Food Security.
 

Commercial reasons:

Extending the shelf-life,

Enhance product’s characteristics,

Create a new product,

◦ Recycling of meat, offal and other food sources. 

Food safety:
◦ Rawmaterials,
◦ Ingredients,
◦ Packaging,
◦ Growthofpathogenicbacteria,

◦ Shelf-life.

 Nutritional value,

 Healthy eating (e.g. fat and salt in the diet),

 Additives and colorants,
◦ Formation of toxic substances.

 Change in organoleptic properties.
 New technologies (e.g. radiation, UV light). 

Spoilage is the process in which food deteriorates to the point in which it is not edible to humans or its quality of edibility becomes reduced.

◦ Growth and activities of micro-organisms (bacteria, yeast and moulds),

• Activity of food enzymes,

• Chemical reactions in food,

• Inappropriate storage temperature for a given food,

• Infestation by parasites,

• Either excessive gain or loss on moisture,

• Reaction with oxygen,

• Light exposure,

• Physical stress,

• Time. 

Inactivating or controlling: ◦ Microorganisms,
◦ Enzymes.

 Reducing or eliminating chemical / physical reactions that cause food spoilage. 

Heat treatment of 90°C for 10 minutes, or a time and temperature combination sufficient to kill C. botulinum spores.

•   pH of 5 or less in all parts of the food.

•   Minimum salt level of 3.5% in the water phase

throughout all parts of the food.

 Water activity of 0.97 or less in all components of the food.

 Combination of the controlling factors can be used at lower levels or with other preservative factors, such as nitrite. 

Process Products results from the processing of: 

◦ Meat
◦ Raw milk

◦ Eggs
◦ Fishery

 Or from further processing of such processed products.

◦ Shelf-life,
◦ Colour and Odour,
◦ Consistency and Taste 

Products resulting from the processing of meat or from further processing of such processed products, so that the cut surface shows that the product no longer has the characteristics of fresh meat”.

To differentiate from:

◦ Minced meat,
◦ Meat preparations,
◦ Mechanically separated meat (MSM). 

FBO cannot use:

◦ Genital organs (except testicles),

◦ Urinary organs (except kidneys and bladder),

◦ Cartilage of the larynx, trachea and extra- lobular bronchi,

• Eye and eyelids,

• External auditory meatus,

• Horns,

◦ Poultry: head, oesophagus, crop, intestines, genital organs. 

Pasteurization
 Sterilisation
 Evaporation and distillation

 Extrusion
 Dehydration
 Baking and roasting
 Frying
 “Cook & Chill” 

Simple control of processing conditions,

•   No refrigeration required for storage,

•   Improves digestions of some

nutrients,

 Improves flavour, colour, taste and texture. 

Conduction: Transfer of heat from the heat source directly to the utensil.

 Convection: Heat transfer by convection requires the movement of air or liquids.

 Radiation: The transfer of heat by electromagnetic waves.

 Any combination of the above. 

Time - Temperature combination:

◦ Required to reach the core of any food and inactivate the most-heat resistant pathogens and spoilage bacteria,

◦ Difference with re-heating of food.

 Heat penetration characteristics in a

particular food:
◦ Size,
◦ Geometry,
◦ Moisture content,
◦ Can or container of choice, if it is packed. 

Direct effects on microorganisms: ◦ pH, fats and oils, starch, protein, sugar

(interfere with penetration of wet heat).

 Wet heat is more lethal than dry heat:

◦ Moisture is an effective conductor of heat and penetrates into microbial cells and spores. 

Denaturation of essential microbial proteins.

•   Ribosom denaturation.

•   Loss of osmotic function of microbial cell

membrane.

 Spores are more heat resistant due to their state of dehydration. 

Low order of heat treatment, generally at

temperature below 100oC,

◦ Leaves many bacteria viable,

◦ Designed to destroy most of pathogenic organisms (e.g. milk and liquid eggs, oysters),

◦ Limited storage life compared to commercially sterile products. 

Pasteurization (old method): 63oC for 30 minutes,

◦ Need cold storage
HTST = 72oC for 15 seconds (shelf life

up to 3 weeks) or 88oC for 1 second,

◦ Need cold storage

 UHT = 138oC for 2 to 5 second (shelf life up to 3-4 months). 

– complete destruction of all microorganisms:

◦ bacterial spores require at least 121oC wet heat for 15 min., 

– may contain small number of heat resistant bacterial spores (these will not normally multiply in the food supply).

◦ Most canned or bottled food products are commercially sterile and have a shelf life of 2 years or more. 

Foods are heated in their final containers:

◦ Commercial sterilization uses steam under pressure,

• Consider resistance of containers to pressure.

• See practical class notes on canned food.

 Foods are heated prior to packaging:

◦ Less damaging to food quality,

◦ Requires aseptic or nearly aseptic packaging conditions,

◦ Containers disinfected with hydrogen peroxide, heated air or UV light. 

Refrigeration and cold storage:
◦ Temperatures above freezing (7oC down to

-1oC),

◦ Commercial and household refrigerators (4.5 - 7oC).

 Freezing and frozen storage:

◦ Minimum freezing -12oC,
◦ Good freezing -18oC or below. 

Foods should be frozen at an internal temperature -18oC / shelf life.

 Microorganisms do not grow at -18oC, but some enzymes can still work (oxidation) and non-enzymatic reactions are not completely stopped. 

Most food spoilage microorganisms grow rapidly at temp ≥10oC.

 Some microorganisms are able to grow at temperatures as low as ≈ 0oC.

 Below -9.5oC there is no significant growth of spoilage or pathogenic microorganisms in food (there is a gradual decrease of the number of microorganisms).

 Freezing is not an efficient way to eliminate microorganisms. 

Air chilling is commonly used in the meat and poultry industries.

 Immediately after slaughter and dressing, carcasses are mechanically pulled or pushed into large insulated chilling rooms on connecting rails.

 When the chilling room is full, the doors are closed and the carcasses are chilled for a predetermined time. 

Cold refrigerated air is produced by evaporator coils positioned above the chill rooms. Within each coil, a low pressure liquid evaporates using heat extracted from the surrounding medium. The gas from this evaporator coil is then compressed and the high pressure gas, often referred to as “hot gas”, is passed through another coil referred to as a “condenser coil” where it condenses releasing heat. It then passes through an expansion valve back into the evaporator coil. In this system fans serve a dual function of pushing air over the evaporator coils and distributing the subsequently chilled air throughout the chill room. As the chilled air comes in contact with the surface of the carcasses the meat cools and the air increases in temperature. This warmed air is then returned to the evaporator coil to be re-chilled. 

Beef carcasses are typically chilled in air at 2°C to 4°C with an air velocity of less that 1 m/s and a relative humidity greater than 80% and are aged for 5-21 days. It takes around 24 hours for warm carcases (37°C) temperature to fall between 2°C to 4°C.



Chilled lamb carcases reach 2°C after 9 hours.

 Chilled pig carcases reach 2°C after 16 hours with Internal muscle temperature of 10°C at 12h and 2–4°C at 24h. 

Salmonella spp., Verocytotoxigenic Escherichia coli (VTEC), Listeria monocytogenes and Yersinia enterocolitica are the most relevant microbial pathogens when assessing the effects of beef, pork and lamb carcass chilling regimes on the potential risk to public health.

 Most bacterial contamination occurs on the surface of the carcass, the surface temperature is an appropriate indicator of bacterial growth.

 Key determinants of growth of microorganisms on meat are temperature, pH and aw, although other factors such as competition from other microorganisms might also be a factor. 

Minimum growth temperature of 5oC and an

optimum temperature of 35°C to 43°C,

 Growth at pH range of 4.5 to 9.0 and a minimum aw of 0.94.

 The observed Salmonella spp. prevalence on pig carcasses may decrease, remain unchanged or increase during chilling and subsequent chilled storage.

 This apparent inconsistency may be due to a range of factors including differences in chilling performance, bacterial strains, sampling methods, etc. but where a reduced prevalence was observed, this was attributed to the combined effects of cold shock and drying. 

Minimum growth temperature of 6-7oC, an optimum temperature of 35 to 42 °C,

 Growth between pH 4.4 and 10.0 and at a minimum aw of 0.95.



Inoculation studies with E. coli on beef carcasses stored at 10°C showed a 1.42 log reduction in the first 24 hours on the rump while growth was observed on the neck. This was attributed to the rapid decline in surface aw at the rump. In commercial chillers, E. coli counts on pig carcasses may remain unchanged or decrease during chilling, while E. coli counts on lamb carcasses decrease by up to 2 logs during the chilling phase. These reductions were also attributed to the drying of the carcasses. 

Ubiquitous in nature and in the abattoir environment.

 This organism grows optimally at 30 to 37 °C and although capable of growth at -1 °C, several studies have reported a reduction in Listeria on beef and pork carcasses during chilling.

 The pH range for growth is 4.4 to 9.4 and the minimum aw supporting growth is 0.92.

 Listeriosis in humans is not usually associated with fresh meat but with ready-to-eat products, in which contamination has occurred before or during processing, followed by growth during prolonged storage at refrigeration temperatures. 

The current legislation is based on a process criterion, temperature, and mandates that this must reach no more than 7°C throughout the carcass through a process of continuous chilling.



Adding a time parameter would deliver a time-temperature process criterion which would better define the chilling process.



There is no mathematical formula available to describe the relationship between core and surface temperature. 

Rapid or Ultra rapid – small ice crystals inside and outside the cells (-30 to -50oC for 12 to 18 hours),

 Slow – large ice crystals and clusters of crystals outside the cells (-8 to -20oC),

 Acceptable for most foods 1.3 cm/hour. 

Air freezing.

Freezing Methods

 Direct or indirect contact freezing – food or food package is in contact with a surface that is cooled by a refrigerant.

 Immersion freezing – direct contact of the food or package with the refrigerant:

◦ Submerging the food or spaying the cold liquid onto the food or package surface.

◦ Using freezing agents like liquid carbon dioxide or nitrogen. 

Air velocity.

 Thickness of product.

 Geometry of the system.

 Agitation degree of contact between food and cooling medium.

 Composition of the product.

 Resistance of heat transfer of the food package. 

Dark meat (Maillard reaction)

 Dry meat and Weight Loss
 Rancidity
 Moulds

 Costs associated with the Cold chain 

Very rapid thawing may have negative implication on quality:

◦ Meat exudation.
 If thawing is too slow bacteria can start

multiplying.

 Rapid thawing (15 to 20oC for 24 hours).

 Water (immersion or spray).

 Microwave (oven or tunnel). 

The thawing of foodstuffs is to be undertaken in such a way as to minimise the risk of growth of pathogenic microorganisms or the formation of toxins in the foods.

 During thawing, foods are to be subjected to temperatures that would not result in a risk to health.

 Where run-off liquid from the thawing process may present a risk to health it is to be adequately drained.

 Following thawing, food is to be handled in such a manner as to minimise the risk of growth of pathogenic microorganisms or the formation of toxins. 

Vacuum Packaging is the practice of extracting air from a packaging containing food before it is sealed.

 Modified Atmosphere is the practice of modifying the composition of the internal atmosphere of food packages in order to improve the shelf life of the product 

Vacuum Packing (VP) – oxygen-deficient environment:

◦ Primary transport and storage of large cuts of meat.  “Modified” Atmosphere Packaging (MAP):

◦ Gaseous environment around the product is modified before sealing.

◦ Gaseous environment changes during storage.
 “Controlled” Atmosphere Packaging (CAP):

◦ Gaseous environment more constant than in MAP, uses gas selective permeable materials (plastic aluminium foil laminates or metallised films)

 Nitrogen (N2) (reduce oxidation and aerobic bacteria). 

The optimum concentration ranges from 20-30%,

 The inhibition effect increases as:

◦ temperature decreases,

◦ pH decreases,

 Gram-negative bacteria are more susceptible to the inhibition effect than gram-positive,

 Carbon dioxide under pressure has a greater antimicrobial effect than carbon dioxide that is not under pressure. 

1. Vacuum pack

2. Hot water bath

• Not enough vacuum tight.

• Bone splinters or other foreign bodies.

• Seal not applied properly.

• Inappropriate plastic bags. 

Uses specially formulated top and bottom webs to create a vacuum skin consumer pack that fits around the product like a second skin 

The air in the chamber and package is evacuated, drawing the top web to the ceiling of the dome. The top web absorbs heat from the dome and becomes formable,

2. A gentle airflow is introduced and the top web relaxes and drapes itself gently over the product and the bottom web,

3. The dome opens and the top web shrinks skin-tight around all the product’s contours.

 The top and bottom films are heat-sealed to each other to form a completely flat seal right up to the edges of the product. 

Is any of various food preservation and flavouring processes, especially of meat or fish, by the addition of a combination of salt, nitrates, nitrite or sugar.

Changes:
◦ Preservation,
◦ Flavour - unique processed products, ◦ Colour,
◦ Tenderness. 

any substance, whether or not it has nutritive value, that is not normally consumed as a food in itself or used as a characteristic ingredient of food, and which, if added intentionally for a technological purpose to food in its manufacture, processing, preparation, treatment, packaging, transport or storage, results, or may reasonably be expected to result, in the substance or its by- products becoming directly or indirectly a component the food concerned”. 

Sodium chloride (Salt):
◦ Mild preservative and adds flavour, but

contributes to lipid oxidation,

◦ Improves yield and influences texture, protein extraction.

Nitrate (NO3) and nitrite (NO2):

◦ Meat flavour, preservative, anti-botulinum activity, fixes the red colour of cured meats, retards oxidative rancidity 

Chronic toxicity (e.g. nitrosamine)

 Allergic reactions (e.g. eggs, celery, etc.)

 "Chinese restaurant syndrome“ (monosodium glutamate syndrome)

- GI problems

•   Hyperactivity (e.g. some food colours)

•   Endocrine Active Substances (e.g. Biosphenol A)

◦ Substances that can interact or interfere with normal hormonal action. When this leads to adverse effects, they are called endocrine disruptors. 

Six food colours associated with possible hyperactivity in young children.

 The colours, identified by the Food Standards Agency, are:

◦ sunset yellow FCF (E110) ◦ quinoline yellow (E104)
◦ carmoisine (E122)
◦ allura red (E129)

◦ tartrazine (E102)
◦ ponceau 4R (E124) 

Dry salt:
◦ Dry salt (salt alone or in junction with nitrite and nitrate), ◦ Dry “country style” curing – salt, sugar, nitrate and nitrite, ◦ Brine soaking.

 Curing pickle injection:
◦ Artery pumping,
◦ Stitch pumping,
◦ Multiple needle injection curing.

 Any Combination of the above 

Dehydration.
 Remove oxygen from the product.

 Bacteria more sensitive to CO2.
 Depends on concentration. 

Nitrate (NO3)

 Nitrite (NO2)

Nitrate and Nitrite

 Nitrous Acid (HNO2)

•   Meat colour

•   Antimicrobial effect (especially on

Clostridium spp.)
 Limitations (nitrosamine, abnormal meat) 

It consists in exposing food products to smoke obtained from the incomplete combustion of different types of wood (beech, oak, juniper, chestnut).

 Herbs, spices, twigs of juniper and twigs, needles and cones of picea may be added if they are free of residues of intentional or unintentional chemical treatment.

 These fumes are rich in aromatic substances (phenol) which are of particular antiseptic power. 

Drying effect to meat, fish and dairy products

 Taste
 Pleasant odour
 Brings out the colour of the meat

 Antioxidant
 Antimicrobial 

From the combustion of lignin:
◦ Phenolic compounds (pyrogallol – cresol –

creosote – guaiacol, etc.). ◦ Tar



From the combustion of cellulose:
◦ Acids (acetic - butyric - caprylic - carbonic -

etc.).

• Ketones (acetone)

• Aldehydes (acetaldehyde - furfural) 

  
  

   

  Strong: enterobacteria spp, salmonella spp, bacillus subtilis;

   Poor: clostridia spp, yeast

  •   Acids = bactericidal / antiseptic

  •   Aldehydes = bactericidal / antiseptic

  •   Alcohols = secondary alcohols antiseptic

  •   Phenols = antioxidant action

  •   Phenols and ketones = Flavorings 

  
  

Polycyclic Aromatic Hydrocarbons:

◦ Benzo (a) pyrene
◦ Benzo (a) anthracene
◦ Dibenzo (a, h) anthracene ◦ Benzo (g, h, i) perylene
◦ Benzo (b) fluoranthene
◦ Benzo (k) fluoranthene
◦ Indeno (1,2,3-c-d) pyrene

 Mutagen agents: ◦ Formaldehyde

 Cancerogenic agents: ◦ Aldehydes 

Regulation (EC) No 2065/2003: on smoke flavourings used or intended for use in or on foods.

 Art. 4: The use of smoke flavourings in or on foods shall only be authorised if it is sufficiently demonstrated that:

◦ It does not present risks to human health,

◦ It does not mislead consumers. 

Advanced further then other alternative physical methods of food treatments,

 Emerged technologies for some applications:

◦ Ready-To-Eat meats and fresh juices.
 Commercially economical processes

became viable,

 Approved by some regulatory agencies (USA and Canada). 

Independent of product mass, size and geometry,

•   Minimise treatment time,

•   Inactivates vegetative cells, spores and

toxins,

 Destroys enzymes (peroxidases, xanthine oxidase, amino acids oxidase),

 Minimal impact on quality and nutrition. 

 Pascal's principle:

◦ "A pressure exerted on an incompressible liquid is evenly distributed in all directions and with the same intensity at all points of the liquid (isostatic pressure) and also on the surface of a body (food) immersed in the liquid“.

 Compression raises temperature of the product to 2- 8°C per 100 MPa (<600MPa pasturization effect, >700MPa sterilization effect),

◦ Target of microorganisms,

◦ Product selection and formulation, including choice of packaging. 

Normally: Spore > gram (+) > gram (-),

 Heat-resistant bacteria are usually more pressure-resistant than heat sensitive types,

 Pressure resistance often reaches a maximum at ambient temperatures

 Initial temperature of the food prior to HHP can be reduced or elevated to improve inactivation at processing temperature 

Anisakis simplex larvae are killed by treatments employing pressures of 200MPa for 10 minutes at 0°-15°C

 Trichinella spiralis is inactivated by pressures above 175MPa for 10 minutes at 25°C. 

USA:

◦ USDA has approved HHP as an intervention method for Listeria contaminated pre-packed RTE meat products,

◦ FDA has accepted the commercial use of pressure-assisted thermal sterilization (PATS) processes for application in the production of low acid foods (LAF).

 Health Canada – Novel Foods Decisions:

◦ Use of HHP for processing RTE Meat Products. 

Well developed for water and air treatment since 1930,

 Viable option for non-food contact and food surface treatment,

 Viable non-thermal alternative for liquid foods preservation,

 Physical method - no chemicals,

 Cost effective and energy efficient,

 Approved by some Regulatory Agencies. 

To reduce levels of pathogens (Listeria and Salmonella) on meats, poultry and fish,

 Salmonella in Shell-eggs,

 Extended Shelf-life bakery products,

 Food powders (black pepper and wheat flour). 

UV light doesn’t penetrate opaque substances:

- surface shielding effects 

High doses of UV can cause unwanted effects furan formation in sugar solution (fructose and glucose),

Changes in the nutritional value,

May affect quality appearance of foods. 

In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space.

 There are two distinct types of radiation; “ionising” and “non-ionising”.

 The word radiation is commonly used in reference to ionising radiation only (i.e., having sufficient energy to ionise an atom). 

Ionising Radiation:
◦ X-rays or gamma rays,

 Electromagnetic “non- ionising” radiation:

◦ Microwaves

◦ UV-Rays 

means any gamma rays, X-rays or corpuscular radiations which are capable of producing ions either directly or indirectly; 

are used in food preservation because they don’t produce «secondary» radiation in products of animal origin. 

Intrinsic (food contaminated at source):

◦ Radio-isotopes are normally present in nature (radium, caesium, cobalt, plutonium, polonium, etc...),

◦ As a consequence of a natural disaster (Earthquake in Fukushima Japan, 2011).

◦ As a consequence of human-made disaster (Chernobyl in Ukraine, 1986).

 Extrinsic (radiation applied to food during processing). 

Advantages:
◦ Little or no heating of food with negligible

change to sensory characteristic,

• Packaged or frozen foods can be treated,

• No chemical preservatives needed,

• Very low energy requirement,

• Low operating cost. 

These than further reacts to cause changes in irradiated material known as radiolysis. It is this reaction that cause the destruction of micro-organisms. Insects and parasites during food irradiation.



Particularly effective in foods with high moisture content.

Radiation and Microorganisms

◦

Radiolysis: Formation of hydrogen, hydrogen peroxide, hydrogen radicals (H-), etc..)

 Smaller and simpler organisms are more resistant to radiation. 

are commonly used for the decontamination of minced meat (X-rays) and poultry meat (since 1990).

 The maximum recommended dose for food is 15kGy, with the average dose not exceeding 10kGy (WHO, 1977, 1984, 1994).

 Packaging material and food can be easily altered by radiations (carcinogenic agents). 

Fruits(max2kGy);

◦ Vegetables (max 1kGy);

◦ Cereals (max 1kGy);

◦ Bulbs and tubers (max 0.2kGy);

◦ Dried aromatic herbs, spices and vegetable seasonings (max 10kGy);

◦ Fish and Shellfish (max 3kGy); ◦ Poultry (max 7kGy);