Food & Drugs Preservation

Food & Drugs Preservation

Faktor yang mempengaruhi pertumbuhan MO Dr.rer.nat. Yosi B. Murti

Preservasi obat dan makanan

Delays product spoilage

Extends life of the product

Improves product quality

Dr.rer.nat. Yosi B. Murti

Factors Affecting Growth

Microorganisms, like other living organisms, are dependent on their environment to provide for their basic needs. Adverse conditions can alter their growth rate or kill them. Growth of microorganisms can be manipulated by controlling:

Nutrients available Oxygen Water Temperature Acidity and pH Light Chemicals Dr.rer.nat. Yosi B. Murti

Nutrients

Nutrients such as carbohydrates, fats, proteins, vitamins, minerals and water, required by, man are also needed by microorganisms to grow. Microbes differ in their abilities to use substrates as nutrient sources. Their enzyme systems are made available according to their genetic code. They vary in ability to use nitrogen sources to produce amino acids and, therefore, proteins. Some require amino acids to be supplied by the substrate. When organisms need special materials provided by their environment, we refer to them as fastidious. Difference in the utilization of nutrients and the waste products they produce are important in differentiating between organisms. Dr.rer.nat. Yosi B. Murti

Nutrients-Food

Food products (meat, milk, fruit, vegetables, etc.) are high in nutrients proteins, carbohydrates, fat, phosphorus, minerals, and water Food products are an excellent source of nutrients to support microbial growth


Oxygen

Microbes also differ in their needs for free oxygen. Aerobic organisms must grow in the presence of free oxygen and anaerobic organisms must grow in the absence of free oxygen. Facultative organisms can grow with or without oxygen, while microaerophilic organisms grow in the presence of small quantities of oxygen.


Water

Water is necessary for microbes to grow, but microbes cannot grow in pure water. Some water is not available. A measurement of the availability of water is aw or water activity. Measure of the “free” water available for growth Scale = (no water) 0 to 1.0 (lots of water)

a saturated salt solution is 0.75. Most spoilage bacteria require a minimum aw of 0.90. Some bacteria can tolerate an aw above 0.75 as can some yeasts and most molds. Most yeasts require 0.87 water activity. An aw of 0.85 or less suppresses the growth of organisms of public health significance.


Temperature

Microorganisms can grow in a wide range of temperatures. Since they depend on water as a solvent for nutrients, frozen water or boiling water inhibits their growth. General terms are applied to organisms based on their growth at different temperatures. Most organisms grow best at or near room and body temperature. These are mesophiles. Those growing above 40°C are called thermophiles while those growing below 25°C are called psychrotrophs. Dr.rer.nat. Yosi B. Murti


Acidity The nature of a solution based on its acidity or alkalinity is described as pH. The pH scale ranges from 0, strongly acidic, to 14, strongly basic. Neutral solutions are pH 7, the pH of pure water. Most bacteria require near neutral conditions for optimal growth with minimums and maximums between 4 and 9. Many organisms change the pH of their substrate by producing by-products during growth. They can change conditions such that the environment can no longer support their growth. Yeasts and molds are more tolerant of lower pH than the bacteria and may outgrow them under those conditions.


Light & Chemicals

Ultraviolet light and the presence of chemical inhibitors may also affect the growth of organisms. Many treatments such as hydrogen peroxide and chlorine can kill or injure microbes. Under certain conditions those given a sublethal treatment are injured, but can recover.


Contoh perkembangan bakteri dengan doubling time 20 menit



Types of Preservation Techniques

Freezing Cooking & Pasteurization Dehydration Chemical Fermentation Irradiation Canning Food preservative


Contoh Pengendalian pertumbuhan MO

Penggaraman: ikan asin Pembekuan: produk-produk daging Pasteurisasi: perebusan pada suhu 70°C untuk produk susu segar. UHT ultra high temperature pasteurization produk susu dipanaskan suhu tinggi dalam waktu singkat Pengawet (preservatif): banyak digunakan utk produk makanan dan sediaan farmasi, cth: ascorbat dan benzoat. Sterilisasi: terutama untuk makanan dalam kaleng dan sediaan farmasi: uap panas bertekanan, radiasi gamma, dan gas (etilen dioksid) Dr.rer.nat. Yosi B. Murti

Pengaruh pendinginan terhadap pengawetan



Sel-sel masih hidup dan menunggu suhu meningkat sehingga Yosi B. Murti mereka dapat membelah diriDr.rer.nat. kembali

Freezing

Optimum temperature (0°C or lower) Tdk dapat diaplikasikan untuk obat, krn justru akan mempercepat rusaknya obat. Works by completely stopping enzyme activity & inhibiting spoilage microorganisms Bacteria Yeasts Molds


How long with frozen meat last?

Beef – 12 months

Lamb – 6-9 months

• Pork

- 6 months

Poultry – 3-6 months


Pengawetan dengan pemanasan

Pengaruh pemanasan, dengan meningkatnya suhu, sel-sel mikroba mati Dr.rer.nat. Yosi B. Murti semakin cepat hingga seluruhnya mati pada suhu diatas 80°C

Cooking

Works by heating products to high temperatures to kill microorganisms

2 types of cooking Pasteurization Sterilization


Sterilized Cooking

Bahan makanan dimasak dengan tekanan tinggi atau pemanasan 70 - 125ºC

All microorganisms killed

Products are shelf stable


Pasteurization

Louis pasteur for wine & beer, milk

Mild heating sufficient to kill micobes without seriously damaging the taste of the product

Thermoduric bacteria (heat resistance) survive


Pasteurization…. Cont.

Temp. 63ºC 30 min. Today : 72ºC 15 sec = High Temperature Short Time (HTST) pasteurization followed by refrigeration

Ultra High Temperature (UHT) without refrigeration milk in a thin film 74ºC through a chamber of superheated steam & reaches 140ºC & then cooled in a vacuum chamber 74ºC



Dehydration

Oldest forms of preserving meat

Works by removing water from the product water is required by all microorganisms to grow NO WATER = NO GROWTH

Dehydrate by air drying, heating, or freezing


Chemical

Chemicals inhibit microorganism growth

Examples Salt Sugar Chemical preservative : organic & anorganic


Chemical…. Cont.

Chemical preservative : organic : Sorbic acid, propionic acid, benzoic acid, asetic acid, epoxide Chemical preservative : anorganic : Sulfit, nitrit, nitrat


Chemical…. Cont.

Other benefits: Add flavor to the product Improve product shelf life Develop a pink cured-meat color

All Chemicals added to meat are FDA approved


Fermentation

Works by changing sugar into acid

Acid prevents microorganisms from growing

Tangy flavor and special texture developed

Example: “Pepperoni”


irradiation

A new process to make food SAFER!!!!

Works by exposing meat to radiant energy

Destroys most (but not all) microorganisms

“Radura” sign on labels


Irradiation…. Cont.

Reduces spoilage

Irradiated meat is still nutritious

Irradiated meat needs to be COOKED

IRRADIATED MEAT IS SAFE TO EAT!!!!


Radiation

1. Ionizing Radiation gamma

rays & x-rays, penetrates most substances Used on substances that could be damaged by heat plastic petri dishes, plastic syringes, catheters, surgical gloves Cause mutations in DNA and produce peroxides. Disadvantages: Penetrates human tissues. May cause genetic mutations in humans. Dr.rer.nat. Yosi B. Murti

Forms of Radiation


Radiation

2. Non-Ionizing Radiation UV Light, Wavelength is longer than 1 nanometer. Damages DNA by producing thymine dimers, which cause mutations. does not penetrate plastic, glass or proteinaceous matter

Used to reduce microbial populations

hospital rooms, nurseries, operating rooms

Disadvantages: Damages skin, eyes. Doesn’t penetrate paper, glass, and cloth.


Radiation 3. Microwave Radiation: Wavelength ranges from 1 millimeter to 1 meter. Heat is absorbed by water molecules. May kill vegetative cells in moist foods. Bacterial endospores, which do not contain water, are not damaged by microwave radiation. Solid foods are unevenly penetrated by microwaves. Trichinosis outbreaks have been associated with pork cooked in microwaves. Dr.rer.nat. Yosi B. Murti

Pasteurization

Disinfection - not sterilization (removes unwanted organisms)

Mycobacterium tuberculosis 63 C for 30 minutes 72 C for 15 seconds (HTST) Thermodurics

able

to survive high temps. Dr.rer.nat. Yosi B. Murti

Pengujian kontaminasi mikroba

Angka lempeng total Angka kapang / khamir total MPN (Most probably number) Uji mikroba patogen


Food & Drugs Preservation

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