PENGENDALIAN MIKROBIA DENGAN PEMANASAN

1. PENGENDALIAN MIKROBIADENGAN PEMANASAN

2. PENGELOMPOKAN MIKOBIA ATAS DASAR RENTANG SUHU PERTUMBUHANNYA [˚C]

3. DASAR PENGENDALIAN PENGARUH SUHU TERHADAP WAKTU GENERASI psychrophile mesophile

4. HEAT INDUCED CHANGE IN THE CELL SURFACE AND MEMBRANE*) INNER MEMBRANE OUTER 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 Suhu Medium 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  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) 8 7 The Rate of Dead of Bacteria Logaritmic Log Number of cells 6 5 1 2 3 4 5 6 7 Heated ( min) at t˚C

8. BEBERAPA PENYIMPANGAN YANG MUNGKIN TERJADI 8 Activation 7 Dead of cellsLogaritmic Log Number of cells 6 Consist of two strains 5 1 2 3 4 5 6 7 Heated ( min) at t˚C

9. RATE OF DESTRUCTION Nilai Dt : waktu pemanasan (menit) yang diperlukan untuk mengurangi populasi sebanyak 90% pada suhu t˚C 8 7 D > D > D Log Number of cells 6 5 D D D 1 2 3 4 5 6 7 Heated ( min) at t˚C Graphical illustration of decimal reduction time D

10. 8 z value = ˚C required for thermal death time curve to transfer one log cycle 10 D80 = 10 minutes D93 = 1.0 minute D VALUE (MINUTE) 1 z value 0.1 80 90 100 TEMPERATURE (˚C) Graphical illustration of Thermal Death Time curve

11. PROBABILITY OF SURVIVAL 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 a = initial number of viable cells in the population b = number of viable cells in the population after time t Examples : assume that there is 1 spore of C.botulinum in each of 1012 containers, and D 250 is 0.21 . 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 1012 - log b) 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*) *)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. A two-way regeneration system used in juice processing Automatic valve 88˚C 21˚C -0.5˚C 13˚C 53˚C Silo tank 5 4 2 3 1 73˚C 88˚C 38˚C • Heating section • Regeneration section • Cooling with water • Cooling with chilled water • Cooling with glycol Balance tank