The CONTROL of micro-organisms in the FOODSTUFF

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The control of micro-organisms in the foodstuff from the animal must be carried out if we wanted this foodstuff to be not fast broken or fast became rotten, but became durable. Foodstuff damage that was caused by micro-organisms happened because of these micro-organisms bred and bermetabolisme in such a way as the foodstuff experienced the change that caused his use as the foodstuff to was disturbed. The process of this damage was enabled because of the foodstuff to have the condition for the growth of micro-organisms. Therefore, foodstuff damage could happen if being available the substrate (that is the foodstuff tsb. ) that agreed, afterwards the foodstuff was dirtiest by micro-organisms and had the opportunity for mikroroganisme to breed. Control efforts of micro-organisms could be carried out if factors that influenced the growth or the proliferation of micro-organisms was known beforehand. Factors that influenced this generally was divided in five discussions that is a) generation time; b) the intrinsic factor; c) the extrinsic factor; d) the process factor and e) the implicit factor.

a.Time generation

Generation time was time that was needed by micro-organisms to increase the number of cells to twice the number fold originally. The growth curve of micro-organisms consisted of four phases that is the adjustment phase (lag phase), the exponential phase or the phase logaritmik, the stationary phase and the death phase. In the exponential phase the increase in the number of cells happened and was used to to determine generation time. Several examples of generation time in the temperature of the growth that was optimal including 30 minutes during Bacillus cereus, 20 minutes for Escherichia coli and Salmonella, and 10 minutes for Clostridium perfringens.

b. The intrinsic factor

The intrinsic factor covered the pH, the activity of water (activity of water, aw), the capacity oxidised-reduction (redoxpotential, Eh), the content of the nutrient, the material antimikroba and the structure of the foodstuff. The measurement of the acidity or the pH was log10 the concentration of the hydrogen ion. Usual him the bacteria grew in the pH around neutral (6.5 – 7.5) whereas mildew and yeast in the pH 4.0-6.5.The activity of water (aw) was the comparison between the pressure of solution vapour and the solvent steam pressure pure in the same temperature (aw = p/po). This was the amount of water that was available for the growth mikrobia in food and not meant the number of the total water that was contained in the foodstuff because of the existence adsorpsi in the constituents was not protracted and the absorption by the protracted constituents (mis. sugar, salt). Pure water had aw 1.0 and the foodstuff that fully terdehidrasi had aw = 0. The bacteria Gram the negative was more sensitive to the decline aw was compared by the other bacteria. The limit aw minimal for multiplication of most bacterium was 0.90. Escherichia coli needed aw minimal of 0.96, whereas Penicillium 0.81. Nevertheless aw minimal for Staphylococcus aureus was 0.85. Several elements in the foodstuff had the characteristics antimikroba. Cattle milk contained laktoferin, konglutinin, lisozim, laktenin and the system laktoperoksidase. The material antimikroba in the egg was lisozim, konalbumin, ovomukoid, avidin. The system laktoperoksidase consist of laktoperoksidase, tiosianat and peroksidase. The three components were needed for the effect antimikroba. Goat milk contained more lisozim was compared cattle milk. Nevertheless the content lisozim milk was lower when compared with white the egg. Laktoferin was protein penangkap Fe in milk and could be compared with konalbumin white the egg. Lisozim that was met in the egg caused lisis the layer peptidoglikan the wall of the bacterial cell. The uterus lisozim in the egg was 3.5 %. The structure of the foodstuff that could influence the growth of micro-organisms for example carcass fat and skin to the poultry carcass and the carcass the pig could protect meat from contamination of micro-organisms. The egg eggshell that had pores of 25-40 ┬Ám could make the entry more difficult mikroorganisne in the egg although could not prevent continue to the entry of micro-organisms. Micro-organisms will be kept by the layer of the membrane in that prevented the entry of micro-organisms to albumen. Meat rolled or meat that has been cut into the part was more insignificant more will give the ease for micro-organisms to breed compared with to carcass meat.

c. The extrinsic factor

The extrinsic factor that influenced the growth of micro-organisms was the temperature of the storage and the other outside factor that in principle was connected with the influence atmosferik like humidity, the gas pressure/the existence of gas, also the light and the influence of ultraviolet rays. Was based on his optimum temperature, micro-organisms were divided to psikrofil with the optimum temperature less than + 20 °C, mesofil (+20° s/d + 40 °C) and termofil (more than +40 °C). In the minimal temperature the change in the cell membrane happened so as to the transport of nutrients not happen. On the other hand in the temperature of the maximum happened denaturasi the enzyme, protein damage and lipida to the cell membrane that caused lisis him micro-organisms. Pathogen micro-organisms usually including into the group mesofil. The influence of the low temperature in mesofil was inaktivasi and the change in the structure of protein permease. Mildew had the range of the growth that was wider compared with the bacteria, whereas well-off yeast the body in the range psikrofil and mesofil. Micro-organisms could be also classified according to his resistance towards the temperature that did not benefit that is psikrotrof (grew in the temperature less than + 7 °C) and termotrof (grew in the temperature more than + 55 °C). Environmental humidity (relative humidity, RH) important for aw the foodstuff and the growth of micro-organisms to the surface of the foodstuff. Storage space that had RH low will cause the foodstuff that was not packed to experience the drought to his surface and therefore changed the value of the activity airnya.Produk this dry foodstuff when being brought to the humid environment (RH high) will absorb humidity so as his surface could be overgrown the fungus. The same thing will happen when the foodstuff that was cooled down was carried to the warmer environment. This will cause water condensation in his surface part. This process was important to be paid attention to in the packing of the product that could rot, because usually packing space is warmer compared with cooling space, so as to be formed by the thin layer of condensation water. This will cause the increase in the activity of water that in turn could facilitate the growth of micro-organisms. The storage of the foodstuff in space was open increased the level of CO2 until 10 % that could be reached by adding dry ice (CO2) solid. Penghambatan by CO2 increased in line with the decline in the temperature because solubilitas CO2 increased in the low temperature. The bacteria Gram the negative was more susceptible to CO2 was compared by the bacteria Gram positive. Pseudomonas most susceptible whereas the bacteria as well as the anaerobe bacteria of lactate acid most kept. The existence of the light and the ultra rays violet could influence the growth of micro-organisms and damage toxin that was produced by him, for example to Aspergillus ochraceus.

d. The factor proses

All the processes of processing technology of the foodstuff changed the micro environment this foodstuff. This process could take the form of the heating, drainage, the modification of the pH, penggaraman, curing, fumigation, irradiation, the high pressure, the use of the electrical field and giving of the food flux.

e. The factor implisit

The factor implisit The other factor that played a role in being the implicit factor that is the existence sinergisme or antagonism among available micro-organisms in “lingkungan” the foodstuff. When micro-organisms grew to the foodstuff he will compete to receive space and the nutrient. Therefore the interaction among different micro-organisms will happen. This interaction could support each other and hindered each other (happened sinergisme or antagonism).

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