Table of Contents
Q.1. Discuss the various factors affecting the growth of microorganisms along with the Growth Curve.
Factors Affecting Growth Of Microorganisms
1. TEMPERATURE
Microorganisms have optimum growth temperature .They do not grow above or below a specific range of temperature. Bacteria can grow and survive under more extreme conditions than those tolerated by any of the molds or yeasts. Bacteria’s are classified as:-
Psychrophiles – 68 °-77 °F (45 °F) (0-20 °C)
Mesophiles – 98 °F (20 °-45 °C)
Thermophiles – 110 °F (45 °-60 °C)
Moulds can grow and can survive under more extreme conditions than can the yeasts.
2. WATER
3. pH (hydrogen ion concentration)
Moulds, yeast grow best at PH on the acidic side of neutrality as do some bacteria. Many species of bacteria grow at PH which are at neutrality or slightly on alkaline side. Extreme PH for bacteria (PH 4 – PH 11)
4. NUTRITIONAL REQUIREMENTS OF MICROBES
Microorganisms especially bacteria vary greatly from species to species. In the presence of some inorganic salts some bacteria can utilize the nitrogen in air to form proteins and carbon dioxide in air to obtain energy they also use lactates as source of energy. Moulds and yeast like bacteria require basic elements – carbon, hydrogen, nitrogen, phosphorus, sodium, sulphur etc. as well as vitamins & other organic compounds.
5. OXYGEN REQUIREMENT
Some bacteria are aerobic that is they require oxygen for growth. Some both presence and absence (facultative aerobes/anaerobes) bacteria that do not require oxygen – anaerobes. Moulds & yeast require.
The curve is divided into phase as indicated in the fig:
(1) The initial lag phase (A to B), during which there is no growth or even a decline in numbers.
(2)The phase of positive acceleration the rate of growth is continuously increasing. (3)The log or exponential phase of growth (C to D), during which the rate of multiplication is most rapid and is constant.
(4)The phase of negative acceleration (D to E), during which the rate of multiplication is decreasing.
(5)The maximal stationary phase (E to F), where numbers remain constant.
(6)The accelerated death phase (F to G)
.
(7)The death phase or phase of decline (G to H), during which numbers decrease at a faster rates then new cells are formed and
(8)The survival phase (H to I) during which no cell division occur but remaining cells survive on endogenous nutrients.
Q.2. Explain the principles of HACCP and discuss its importance in food sector.
The Seven HACCP Principles
Principle 1: Conduct hazard analysis.
Plants determine the food safety hazards identify the preventive measures the plant can apply to control these hazards.
Principle 2: Identify critical control points.
A critical control point (CCP) is a point, step, or procedure in a food process at which control can be applied and, as a result, a food safety hazard can be prevented, eliminated, or reduced to an acceptable level. A food safety hazard is any biological, chemical, or physical property that may cause a food to be unsafe for human consumption.
Principle 3: Establish critical limits for each critical control point.
A critical limit is the maximum or minimum value to which a physical, biological, or chemical hazard must be controlled at a critical control point to prevent, eliminate, or reduce to an acceptable level.
Principle 4: Develop critical control point monitoring procedure
Monitoring activities are necessary to ensure that the process is under control at each critical control point. FSIS is requiring that each monitoring procedure and its frequency be listed in the HACCP plan.
Principle 5: Create protocols for critical control point deviations
These are actions to be taken when monitoring indicates a deviation from an established critical limit. The final rule requires a plant’s HACCP plan to identify the corrective actions to be taken if a critical limit is not met. Corrective actions are intended to ensure that no product injurious to health or otherwise adulterated as a result of the deviation enters commerce.
Principle 6: Ensure correct record keeping and documentation
The HACCP regulation requires that all plants maintain certain documents, including its hazard analysis and written HACCP plan, and records documenting the monitoring of critical control points, critical limits, verification activities, and the handling of processing deviations.
Principle 7: Verify effectiveness of the HACCP system
Validation ensures that the plans do what they were designed to do; that is, they are successful in ensuring the production of safe product. Plants will be required to validate their own HACCP plans. FSIS will not approve HACCP plans in advance, but will review them for conformance with the final rule.
Verification ensures the HACCP plan is adequate, that is, working as intended. Verification procedures may include such activities as review of HACCP plans, CCP records, critical limits and microbial sampling and analysis. FSIS is requiring that the HACCP plan include verification tasks to be performed by plant personnel. Verification tasks would also be performed by FSIS inspectors. Both FSIS and industry will undertake microbial testing as one of several verification activities. the occurrence of the identified food safety hazard.
HACCP is extreme importance because it prioritizes and controls potential hazards in food production. By controlling major food risks, such as microbiological, chemical and physical contaminants, the industry can better assure consumers that its products are as safe as good science and technology allows.
Q.3. What is Food Contamination and its various sources? Discuss in detail.
Food contamination refers to the presence in food of harmful chemicals and microorganisms which can cause consumer illness. Various sources of food contamination are as follows:
Plants- Though the number of microbes in the interior of plant foods is nil or very small, sometimes, coli forms. Pseudomonas, lactobacillus, yeast are found in the inner tissue of healthy fruits
Animals- The surface flora, and more importantly, the flora of the respiratory tract and intestinal tract are the sources of microbial contamination. The hides, hooves and hair of animals, and feet and feather of birds are loaded with undesirable organisms. They also release microbes through excretion and secretions. On slaughtering, the microbes from the skin and respiratory tract get transmitted to the carcass and product
Sewage- On being used untreated as a fertilizer in food crops.
Soil- Different types of moulds, yeasts and bacteria are found in soil. Washing and cleaning are processes that remove soil from the surface of the plant
Water- Natural flora in addition to contaminants in the form of microbes form soil, animals and sewage. Surface stored water has more microbes as compared to underground water
Air- Microbes don’t grow in the air, they merely exist there. The ones which can survive in low moisture, live the longest. Micorbes adhere to soil particles in the air or in the moisture droplets. Air currents increase the number of microorganisms while dryness reduces them.
Handling and processing- Food may get contaminated during handling and processing through the equipment, the packaging material and personnel. Such contamination can be minimized by santising the equipments and using adequate packaging materials and maintaining hygiene.
OR Discuss the various methods of food preservation in detail.
Food preservation is the process of treating and handling food to stop or slow down food spoilage, loss of quality, edibility, or nutritional value and thus allow for longer food storage Various methods of food preservation are as follows:
Asepsis
The principle of asepsis works on preventing the entry of disease causing and spoilage organisms.
Aseptic packaging
Aseptic processing
Use of high temperature
Heating extends the shelf life of food by killing microorganisms through denaturation od proteins and inactivation of enzymes
Blanching– Pretreatment usually carried out in vegetables prior to dehydration, freezing or canning to inactivate the enzymes. The vegetables are dipped in boiling water for 1-5 minutes.
Pasteurization- It is a mild heat treatment which is carried out at a temperature below 100°c followed by immediate cooling to kill the undesirable microorganisms. Important for processing milk.
Sterlization- Severe heat treatment at a temperature of 121°c which results in complete destruction of microorganisms and also alters the organoleptic and nutritive quality of food adversely.
Use of low temperature
The underlying principle of low temperature preservation is that it decreases the rate of chemical and enzymatic reactions and controls the replication and propagation of microorganisms
Refrigeration- Doesn’t destroy microbes, but slows down their enzymatic activity and prevents their replication, thereby delaying spoilage
Freezing- preserves by converting water into ice and making it unavailable for microbial and enzymatic growth
Removal of moisture
Possibly the oldest method of food preservation practiced by man.
Sun drying- Slow process limited to hot and dry climate and is suitable for a few fruits Dehydration- Complete removal of moisture from food under controlled conditions of temperature , humidity and air velocity in dehydrators. Drying preserves food, prolongs its shelf life, decreases itl bulk, and weight as well as the transportation and packaging costs.
Concentration- Employed for liquid foods. Concentration decreases the moisture content by 20%
Use of preservatives
They are food additives which are intentionally added to inhibit, retard or arrest the growth of microorganisms and thereby preventing fermentation, acidification or other decomposition of food.
Class I preservatives- Safe for human consumption and can be added to any amount to food. Eg: sugar, salt, spices, vinegar etc.
Class II preservatives- Chemicals used within prescribed limits. Eg: benzoic acid, sulphites, nitrates etc.
Modification of pH
Microbe growth is inhibited if pH is changed from its ideal level and increased or decreased.
Adding organic acids
Fermentation
Irradiation
Works on the principle that ionizing radiations interact with food material by transferring energy to the electrons and ionizing molecules by creating positive and negative charge. Different methods are Radurization Radicidation Radapperrtization
Q.4. (a) Explain the following terms:
(i) GAP
Good Agricultural Practices (GAPs) are ways that produce growers can prevent on-farm contamination of fruits and vegetables. GAPs are a new way of thinking about food safety.
(ii) GMP
Good Manufacturing Practice (GMP) is a system for ensuring that products are consistently produced and controlled according to quality standards. It is designed to minimize the risks involved in any pharmaceutical production that cannot be eliminated through testing the final product.
(iii) PFA
Prevention of Food Adulteration Act was promulgates in 1954 for preventing adulteration of food. It is a mandatory law which covers both primary and processed foods. It aims at protecting the consumer from food that are impure, not safe, or falsely labeled..
(iv) WHO
World Health Organization is a specialized agency of the United Nations that is concerned with international public health. It has a mission to assist member states to strengthen their programs for improving food safety along the entire food production chain from production to consumption.
(v) FPO
The FPO mark is a certification mark mandatory on all processed fruit products sold in India such as packaged fruit beverages, fruit-jams, crushes and squashes, pickles, dehydrated fruit products, and fruit extracts, following the Food Safety and Standards Act of 2006. The FPO mark guarantees that the product was manufactured in a hygienic ‘food-safe’ environment, thus ensuring that the product is fit for consumption
(b) Differentiate between Food Additives and Adulterants. Give examples of each.
Additive- Food additives are substances added to food to preserve flavor or enhance its taste, appearance, or other qualities.
Adultrant- An adulterant is a pejorative term for a substance found within other food substances even though it is not allowed for legal or other reasons.
Additive- Can be nutritionally beneficial
Adultrant- Never nutritionally beneficial
Additive- Improves quality
Adultrant- Deteriorates quality
Additive- improves shelf life and functional property
Adultrant- No effect on shelf life and functional property of food
Additive eg: Pectin in jams, Baking soda in cookies, Aspartame to diet soda etc
Adultrant eg: Metanil yellow in turmeric, vanaspati in ghee, melanin in milk etc
Q.5. Discuss food packaging along with classifying packaging materials.
Packaging is the process, art, or style of packaging. The process of packing and the package itself influence the quality and safety of food products. In recent years, residues from packaging materials have created new problems of food contamination.
Packaging performs the following purposes:
- Physical protection
- Barrier
- Containment
- Convenience
- Portion control
- Marketing
- Security
A wide variety of packaging materials are used by the food industry. They can be grouped as follows:
Flexible
- Paper (laminated/waxed)
- Think plastic films
- Edible films/coating
Semi rigid
- Aluminium foils
- Paper boards
- Formed plastics
Rigid
- Glass
- Metal
- Thick plastics
Some of the latest innovations in the field of packaging include the following:
- Polymer based packing
- Protein and starch based edible films
- Self heating and self cooling packages
- Thermo chromic labelling
OR Discuss the role of codex alimentarius and WHO in food industry.
FAO & WHO jointly established the food standard programme & adopted the status of the CAC. The body responsible for completing the standards, code of practice, guideline & recommendations that constitute the Codex Alimentarius. This is an international food code. It creates standards that protect consumer, ensuring fair practices in the sale of food &trade, food control administration & traders.
It is a combine set of standards, codes or practices and other model regulations available for countries to use and apply to food industry in international trade. The dual objective of CODEX Alimentarius commission is to protect the health of consumers to facilitate international trade. CODEX commodity standards cover food as fruit juices cereals meat products etc. general standard cover areas applicable to most food hygiene and technological aspects such as food hygiene and technological practices. They are used by processor to insure that foods are microbiologically safe and are fit for human consumption. Maximum residue limits (MRLS) have been setup for pesticides specification for food grade quality of additives form an important part of CODEX work.
WHO – World Health Organization – It is established on 7th April 1948.To set the objectives of highest positive level of health. The main functions are as follows:
- Articulating ethical & evidence based policy.
- Managing information by assessing trends & comparing performances related to development.
- Changes through technical & policy support
- Negotiating & sustaining national & global partnership.
- Monitoring the validity on proper purchase & standard.
- Development new technology, tools & guide lines in health care management.
Its 5 key principles of food hygiene, are:
1. Prevent contaminating food with pathogens spreading from people, pets, and pests.
2. Separate raw and cooked foods to prevent contaminating the cooked foods.
3. Cook foods for the appropriate length of time and at the appropriate temperature to kill pathogens.
4. Store food at the proper temperature.
5. Do use safe water and cooked materials.