development in the last ten years has been the use of the computer.

First, there is the raw material database on the computer; this started by detailing the chemical and nutritional compositions of different raw materials but has expanded to other properties such as microbiological quality, sensory qualities and to the effects of raw materials in processing, where this information is available. For companies with a narrow range of products, this raw materials database can be used in all product development projects as a starting point for formulation; in other companies with a wide-ranging product mix there may be need for two or three databases. The database is only useful if it is kept up-to-date and is also related to the company's buying policy.

The database can be used to build and analyse various formulations to see how they fit the criteria for the product qualities, the costs and the processing. This can be done quite simply using computer spreadsheets. There are also expert systems available which provide a decision support framework made up of two parts: a task part containing the distinct problem-solving steps involved in creating a formulation, and a physical part with the specific knowledge about the properties of the raw materials and the processes involved. As more information is obtained from factorial experimentation, mathematical relationships between the raw materials in the formulation and the product qualities are developed and these can be used in such techniques as linear programming.

Think Break 5.6 Product formulation: natural fruit ice cream For developing a formulation for natural fruit ice-cream, identify the important raw material variables and the important product qualities. Relate each raw material to a product quality(ies); for example, lecithin, an emulsifying agent, stabilises the oil/water emulsion and gives smoothness to the ice-cream. See: The Science of Ice Cream by Chris Clarke, 2004, Published by the Royal Society of Chemistry.