The present study focussed its energy on the evaluation of a dielectric pasteurization for fresh meat. This research investigates ways to reduce the bacterial load on raw beef surfaces with microwave or RF energy in combination with different packaging methods and a natural antimicrobial combination. / Sterilized raw beef cores were inoculated with Escherichia coli biotype 1, Pseudomonas D17 and Carnobacterium "845" of a known inoculum. Treatments were imposed to the cores and packaged in either retail or vacuum packaging. The treatments for the full experiment were RF1 (600W-30s, 400W-30s, 200W-60s), RF2 (600W-30s, 400W-30s, 100W-60s), Nisin-lysozyme alone, Nisin-lysozyme/RF1 and Nisin-lysozyme/RF2. Positive and negative control treatments were added to facilitate the comparison. Microbial analysis, pH measurement, L*a*b* colour measurement and sensory evaluation were performed during the storage period to follow the evolution of the meat samples. / No significant reductions (P < 0.05) in bacterial numbers were observed in this study and none of the treatments showed positive results. Therefore the treatments used would not be considered as a good pasteurization treatment for keeping the quality of raw beef. (Abstract shortened by UMI.)

Four meat spoilage organisms were grown at 4$ sp circ$C for 7 d, in an aqueous extract of meat (Meat Juice Medium), and the levels of various nutrients in the extracts were measured. At an agitation rate of 50 rev$ cdot$min$ sp{-1},$ the four species reached viable counts of 10$ sp8$ Colony Forming Units (CFU)$ cdot$ml$ sp{-1},$ and the order of nutrient utilization was as follows: (1) glucose, (2) gluconate and urea, (3) glycerol, (4) glucose-6-phosphate. Several substrates were still present in the growth medium at the end of the growth period, namely lactate, glucose-6-phosphate and the two unknowns. At a higher agitation rate (100 rev$ cdot$min$ sp{-1}),$ the non-fluorescent pseudomonad reached final counts of ca. 10$ sp{10}$ CFU$ cdot$ml$ sp{-1},$ 2 logs higher than those of the other three organisms present in the mixed culture. The order of nutrient utilization was: (1) glucose, (2) gluconate, urea and glycerol, (3) lactate and glucose-6-phosphate, (4) unknowns 1 and 2. At day 7, none of the nine substrates studied remained in the growth medium.

No description available.

No description available.

This investigation was done with the objective to determine the microbiological load of the main meat products such as: beef, chicken meat, sausage, and viena sausage which are sold in the Riobamba city markets. This investigation was carried out in the Microbiological Laboratory Livestock Science faculty of the Polytechnical Superior school. Specific chemical products were used to determine mesofilas (37 degrees C), xicrofilas (5 degrees C), and termofilas bacteria which did not develop at 45 degrees C, however exicrofilas and mesofilas bacteria were found in every market and meat product in this study. The meat product hygiene is the same in all market conditions. There is no change in the handle or conservation of these products, especially with the handmade products such as sausage and long sausage. My personal point of view is that they are more dangerous for our health because they are not cooked before eaten and because of the way they are conserved. On the contrary, when the meat was cooked, termofilas were not found, since at 50°C temperature, the bacteria begins to be destroyed by the warmth, which give us some confidence to eat cooked food. However, the problem continues because the toxins that the bacteria release are more dangerous, therefore, we must investigate the toxin matter released by the bacteria in the meat products. When meat is eaten, such as hamburgers or roasted meat, there is a risk of acquiring some diseases. The expenses of an investigation of this kind are too high to perform a complete biochemical test which would provide better results that can be relied on. This thesis is patterned to make a project aimed at improvement of the hygiene and quality of these products that are used on a daily basis. In all, the situation in Ecuador is the same as in this city, it is extremely urgent to stress the importance of this issue. The consumption of meat of bad quality is not a good source of nutrition for our people.

No description available.

No description available.

Call number: LD2668 .T4 1985 L43 / Master of Science

Initial experiments were conducted to determine the microbial development in blocks of ground beef. In the top layers of the meat, Pseudomonas spp. predominated. Attempts were made, as well, to measure the microenvironmental changes occurring in ground beef using pH, oxygen, and redox potential micro-electrodes. / Some of the extrinsic (relative humidity, O(,2)), as well as intrinsic factors (pH, redox potential, ions, nutrients) affecting microbial development in aerobically stored meats, were examined. The decrease in glucose levels observed during the aerobic storage of longissimus dorsi (l. dorsi) muscle at 4(DEGREES)C, was accompanied by an increase in the activity of glucose dehydrogenase, and by the appearance of gluconate and 2-ketogluconate on the meat surface. / The attachment of various meat spoilage organisms to l. dorsi muscle was studied. Generally, the pseudomonads attached in higher numbers than the other bacteria, but possessed lower attachment strengths. Investigations on the attachment of two competing organisms to l. dorsi muscle demonstrated that limited competition occurs between the organisms. / A model of the microbial ecology of aerobically stored fresh beef was developed, based on existing evidence. / Various chemicals were added to minced or whole meat to evaluate their effectiveness as food preservatives. As a single compound, potassium sorbate appeared to have the greatest potential as a meat preservative. Meats > into solutions of 5.0% potassium sorbate for 1 min had their shelf-life substantially increased as compared with control samples > into water.

The main objectives of this study can be divided into four categories: a) The determination of the presence of abscesses in carcasses. b) The determination whether the abscesses are area bound. c) The determination of the causative bacteria which is responsible for abscess formation. d) The determination of the economic impact due to carcass rejections and trimmings. The research area consists of the biggest part of the Northern Cape province, which can further be divided into three main production areas, namely Groblershoop, Gordonia and Hantam. The Groblershoop area includes Groblershoop and the surrounding districts. The Gordonia area includes Upington and the Kalahari. The Hantam area includes Calvinia, Springbok and the other districts bordering the areas. All the carcasses were slaughtered at an export abattoir, namely LAW, which is situated in Groblershoop. The Upington veterinary laboratory bacteriologically cultured the abscess material and the results were processed and noted. The following results were prominent: a) It was determined that abscesses did occur in carcasses. b) It was determined that in the Hantam main production area the prevalence of abscesses is the highest, although the slaughter numbers are the lowest. c) It was determined that the bacterium that was responsible for most of the abscesses was Escherichia coli. d) It was determined that the total occurrence of bacteria did not have a significant economic impact, because there were not many carcass rejections due to abscesses. The economic impact, however, of the value of the total rejections, might become a problem.