Food Preservation Note PDF

Food preservation note Overview view of food preservation Introduction What’s food?  Foods are materials, raw, processed, or formulated, that are consumed orally by humans or animals for growth, health, satisfaction, pleasure, and satisfying social needs.  foods are for the most par...

Food preservation note Overview view of food preservation Introduction What’s food?  Foods are materials, raw, processed, or formulated, that are consumed orally by humans or animals for growth, health, satisfaction, pleasure, and satisfying social needs.  foods are for the most part composed of edible biochemical Discuss food preservation and processing? Explain the need for food preservation? Explain different conventional food preservation methods?  Chemically food are mainly composed of  Water  Lipid  Fat  Carbohydrate  Minerals & Organic Compound In Small Proportion  There is evidence in recorded history dating back to 3000 years B.C. about converting the harvest surplus of  Grape Into Wine And  Preserving Milk By Making Yoghurt, Cottage Cheese, Butter And Ghee.  Preservation by sun-drying of fruits, vegetables, meats, etc.; is older than recorded history and was prevalent even before the discovery of fire by man.  Most of the preservation techniques practiced by the early humans were based on daily experiences.   Utilization of natural energy  Including Solar, Biomass, And  Natural Phenomena Such As Evaporation, Cooling, spontaneous reactions like fermentation are some of the common features of these food preservation techniques. Food processing:  Food processing is the set of methods and techniques used to transform raw ingredients into food for consumption by humans or animals.  Food processing often takes  clean,  harvested or slaughtered and  Components convert into attractive and marketable food products. HISTORY OF FOOD PRESERVATION TECHNIQUES chemical preservation(1950+ canning (1809 refregeretion (1784 smoking (3500BC salting and curing (3600BC fermentation (10000BC drying 12000BC cooking 50000BC Food preservation:-  Food preservation is the process of treating and handling food in such a way as to stop or greatly slow down its spoilage and to prevent food borne illness while maintaining the food item’s nutritional value, texture and flavor.  Preservation methods start with the complete analysis and understanding of the  whole food chain, including growing, o harvesting, o processing, o packaging, and  o distribution; thus an integrated approach needs to be applied First, it is important to identify the properties or characteristics that need to be preserve why preservation.  The main reasons for food preservation are  to overcome inappropriate planning in agriculture,  produce value-added products, and  provide variation in diet  Value-added food products can give better quality foods in terms of improved nutritional, functional, convenience, and sensory properties.  In food preservation, the important points that need to be considered are: the desired level of quality, the preservation length, and the group for whom the products are preserved. importance of food preservation Prevents the growth of pathogenic microorganisms and the occurrence of foodborne illnesses; helps in retaining taste, texture, color, and nutritional value; extends the shelf life of perishable foods, minimizing food waste; and increases the availability and affordability of food products throughout the year. factors influencing food preservation :- Food type (different foods require specific preservation methods based on their composition); storage conditions (temperature, humidity, and light exposure can greatly influence the effectiveness of preservation techniques); and  consumer preferences (flavor, texture, and nutritional attributes can dictate the choice of preservation method).  Quality is an elusive, ever-changing concept. In general, it is defined as the degree of fitness for use or the condition indicated by the satisfaction level of consumers.  The product quality attributes can be quite varied, such as  appearance,  sensory, or  microbial characteristics.  Loss of quality is highly dependent on a. types of food and composition, b. formulation (for manufactured foods), c. packaging, and storage conditions HOW LONG TO PRESERVE?  Best before date is set shorter than the shelf life with a good margin  Products may be marketed with the  production date  “pack date” and “  best-before date.” Alternative markings are use-by date or expiration date, which may be closer to shelf life than best before date. quality can be defined using many factors, including appearance, yield, eating characteristics, and microbial characteristics, but ultimately the final use must provide a pleasurable experience for the consumer.  Quality loss can be minimized at any stage and thus quality depends on the overall control of the processing chain. FOR WHOM TO PRESERVE  Food poisoning can be fatal,  especially in infants,  pregnant women,  the elderly, and those with depressed immune systems. Figure 2 Various stages of food production, manufacture, storage, distribution, and sale. COUSE OF FOOD DETERIORATION  Mechanical,  physical,  chemical, and  microbial effects are the leading causes of food deterioration and spoilage. Other examples of deterioration can be listed as follows: 1. bruising of fruits and vegetables during harvesting and postharvest handing, leading to the development of rot, 2. tuberous and leafy vegetables lose water when kept in atmospheres with low humidity and, subsequently, wilt, and 3. dried foods kept in high humidity may pick up moisture and become soggy.  The four sources of microbial contaminants are  soil,  water,  air, and   animals (insects, rodents, and humans) Figure 3 Factors affecting food quality, safety, and choice.   During storage and distribution, foods are exposed to a wide range of environmental conditions.  Environmental factors such as pressure, temperature, humidity, oxygen, and light can trigger several reactions that may lead to food degradation. MECHANISMS OF FOOD SPOILAGE Bacteria, yeasts, and molds can cause spoilage and foodborne diseases;  natural enzymes in food can lead to spoilage processes such as browning and nutrient degradation;  exposure to oxygen can cause rancidity and loss of flavor; and environmental conditions like temperature and humidity can impact food stability and quality. Each microorganism has an optimum temperature at which it grows best, a minimum temperature below which growth no longer takes place, and a maximum temperature above which all development is suppressed. Bacteria that grow particularly well at low temperatures are called:- psychrophilic (cryophilic) or low-temperature organisms. Bacteria with an optimum temperature of 20°C–45°C are mesophilic, and those with an optimum temperature above 45°C are thermophilic.  Many enzymatic reactions change the quality of foods. For example, fruits when cut tend to brown rapidly at room temperature due to the reaction of phenolase with cell constituents released in the presence of oxygen. . Enzymes such as lipooxygenase, if not denatured during the blanching process, can influence food quality even at subfreezing temperatures.   In addition to temperature, other environmental factors such as oxygen, water, and pH induce deleterious changes in foods that are catalyzed by enzymes.  The presence of unsaturated fatty acids in foods is a prime reason for the development of rancidity during storage as long as oxygen is available.  While development of off-flavors is markedly noticeable in rancid foods, the generation of free radicals during the autocatalytic process leads to other undesirable reactions, for example, loss of vitamins, alteration of color, and degradation of proteins.  The presence of oxygen in the immediate vicinity of food leads to increased rates of oxidation. Similarly, water plays an important role; lipid oxidation occurs at high rates at very low water activities  Some chemical reactions are induced by light, such as loss of vitamins and browning of meats.  Nonenzymatic browning is a major cause of quality change and degradation of the nutritional content of many foods. This type of browning reaction occurs due to the interaction between reducing sugars and amino acids, resulting in the loss of protein solubility,  darkening of lightly colored dried products, and development of bitter flavors. Environmental factors such as temperature, water activity, and pH have an influence on nonenzymatic browning. FOOD PRESERVATION METHODS  The methods of preservation depend on the origin of foods—particularly whether they are of plant or animal origin Based on the mode of action, the major food preservation techniques can be categorized as  slowing down or inhibiting chemical deterioration and microbial growth,  directly inactivating bacteria, yeasts, molds, or enzymes, and  Avoiding recontamination before and after processing.  Postharvest handling of foods of plant origin includes efficient control of environmental atmosphere, such as  humidity,  gas composition, and  temperature, and  Implementing an adequate packing, storage, and transport system.  Physical treatments usually used are curing, precooling, temperature treatments, cleaning, and waxing, whereas  chemical treatments are disinfection, fumigation, and dipping.  Meat is the edible flesh of a number of species of mammal or bird, both wild and domesticated. Postharvest quality is affected by slaughter conditions or stress before death.  In the case of fish, preservation methods include chilling, electrical stimulation, and decontamination methods,  for example, hot water rinsing with or without chlorination, decontamination with o phosphate, o hydrogen peroxide, o chlorine, o chlorine dioxide and ozone, and  o Surface treatment by organic acids. o Pretreatments, such as blanching, sulfiting, and Other physical and chemical pretreatments are used before applying major preservations methods.  The main purpose of pretreatment is to improve product quality and process efficiency.  Chemical disinfectants vary in their ability to kill microorganisms.  Effectiveness depends on the types of microorganisms, their attachment mechanisms, and Physical characteristics of the produce.  Some disinfectants are appropriate for use in direct-contact washes; others only for processing water, processing equipment or containers and facilities.  Several chemicals are utilized, such as chlorine, chlorine dioxide, hydrogen peroxide, ozone, peroxyacetic acid, bromine, iodine, trisodium phosphate, and quaternary ammonium compounds.  Although fumigants are not strictly preservatives, they are used for insect control.   Methyl bromide is one of the fumigants used, but it has the potential to damage atmospheric ozone and is being phased out. There is a need for development of new environmentally safe methods of fumigation. Figure 3 Major food preservation techniques. METHODS OF FOOD PRESERVATION  Traditional preservation methods o Canning o drying{air drying,sundrying, freeze drying} o salting and brining  o fermentation o smoking  modern preservation technologies:- Refrigeration and freezing High-pressure processing (HPP) Pasteurization Irradiation Modified atmosphere packaging (MAP)  Emerging preservation techniques nano technology active packaging biopreservation UNIT 2 Principle And Application Of Hurdle Technology Introduction What is novel food means? What’s the term hurdle technology indicate in food technology? The hurdle effect is of fundamental importance for the preservation of foods, since the hurdles in a stable product control  microbial spoilage,  food poisoning, as well as  desired fermentation processes.  In industrialized countries, hurdle technology is currently of particular interest for Minimal-processed, convenience foods, whereas   In developing countries foods storable without refrigeration, due to stabilization by hurdle technology, are at present of paramount importance.  The hurdle technology concept proved successful, as an intelligent combination of hurdles secures microbial stability and safety as well as the sensory quality of foods, it provides convenient and healthy foods to the consumer, and is cost-effective for producers since it demands less energy during production and storage. Principles of Food Preservation  Many preservation methods are used for making foods stable and safe, e.g., heating, chilling, freezing, freeze drying, drying, curing, salting, sugar addition, acidification, fermentation, smoking, and Oxygen removal.  however these process are based on few parameters or hurdles e.g o F VALUE(high T; Heating o T VALUE (low T;chilling,freezing o aW(water activity; drying, salting,sugaring,freezing o pH( acidity; acidification o Eh( REDOX potential;oxygen removal, ascorbate addition ) o Pres( preservatives;sulfite,sorbate,nitrite o C.f( compititive flora : fermentation  novel non-thermal preservation methods(secondary hurdles) e.g o high hydrostatic pressure o mano-thermo-sonication  o osillating magnetic field and o light pulses  the heat resistance of bacteria Increases at low aw and decreases at low pH and in the presence of some preservatives, whereas a low Eh increases the inhibition of microorganisms caused by a reduced aw. HURDLE TECHNOLOGY  The hurdle effect is, for instance, important for the ultraclean or aseptic packaging of foods, because if there are only few microorganisms present at the start, then a few or low hurdles are sufficient for the stability of the product.  The same proves true if the initial microbial load of a food (e.g., on carcass meat or on high-moisture fruits) is substantially reduced (e.g., by the application of steam), because after such decontamination procedures fewer microorganisms are present, which are then more easily inhibited.  Using an intelligent mix of hurdles, it is possible to improve not only the microbial stability and safety, but also the sensory and nutritive qualities, as well as the economic aspects, of a food. Fundamentals of hurdle technology: Food preservation implies exposing microorganisms to a Hostile environment to inhibit their growth, shorten their survival, or cause their death   Advances have been made by considering the  homeostasis,  metabolic exhaustion, and  Stress reactions of microorganisms, as well as by introducing the concept of multi target preservation for gentle yet effective preservation of foods. Homeostasis: Homeostasis is the tendency In food preservation, the homeostasis of microorganisms is a key phenomenon, which deserves much attention, because  if the homeostasis of these microorganisms is disturbed by preservative factors (hurdles) in foods, they will not multiply, i.e., they remain in the lag phase or even die, before homeostasis is repaired (reestablished).  Food preservation is achieved by disturbing the homeostasis of microorganisms in a food temporarily or permanently. A wide range of mechanisms (e.g., osmoregulation to counterbalance a hostile water activity in food) have developed in microorganisms that act to keep important physiological systems operating, and unperturbed even when the environment around them is greatly perturbed. Metabolic exhaustion: Owing to autosterilization, hurdle-technology foods, which are microbiologically stable, become safer during storage, especially at ambient temperatures. For example, salmonellae that survive the ripening process in fermented sausages will vanish more quickly if the products are stored at ambient temperature, and they will survive longer and possibly cause foodborne illness if the products are stored under refrigeration. It is also well known that salmonellae survive in mayonnaise at chill temperatures much better than at ambient temperatures.  metabolic exhaustion is accelerated if more hurdles are present, and this might be caused by increasing energy demands to maintain internal homeostasis under stress conditions. Thus, it could be concluded that refrigeration is not always beneficial for the microbial safety and stability of foods. However, this is only true if the hurdles present in a food inhibit the growth of microorganisms also without refrigeration, if this is not the case then refrigeration is beneficial. Certainly, the survival of microorganismsin stable hurdle-technology foods is much shorter without refrigeration. Stress reactions: Some bacteria become more resistant or even more virulent under stress, since they generate stress shock proteins. The synthesis of protective stress shock proteins is induced by heat, pH, aw, ethanol, oxidative compound, as well as by starvation. Stress reactions might have a nonspecific effect, since due to a particular stress microorganism become more tolerant to other stresses, i.e., they acquire a “cross-tolerance.” Multitarget preservation: Recent applications of hurdle technology Provisions for the army: Hazard Analysis Critical Control Point (HACCP):- Fusion foods of china: The Chinese fusion meats are called retort sausages or ham sausages, they are emulsion-type products to which 5%–10% starch, 3%–5% soy protein, 0.3%0.5% carrageen, and 0.3%–0.5% polyphosphates are added, and they are heated at retort temperatures of 115°C–120°C for 20–30 min to achieve a shelf life at ambient temperatures for at least 6 months. Novel fruit preservation: The main goal was to preserve fruits in fresh-like condition even if stored for several months without refrigeration, Five hurdles for the preservation of high moisture fruit products (HMFP): (1) mild heat treatment (to inactivate enzymes and lower the initial microbial load); (2) slight reduction of aw (by addition of sucrose or glucose); (3) pH adjustment if necessary (by addition of citric or phosphoric acid (4) addition of preservative I (potassium sorbate or sodium benzoate (5) addition of preservative II (sodium sulfite or bisulfite) in moderate amounts. This process results in stable and safe fresh-like products storable for at least 3–8 months (i.e., from one harvest peak to the next) at ambient temperatures by using modest packaging Design of hurdle-technology foods These three concepts have related but different goals: hurdle technology is primarily used in food design, predictive microbiology for process refinement, and HACCP for process control. Steps of food design: 1. the desired sensory properties and the desired shelf life are tentatively defined. 2. A feasible technology for the production of this food must be outlined. 3. the resulting product is analyzed for pH, aw, preservatives, and other inhibitory factors. Temperature for heating (if intended) and storage as well as the expected shelf life are defined. 4. For testing the preliminary microbial stability of the food product, predictive microbiology might be employed. 5. The product is challenged with toxigenic and spoilage microorganisms using somewhat higher inocula and storage temperatures than would be “normal” for this food. 6. If necessary, the hurdles in the products are modified, taking multitarget preservation and the sensory quality of the food (i.e., total quality) into consideration. 7. The food is again challenged with relevant microorganisms and, if necessary, the hurdles in the food are modified again. Predictive microbiology for assessing the safety of the food might be helpful at this stage too. 8. After the established hurdles of the modified or novel foods are exactly defined, including tolerances, the methods for monitoring the process are agreed upon. Preferably, physical methods should be used for monitoring. 9. The designed food should now be produced under industrial conditions, because the possibilities for a scale-up of the proposed manufacturing process must be validated. 10. For the industrial process the critical control points (CCPs) and their monitoring must be established, and therefore the manufacturing process should be controlled by HACCP. If HACCP is not appropriate, guidelines for the application of manufacturing control by good manufacturing practice (GMP) must be defined