A comparison of the cooking performance of different appliances when following food manufacturers' instructions
The purpose of this research was to measure the temperature achieved in, and the microbiological count of, chicken burgers cooked following the preparation instructions given by the manufacturers. The work investigates the cooking of chicken burgers, manufactured by four different companies, cooked at different positions under a grill. Three appliances were used. Each showed uneven distribution of heat and a hot position and cool position was established for each grill. Differences in the temperature of the burgers cooked at different positions on the grills were also found. The burgers at the cool position attained a much lower cooking temperature and had a higher number of microorganisms surviving the cooking. The grill that produced the highest temperatures in the burgers had the lowest number of organisms surviving in the burgers. Only 24 out of the 72 burgers cooked to the manufacturers' instructions attained temperatures above 70°C. Some of the burgers appeared to be cooked when visibly assessed, but the core temperatures were low and had high microbial counts. The results obtained indicate that not all the cooking instructions were satisfactory and not all the appliances performed satisfactorily.
Destruction of Microorganisms During Thawing of Skim Milk.
The viability of four species of microorganisms ( Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa and Saccharomyces cerevisiae ) during rapid and slow thawing of frozen milk was investigated. Results indicated that the destruction of microbial cells was significantly greater when skim milk was thawed slowly. Recovery of viable organisms by plating was generally slightly higher when peptone water was used as a diluent, although differences were not statistically significant.
Linear Programming in the Allocation of Milk Resources for Cheese Making
Abstract To use linear programming, the cheese making process can be modeled as a resource conversion process. The relationship between input milk resources and output products can be analyzed using mass balance assumptions. The variables used in the linear programming model will represent the pounds of each milk resource chosen to formulate a vat of cheese milk. Additional variables will be used to represent the pounds of cream to be removed from a milk resource that has the potential to have cream removed. Three objectives that could be considered are 1) maximize net returns, 2) maximize cheese yield, or 3) minimize cost. A hypothetical example is used to illustrate how the cheese making process can be modeled. This linear programming model depends on formulas that relate ratio of casein to fat of milk to the fat on the dry basis of the cheese. Sensitivity analysis is performed to determine at what cost a milk resource not in the optimal formulation will replace a milk resource currently in the optimal formulation. The linear programming model can be an effective management tool in the allocation of milk resources for cheese making.