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PENGENDALIAN MIKROBIA DENGAN PEMANASAN. PENGELOMPOKAN MIKOBIA ATAS DASAR RENTANG SUHU PERTUMBUHANNYA [˚C] KELOMPOKMINIMUMOPTIMUMMAKSIMUM THERMOPHILES.

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Presentasi berjudul: "PENGENDALIAN MIKROBIA DENGAN PEMANASAN. PENGELOMPOKAN MIKOBIA ATAS DASAR RENTANG SUHU PERTUMBUHANNYA [˚C] KELOMPOKMINIMUMOPTIMUMMAKSIMUM THERMOPHILES."— Transcript presentasi:

1 PENGENDALIAN MIKROBIA DENGAN PEMANASAN

2 PENGELOMPOKAN MIKOBIA ATAS DASAR RENTANG SUHU PERTUMBUHANNYA [˚C] KELOMPOKMINIMUMOPTIMUMMAKSIMUM THERMOPHILES MESOPHILES PSYCHROPHILES PSYCHROTROPH – 15 (- 5) – 5 (- 5) – – – – – –

3 PENGARUH SUHU TERHADAP WAKTU GENERASI mesophile psychrophile DASAR PENGENDALIAN

4 HEAT INDUCED CHANGE IN THE CELL SURFACE AND MEMBRANE*) OUTER MEMBRANE INNER MEMBRANE CYTOPLASM BLEBS The bar in ea The bar in each micrograph represents 0.5µm *) Katsui, et al, 1982

5 PENYEBAB KEMATIAN SEL KARENA PEMANASAN – RUSAKNYA SISTEM METABOLISME  KEHILANGAN KEMAMPUAN UNTUK MEMPERBANYAK DIRI KERUSAKAN MEMBRAN SEL : sifat permiabilitasnya hilang “leakage” senyawa intraseluler kehilangan ion Mg  degradasi RNA dan ribosoma kehilangan ensim periplasmik (alkali fosfatase) kehilangan ensim sitoplasmik (glukosa 6 fosfat dehidrogenase) PERUBAHAN FUNGSI SENYAWA SELULER  DENATURASI PROTEIN ( inaktivasi ensim) KERUSAKAN DNA

6 FAKTOR-FAKTOR YANG MEMPENGARUHI KETAHANAN PANAS BAKTERI Sifat yang melekat pada individu sel Kondisi pertumbuhan SuhuMedium Recovery medium (minimal or enriched medium) Lingkungan selama pemanasan Kompoisis makanan Bentuk pangan (padat, cairan) Aktivitas air Ukuran bahan yang dipanaskan pH bahan  Low Acid food (pH above 4.6) didasarkan pada ketidakmampuan C. Botulinum untuk tumbuh pada pH 4.6 atau lebih rendah dari 4,6 didasarkan pada ketidakmampuan C. Botulinum untuk tumbuh pada pH 4.6 atau lebih rendah dari 4,6  Acid food  Acid food

7 Mechanism the dead of cell subjected to heat Damage in cell membrane and cell wall Leakage of cell component Denaturation of protein ( enzymes )  cell metabolism stopped Denaturation of one gene essential to reproduction (Rahn, 1929) Log Number of cells Heated ( min) at t˚C The Rate of Dead of Bacteria  Logaritmic

8 Log Number of cells Heated ( min) at t˚C Dead of cells  Logaritmic Activation Consist of two strains BEBERAPA PENYIMPANGAN YANG MUNGKIN TERJADI

9 Log Number of cells D D D Heated ( min) at t˚C Graphical illustration of decimal reduction time D RATE OF DESTRUCTION Nilai D t : waktu pemanasan (menit) yang diperlukan untuk mengurangi populasi sebanyak 90% pada suhu t˚C D > D > D

10 TEMPERATURE (˚C) D VALUE (MINUTE) z value z value = ˚C required for thermal death time curve to transfer one log cycle Graphical illustration of Thermal Death Time curve D 80 = 10 minutes D 93 = 1.0 minute

11 PROBABILITY OF SURVIVAL t = D (log a – log b) t = D (log a – log b) t = time, in minutes, of heating at a constant lethal temperature D = time, in minute, to kill 9)% of the cells in the population D = time, in minute, to kill 9)% of the cells in the population a = initial number of viable cells in the population a = initial number of viable cells in the population b = number of viable cells in the population after time t b = number of viable cells in the population after time t Examples : assume that there is 1 spore of C.botulinum in each of containers, and D 250 is Time temperature combinations is 2.52 minutes at 250˚F. If all container are given the same process, how many should spores be expected survive?  2.52 = 0.21(log log b) log b= 0  b = 1 log b= 0  b = 1 Tell us that 1 container of the should not be sterillized by the process.

12 Approximate resistance of some bacterial spore to heat*) Bacterial species Food class D value 120˚C D value 100˚C D value 80˚C Z value (˚C) Thermophilic anaerob Clostridium thermosachariliticum C. Nigricans Thermophilic aerob Bacillus stearothermophilus B. coagulans LA A Mesophilic anaerob C. sporogenus(include.PA3679) C. botulinum (type A and B) C. perfringens C. histolyticum C. pateurianum C. subterminate LA Mesophilic aerob Bacillus cereus B. licheniformis B. megaterium B. subtilis B. macerans LA A *)The International Commission on Microbiological Specifications for Foods (ICMF)

13 LOW-HEAT PROCESSING (Pasteurization) To destroy all vegetative cells f the pathogen and a large number of associative (spoilage) microorganisms LTLT (low temperature long time); HTST ( high temperature short time)? HIGH-HEAT PROCESSING (heating at or above 100ºC) pH>4,6  12D concept (Cl. butulinum tipe A dan B) the most resistant spores of pathogen. For spoilage studies: Bacillus stearothemophylus. pH < 4,6  spore forming B. coagulans, aciduric non- spore forming : lactobacillus dan Leuconostoc UHT : 150ºC for 2 to 3 sec. MICROWAVE HEATING Can not considered safe from pathogen  is not heated uniformly and some areas remain cold

14 38˚C 73˚C 88˚C 53˚C 21˚C 13˚C -0.5˚C Balance tank Silo tank 88˚C A two-way regeneration system used in juice processing Heating section 2.Regeneration section 3.Cooling with water 4.Cooling with chilled water 5.Cooling with glycol Automatic valve


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