Cold Chain Management Cheatshe

Cheatsheet Content

### Introduction to Cold Chain Management **What is Cold Chain?** Involves the transportation and storage of temperature-sensitive products within their optimal temperature range along the supply chain. **What is Cold Chain Management?** A quality management system for transportation, storage, and logistical planning to protect the integrity of temperature-sensitive products. It ensures products are stored and transported within an uninterrupted flow of a specific temperature profile. **Quality Management Elements:** - **Science:** Understanding chemical and biological processes linked with perishability. - **Technology:** Physical means to ensure appropriate temperature conditions. - **Process:** Series of tasks to prepare, store, transport, and monitor temperature-sensitive products. ### Importance of Cold Chain Management 1. **Lowers Business Costs:** * **Reduces spoilage:** Minimizes product loss. * **Lower Customer Acquisition Cost:** Through better service and retention. * **Eliminates/Minimizes Crisis Management Cost:** Reduces product spoilage, loss of reputation, and potential legal liability. 2. **Growing Perishable Markets:** * **Growing affluence:** Demand for fresher, safer, and better quality perishable foods. * **Greater food safety awareness:** Accreditation builds customer confidence. 3. **Extends Shelf Life of Products:** * Reduces product loss and saves time/cost on managing returns. **Key Drivers of Food Loss:** - Poor disease and pest management - Over-importation of food items - Fragmented cold chain management - Inadequate infrastructure ### Introduction to Perishables **What are Perishables?** Products whose quality deteriorates over time due to environmental conditions. - **Examples:** Food products (meat, fish, dairy, fruits, vegetables), pharmaceuticals (vaccines), chemicals, biological materials (tissues), flowers, live plants. **Characteristics of Perishables:** 1. **Time sensitive:** Short life span. 2. **Temperature sensitive:** Changes in temperature adversely affect the product. 3. **Treatment sensitive:** Rough handling destroys product. 4. **Potentially health risk:** Hazardous food. ### Temperature and Time Issues with Perishables **Why is Temperature Important?** Different temperatures affect bacterial growth: - **0°C and below:** Bacteria do not grow (freezing does not kill bacteria). - **Below 4°C:** Prevents bacteria growth. - **5°C (Refrigeration Temperature):** Slow growth. - **8°C:** Accelerated growth. - **37°C (Body Temperature):** Most active growth. - **60°C:** Continue growth at a slower pace. - **74°C:** Most bacteria die. - **82°C:** Sanitized. - **100°C (Boiling Point):** Sterilization achieved, all bacteria die. **Why is Time Important?** - Bacteria multiply exponentially. - Rate of multiplication increases with temperature. - At the right temperature, bacteria can double in every 15 minutes. ### Scope & Elements of Cold Chain Management **Product Categories:** - **Perishable Food Products:** Fruits, vegetables, meat, seafood, dairy. - **Pharmaceutical Products:** Vaccines, medicine, blood samples, viruses/bacteria, human tissues. - **Chemicals:** With low flashpoints. - **Others:** Flowers, photographic film. **Elements of Cold Chain Logistics:** 1. **Product:** * **Product Knowledge:** Understand optimum storage requirements (temperature, relative humidity). * **Product Handling:** Avoid mechanical damages. 2. **Cold Storage:** * **Optimal storage temperature and humidity:** Affects product deterioration rate. * **Effective monitoring equipment:** Calibrate equipment. * **Storage facilities:** Cleanliness, product segregation, air circulation, freshening. 3. **Cooling Systems:** * Maintain appropriate temperature throughout the supply chain (processing, storing, transporting). * Type of cooling system, monitoring and logging. 4. **Cold Transport:** * Ensures goods remain at stable temperature and humidity levels. * **Cargo flow mapping:** From source to destination, maximize product lifespan. * **Predictability of transit time:** Account for weather, off-loading, traffic, customs delays. * **Reliable transport equipment:** Well maintained, good insulation, adequate airflow and refrigeration. * **Contingency Standard Operating Procedures:** Power outage, equipment breakdown. 5. **Cold Distribution:** * Loading boxes or crates and pallets to distribute goods. * **Minimize damage:** Packaging, cost. ### Food Preservation **What is Food Preservation?** Treating and handling food to stop or slow spoilage, prevent foodborne illness, while maintaining nutritional value, texture, and flavor. **Purpose:** - Preventing growth of bacteria, fungi, and other microorganisms. - Minimizing oxidation of fats (rancidity). - Ensuring safety for consumption. - Extending product shelf life. **Food Preservation Methods (Physical):** 1. **Heat:** Inactivates, eliminates, or reduces spoilage organisms. * **Canning:** Food sealed in cans, heat-treated for sterility (e.g., 15 mins at 121°C). Shelf-life of 2+ years. * **Pasteurization:** Mild heat for short time to kill harmful bacteria, then rapid cooling (e.g., milk, juice). * **Blanching:** Used for vegetables/fruits before freezing (e.g., cauliflower, broccoli). Inactivates enzymes, but product is not sterile. * Level of bacteria count is only reduced. * Necessary to refrigerate to delay bacteria growth for further extension of shelf life. 2. **Refrigeration:** Lowering and maintaining cold temperature (at or below 4°C) to retard bacterial growth/chemical reactions. * **Problems:** Cross-contamination, spoilage (if temperature/humidity too high/low). * **Chilling Injury:** Fruits/vegetables susceptible below recommended temperature. Symptoms appear over time. 3. **Deep Freezing:** Below 0°C. * Water becomes unavailable for bacteria, slows chemical reactions. * Does not kill bacteria, only retards growth. * **Problems:** Ice crystal formation ruptures cell membranes, causing physical damage and changes in texture/flavor. 4. **Quick/Flash Freezing:** Subjecting product to temperatures well below -18°C rapidly to prevent ice crystal formation. * **Methods:** Air blast tunnel freezing, plate freezing, cryogenic freezing (liquid nitrogen). 5. **Dehydration/Drying:** Removing moisture content. * **Methods:** Sun drying, mechanical drying, freeze drying, drum drying, smoking, spray drying. **Food Preservation Methods (Biological):** 1. **Fermentation:** Introducing non-pathogenic bacteria to break down carbs/sugar, produce acid, and reduce pH to control pathogenic bacteria. * Deterioration rate increases with temperature (2-3 times for every 10°C increase). * Shortens shelf life by speeding up chemical reactions, respiration/transpiration, ethylene production, and causing heat injury. **Food Preservation Methods (Chemical):** 1. **Additives:** Using salt, sugar, smoke, or chemicals. * Control deterioration, nutritional losses, and improve aesthetic value (taste, texture, color). ### Importance of Pre-Cooling **What is Pre-cooling?** Rapid removal of field heat from freshly harvested crops (heat gained from sun/ambient temperature). - Removes 'field heat'. - Cools product prior to transportation or storage. **Importance:** - Reduces fruit respiration rate. - Extends crop storage life. - Inhibits growth of microorganisms, reducing post-harvest diseases. **Pre-cooling Methods:** 1. **Room Cooling:** Produce in insulated room with refrigeration. Low cost, but slow. Boxes stacked for air circulation. 2. **Forced-air Cooling:** Fans pull cool air through storage containers. Faster than room cooling. Thermostat can shut off fans. Cooling rate depends on air temperature and flow. 3. **Hydro-cooling:** Immersing produce in cold/running water. 5x faster than air, less energy-efficient. Reduces water loss/wilting. Disinfectant recommended. Not for products sensitive to wetting (e.g., potatoes, onions, garlic). 4. **Vacuum Cooling:** Produce in a vacuum chamber. Water evaporates, removing heat. Best for leafy crops with high surface-to-volume ratio. Water sometimes sprayed to reduce loss. Costly. 5. **Top or Liquid Icing:** * **Top Icing:** Crushed ice added over produce. * **Liquid Icing:** Water/ice slurry injected into packages. * Works well for high-respiration commodities (e.g., sweet corn, broccoli) and dense/palletized packages. ### Performance Measurements in Cold Chain Management **Typical Logistics Key Performance Indicators (KPIs):** - Inventory Accuracy, Delivery Time, Shipment Accuracy. **Specific Cold Chain Measures:** - Frequency and Time Deviations from Storage Temperature Specifications during transport. - **Examples:** - % of shipment within Cold Chain Standard. - % time outside temperature specifications per shipment. - Average time outside temperature specifications per shipment. **Loss Ratio:** $$ \text{Loss Ratio} = \frac{\text{Weight of damaged goods}}{\text{Total weight of shipment}} \times 100\% $$ ### Cold Storage Considerations and Safety **Segregation of Perishable Products:** Different products have different optimum temperature and relative humidity requirements. **Optimal Storage Conditions:** - Extend shelf-life. - Reduce bacterial growth. **Storage above optimum temperature:** - Increases respiration rate, chemical changes, enzymatic processes (over-ripening, off-flavor). - Increases bacterial growth. **Storage below optimum temperature:** - Chilling injury (pitting, browning). - Moisture loss. **Cross-Contamination Considerations:** - **Ethylene:** Ethylene-producing fruits should not be stored with ethylene-sensitive fruits. - **Odors:** Food with strong smells can affect other foods. - **Chemical:** Pesticides, food products. - **Bacteria:** Raw food and ready-to-eat food. **How Ethylene Gas Affects Produce Quality:** - Influences ripening (senescence, aging). - Shortens shelf life. - Causes deterioration, shattering, ripening, and increases decay. - **Rule of thumb:** Avoid storing ethylene-producing fruits with ethylene-absorbing ones. **How Odor Affects Produce Quality:** - Many fruits and vegetables can cause off-flavors and aromas in meat, dairy products, and other produce. ### Cold Storage Warehouse **What is a Cold Storage Warehouse?** - Keeps temperature-sensitive products in a temperature-controlled environment where temperatures are monitored closely. **Types of Cold Store Facilities:** 1. **Cool/Air-Conditioned Facilities (Above 18°C):** Vegetables, fruits, eggs, pharmaceutical materials, floral, milk powder. 2. **Chilled Facilities (2°C to 8°C; 12°C to 18°C; -5°C to 5°C):** Vegetables, fruits, eggs, pharmaceutical materials, floral; highly hazardous food like chilled meat and seafood. 3. **Frozen Food Facilities (Below -18°C; -20°C to -28°C; Below -30°C):** Frozen storage for meat, seafood, ice cream, deep frozen food, blood bank. **Types of Cold Store Facilities (Detailed):** 1. **Reefer (Refrigerated) Containers:** * Transport cargo requiring temperature control. * Basic and cost-effective for small quantities, short-term business. 2. **Blast Freezers and Chillers:** * Rapidly lower food temperature to maintain nutrients and prevent bacteria growth. * Used by commercial kitchens and large restaurants. 3. **Cold Rooms:** * Large refrigerated rooms with specific temperature generation. * Temperatures maintained above (walk-in chillers) or below (walk-in freezers) freezing. * Designed for huge quantities of perishables. 4. **Custom-Built Cold Storage Warehouse:** * Custom facilities, often by 3PLs. * Multi-temperature storage chambers. 5. **Pharmaceutical Grade Cold Storage Warehouse:** * Specialized for bio-pharmaceuticals, blood, vaccines. * Built-in redundancies, security for sensitive/dangerous items. ### Controlling the Storage Environment **Elements in Controlled Storage:** 1. **Insulation:** * **Purpose:** Reduce heat transmission, reduce energy for refrigeration. * **Materials:** Structural Insulated Panels (sandwich of structural board with insulating foam), Spray Foam Insulation (seals gaps, blocks airflow). 2. **Air Filtration:** * Unintentional penetration of warm air. * **Source:** Opening of insulation doors, poor insulation (holes/openings). * **Effect:** Adds heat/moisture, frost on surfaces, increases defrosting frequency. * **Methods to control:** Plastic Strips (interlocking strips create air seal), Insulated Doors, Air Curtains, Air Locks. 3. **Controlled Atmosphere:** * Storage technique to delay ripening and extend shelf life. * Reduces temperature, maintains relative humidity, alters atmosphere (reduces oxygen, increases carbon dioxide/inert gas). * **Environmentally Friendly:** Eliminates chemical pesticides. * **Anoxic Environment Reduces:** Respiration/metabolism, microbial growth, enzymatic spoilage, insects/mites. * **Operating Risks:** Low oxygen can be life-threatening (unconsciousness, brain/heart damage), rescuers at risk. ### Equipment & Monitoring Systems in Cold Store **Material Handling Equipment:** - **Forklifts/Reach Truck:** Battery-operated (LPG/petrol/diesel pose CO risk). Charging systems suit cold chain. - **Robotic Lift Truck:** Fills labor gap, overcomes cold environment issues. Heated handles, floors, cabins; controls for gloves. - **Pallets:** Wooden preferred for low temperature, good cleanliness. - **Roll Cages:** Speed up handling, transfer, stackability. **Loading & Unloading Bays:** - **Docks levellers & loading ramps:** Enclosed/sheltered to protect deliveries, slow thawing. - **Electrical points:** For reefer containers. **Temperature Monitoring System:** - **Temperature Probe/Thermometer:** Manual core temperature measurement. - **Temperature & Relative Humidity (RH) Monitoring System:** - **Temperature measuring device:** Temperature sensors/probes, data loggers. - **Types:** 1. **Standalone temperature data loggers:** Handheld, USB/WiFi data transfer. 2. **Network LAN/WiFi measurement devices:** Automatically transmit data to office PC (wired/wireless). Remote Units collect data, transmit via email/FTP. 3. **Wireless measurement device/wireless base station/gateway:** Internet-connected sensors, immediately transfer alarm status. ### Risk to Personnel Working in Cold Store **Cold Stress:** - Uncomfortably cold conditions leading to net heat loss from the body. - **Signs:** Decreased alertness, restlessness, lack of concentration, impaired manual tasks, numbness, muscle weakness, stiffened joints. - **Occupational health risk:** Shivering, increased oxygen consumption, accelerated respiration/pulse rate, elevated blood pressure, increased cardiac output, vasoconstriction. **Cold-Related Injuries/Illnesses:** - **Hypothermia:** Life-threatening, core body temperature below 35°C. - **Symptoms:** Pale/cold skin, shivering, loss of coordination, slurred speech, fumbling; severe cases: bluish skin, unable to walk/stand, loss of consciousness. - **Frostbite:** Ice crystal formation in skin/tissues at 0°C or lower. - **Affects:** Extremities (nose, cheeks, chin, fingers, toes). - **Symptoms:** Cold, tingling, stinging, aching, numbness; red, then purple/white skin. Leads to tissue damage, amputation. - **Frostnip:** Ice crystal formation in outer skin layer only. No permanent damage. - **Chilblains:** Small, itchy, painful lumps on skin due to abnormal cold response. Red, swollen skin. - **Immersion Injury (Trench Foot):** Prolonged exposure to wet/cold conditions above freezing. - **Symptoms:** Tingling, itching, burning sensation. **Factors Increasing Risk of Cold Injuries:** - Previous cold-related injury. - Predisposing health conditions. - Fatigue, poor physical condition. - Poor nutrition. - Medication. - Alcohol. - Caffeine. - Nicotine (smoking). - Wearing tight clothing. - Under-activity/Over-activity. - Under-dressing. - Length of exposure. - Age. - Dehydration. ### Safety Procedures for Staff 1. **Educating Staff on Proper Clothing Habits:** * **3 layers of loose-fitting clothing:** * Inner wicking layer (synthetic) to draw moisture. * Middle insulating layer (wool) to hold body heat. * Outer layer (Gore-Tex/nylon) for water/wind protection. * Wear wool knit cap, gloves/mittens, insulated safety boots/socks, mask, ear cover. 2. **Educating Staff on Safe Work Practices:** * Work in pairs (look out for each other). * Keep time limits in cold room. * **Freezing Temperature:** 30 mins work, 10 mins break. * **Chilling Temperature:** 1 hr work, 10 mins break. * Awareness of danger/response (symptoms of cold stress, emergency response). * Avoid bad habits (brushing against material with bare skin, prolonged sitting/standing, climbing racks/forklift). * Prevent dehydration (warm drinks, avoid caffeine/alcohol). 3. **Traffic Management:** * Safe pedestrian/vehicular traffic. * Adequate general lighting. * Vehicle horns at intersections. * Drivers observe speed limit. 4. **Other Safe Practices:** * Manage inventories outside cold store. * Pace workload to avoid excessive sweating. * Include sufficient breaks. * New employees get acclimatization time. ### The HACCP Standard **Overview of HACCP:** - **Hazard Analysis and Critical Control Point (HACCP):** Food safety program developed by Pillsbury for NASA (1960s). - Aims to keep food safe by managing critical control points to eliminate, prevent, or reduce food safety hazards (biological, chemical, physical). - Science-based systematic analytical tool to identify microbiological, chemical, and physical hazards. - Identifies and controls potential hazards by reviewing each process step, identifying problem sources, and developing controls. - Used by companies in manufacturing, processing, or handling food products. - Internationally recognized certification system. - **Benefits:** Transforms brand, effective market entry tool, opens new market opportunities. **The Seven Principles of HACCP:** 1. **Conduct a hazard analysis.** 2. **Identify Critical Control Points (CCP).** 3. **Establish critical limits.** 4. **Establish CCP monitoring system.** 5. **Establish corrective actions** when a CCP is not under control. 6. **Establish verification procedures.** 7. **Establish record keeping procedures.** **Preparation for HACCP:** 1. **Assemble the Implementation Team:** Members from all relevant areas/levels of business, possess practical/technical knowledge, or hired external assistance. 2. **Describe the Product:** Document product description, packaging, durability, shelf life, composition, packaging system, intended use. 3. **Identify Intended Use:** Expectation of product usage by end-user (direct consumption, cooked, processed), specific target groups (infants, elderly). 4. **Construct a Process Flow Diagram:** Covers all operation steps. 5. **On-Site Confirmation of Constructed Flow Diagram:** Verify actual process against diagram ("Walk the Line"), check materials, practices, controls, etc. ### HACCP: Principle 1 - Hazard Analysis **2 Steps in Hazard Analysis:** 1. **Hazard Identification:** * "Brainstorm" to identify all potential hazards (biological, chemical, physical) associated with product or process step. * **Biological:** Bacterial, cross-contamination. * **Chemical:** Sanitation residues, cross-contamination. * **Physical:** Flaking paint, dust, broken glass, packaging. 2. **Hazard Evaluation:** * Decide if risk is significant enough for preventive control measures. * Decide on the control measure for the hazard. * One control measure may address multiple hazards; one hazard may require multiple control measures. ### HACCP: Principle 2 - Identify Critical Control Points **Critical Control Points (CCP):** - A point or step where control can be applied and is essential to prevent, eliminate, or mitigate potential risk to an acceptable level (e.g., cooking chicken to 75°C to kill bacteria). - Not all control points are critical; if skipping a step doesn't harm, it's not a CCP. - Decision Tree or other approaches can be used to determine CCPs, ensuring consistent application for each hazard. ### HACCP: Principle 3 - Establish Critical Limits **Critical Limits:** - Maximum or minimum level to which a physical, biological, or chemical hazard must be controlled at a CCP. - Signifies if a CCP is "in" or "out" of control. - Exceeding critical limits indicates direct health hazard or potential for it. - How to set critical limits (boundaries for product safety): Government regulations, industry/company standards, scientific data, consultation with experts. - **General Criteria:** Process time, shelf life, temperature, relative humidity, sensory appearance, microbiological information. ### HACCP: Principle 4 - Establish CCP Monitoring System **CCP Monitoring System:** - Continuous scheduled measurements or sampling to ascertain if CCPs are within critical limits. - If not continuous, frequency must ensure CCP is in control. - **Special devices:** Thermometers, thermo-hygrographs, metal detectors. - **Procedure addresses:** Who, what, how, when to monitor. - **Monitoring procedures:** Quick, easy, able to detect loss of control, provide timely information, accurately documented. ### HACCP: Principle 5 - Establish Corrective Action **Corrective Actions:** - When critical limits are not met, prompt actions are taken: - **Regain control:** Immediately adjust process to bring product into compliance. - **Stop the line:** Hold all non-compliant products. - **Correct root cause:** Prevent recurrence. - **Pre-planned rectifying actions:** Quarantine affected product, back-up plans for equipment breakdown. ### HACCP: Principle 6 - Establish Verification Procedures **Verification Procedures:** - Auditing activities to confirm HACCP system is working. - Checks if hazards are reduced and HACCP is implemented properly. - Carried out by quality assurance or third parties periodically. - Discrepancies may require re-scrutiny and re-design. - **Examples:** Review HACCP systems/records (product descriptions, flow documentation), check monitoring records (CCPs in control), review records (deviations, complaints), observe operations, check calibration, obtain evidence of effectiveness (lab tests). ### HACCP: Principle 7 - Establish Record Keeping Procedures **Why Keep Records?** - Evidence that CCP is in control. - Correction of deviations. - History of problem-solving and learning. - Record must be complete and eligible (without proof, activity is considered not performed). **Types of CCP Records:** - **Processing:** Receiving time, storage. - **Storage and distribution:** Temperature, humidity. - **Deviation and corrective actions:** Validation records, HACCP plan modification records. - **Staff Training:** Records indicating staff understanding of hazards, controls, processes. ### Packaging and Material Handling Equipment **What is Packaging?** - Technology of enclosing or protecting products for distribution, storage, sale, and use cost-effectively. - Coordinated system for preparing goods for transport, warehousing, logistics, sale, and end-use. **Role of Packaging:** - Contains, protects, preserves, sells, transports, informs. **Right Choice of Packaging:** - Ensures product is delivered in the right condition, place, position, sequence, for the right cost, using the right methods. **Levels of Packaging:** - **Primary packaging:** Envelops product for protection against gases, moisture, microorganisms, insects, rodents. Forms sales unit for customer (content, branding, "best before date"). - **Secondary packaging:** Groups primary packages for efficient handling (e.g., cardboard boxes, trays). Physical protection from damage, shock, vibration. - **Tertiary packaging:** Groups secondary packaging for bulk handling, protection in warehouse/shipping. Palletized into unit load. **Types of Packaging Materials:** 1. **Natural Materials:** * **Baskets (bamboo, rattan, straw palm leaves):** Disadvantages - difficult to clean, sharp edges. * **Sacks (jute, kenaf, sisal, cotton):** Advantages - cheap, low weight/volume. Disadvantages - low protection against puncturing, vibration, impact. 2. **Wood:** * Used for secondary/tertiary packaging (food/beverage, transport). * **Advantages:** Good mechanical strength, resistance to high humidity, inert, resealable, recyclable, reusable. 3. **Glass:** * Oldest high-barrier food packaging. Compatible with food/pharmaceuticals. * **Disadvantages:** Heavy, bulky, low shock resistance. * **Advantages:** Chemically inert, odorless, sterilizable, barrier to moisture/gas, pressure resistant, moldable, transparent, highly recyclable. 4. **Metal:** * Tin-plate or aluminum. Tin-plated steel for food cans. Aluminum for drinks cans, frozen/chilled ready meals. * **Characteristics:** Strong, rigid, barrier to gas/moisture, pressure resistant/tolerant, corrosion resistance (coatings), sterilizable, directly decorated/labeled, recyclable. 5. **Paper:** * Plain paper has poor barrier properties. Laminated with waxes/resins/lacquers for strength/barrier in primary packaging. Cartons for secondary packaging. * **Advantages:** Low cost, easily decorated, recyclable, lightweight. * **Disadvantages:** Easily damaged by handling, stacking, moisture. 6. **Plastic:** * Most popular primary packaging. * **Advantages:** Lightweight, inexpensive, tailored to specifications, displays information, sealable (prevents water loss). * **Disadvantages:** Short usage life, little protection from injury, permeable to light/gases/vapors, health concerns (migration of molecules), environmental harm (non-biodegradable). ### Packing Methods & Practices **Keep the Heat Out (Insulation):** 1. **Styrofoam:** Lightweight, thick expanded polystyrene foam. Used for temperature-sensitive shipments worldwide. Disadvantage: Low mechanical strength. 2. **Insulated Box with Liners:** Aluminum sheets or synthetic foam liners. Used for chilled/frozen food packaging. Economical, lightweight, clean, available in shapes/sizes. Wax-coated for water resistance. 3. **Molded Plastic Containers:** Reusable, versatile, tailored to specifications, rigid, smooth, easily cleaned, stackable. Most limiting factor: High cost, pilferage risk. 4. **Thermal Covers:** Tertiary packaging layer. Safeguard against direct sunlight, radiated heat, windchill, sub-zero temperatures. Allows temperature-sensitive produce to remain stable without condensation damage. **Keep it Cold (Coolants):** 1. **Using Ice:** Topping with ice maintains high relative humidity. Used for water-tolerant, non-chilling sensitive products (e.g., carrots, sweet corn, lettuce, spinach, radishes, broccoli). 2. **Using Gel Packs/Ice Packs:** For refrigerated items to maintain desired temperature. Refrigerate 24-48 hrs prior. Lasts 12-36 hrs. 1 lb gel pack per 3 lbs perishables is optimal. 3. **Using Phase Change Material (PCM):** Stores/releases large amounts of energy. Maintains constant temperature during phase change (solid to liquid). **Applying Modified Atmosphere Packaging (MAP) Concept:** - Creates optimal gas balance inside package for low respiration activity (delays ripening). - Seals single pallet loads in plastic sheets with wide tape. - Slight vacuum and CO2 introduction via small hose. **Other Packing Practices:** 1. **Vacuum Packaging:** Extends shelf life of vegetables by withdrawing air (suction machine). Retards enzymatic reactions and bacterial spoilage. 2. **Plastic Liner in Fiberboard Carton:** Minimizes bruising, reduces water loss, contains water vapor to increase RH. 3. **Fiberboard Dividers:** Wooden inserts or folded fiberboard triangles. Strengthens cartons, prevents fruits from vibrating. 4. **Strapping and Cornerboards for Unit Loads:** Plastic/metal straps secure load. Fiberboard/plastic/metal cornerboards provide stable unit load. 5. **Carton Boxes with Holes:** For handling. Allows cold air circulation to remove respiratory heat, water vapor, and gases. 6. **Wooden Crates:** Constructed for air circulation. Good resistance to high humidity, mechanical strength, stackability. Relatively inert, resealable, recyclable, reusable. Disadvantages: heavy, costly, difficult to clean, sharp edges. ### Passive Packaging System vs Active System **Passive System:** - Uses refrigerants (icepacks, dry ice) to maintain temperature over time. - Needs sensors to monitor internal temperature. - Usually single-use and disposed; some can be recycled. **Active System:** - Electronic source for active temperature control, adjusts temperature. - In-built sensors for data logging. - Leased and returned after use. **Packaging Types for Vaccines:** 1. **Thermal Package:** Outer container, insulation on all 6 faces, product in center, standalone cooling system. Can include embedded temperature monitor. Used once, discarded. Shipment for 40-120 hrs. Small capacities ( ### Transportation of Temperature Sensitive Products **Selection of Transportation Mode:** | Factor | Air | Sea | | :---------------- | :------------------------------------ | :---------------------------------------- | | **Capacity** | Limited | Yes | | **Cost** | Premium | Economical | | **Reliability** | Limited equipment available | Reliable With Technician | | **Transit Time** | Fast | Slow but allows food to mature | | **Product Perishability** | Not Applicable | Yes | | **Shipment Value** | High | Low | | **Others** | Dry Ice Restriction | Delays in Adverse Weather Conditions | **Types of Vehicles used for Cold Chain Transport (Road):** 1. **Isothermal Trucks:** Isolating walls, doors, floors limit heat exchange. Maintain output temperature for short periods. Used for last-mile delivery of fresh produce not requiring precise temperature control. 2. **Refrigerated Trucks:** Refrigeration unit built directly on frame. Can reduce interior temperature for average exterior temperatures up to 30°C to -20°C. Some have integrated electric standby reefer units (fuel saving). Transport all types of temperature-sensitive products. **Types of Vehicles used for Cold Chain Transport (Sea):** 1. **Reefer Containers:** 20-footer containers with refrigeration system at rear. Maintain cargo temperature (-30°C to +30°C). Cold air blown in at bottom through T-Bar Floor, warm air drawn off below ceiling. Circulating fans force warm air through cooler. Use for temperature-sensitive goods in container ships. Rely on external electrical power (warehouse, quay, vessel) or diesel power (vehicle). Equipped with redundancy refrigeration. 2. **Reefer Ships:** Special cargo ships for refrigerated goods. Transport fruits, meat, fish, vegetables, dairy products (-30°C to 12°C). Crew members are experts in perishable handling. **Types of Vehicles used for Cold Chain Transport (Air):** 1. **Reefer Aircraft Containers (Unit Load Device):** * **Active refrigeration:** Mechanical refrigeration system, uses dry ice as refrigerant, battery-operated thermostat controls fan. * **Passive refrigeration (for Pharmaceuticals):** * **Cold Boxes:** Insulated reusable containers with coolant packs. For vaccine supplies between stores/health facilities. Capacity 5-25 Liters, cold life 48-96+ hrs. * **Disposable Insulated Boxes:** Insulated containers (carton/molded foams). For long-distance vaccine transport. Varying capacity, temperature range, cold life. For air transport with hold times up to 120 hrs. ### Controlled Atmosphere (CA) for Transportation of Perishables - Transport of fruits/vegetables in atmosphere with reduced oxygen, high carbon dioxide, low temperatures, and high relative humidity. - **Purpose:** Prolong shelf life, maintain quality, reduce spoilage. Controls ripening, reduces weight loss, delays softening, inhibits browning/decay, favors flavor retention. - Transport CA systems used only with marine containers. **Types of CA Systems:** 1. **Active CA Systems:** Establish and maintain atmosphere within reefer container. Permanently built into refrigeration unit. Draw outside air, separate nitrogen, establish oxygen level, add carbon dioxide. 2. **Passive CA Systems:** Only maintain atmosphere after gas purging. Liquid or gaseous nitrogen pumped in to purge existing air (2-5% oxygen). - Both types continuously monitor and adjust oxygen/carbon dioxide. All include potassium permanganate scrubbers to remove ethylene. ### Maintaining Quality of Temperature-Sensitive Products in Transit **Compatibility of Load:** - Store products with same storage temperature and relative humidity range. - Segregate ethylene-sensitive and ethylene-producing produce. - Segregate products with strong odor contamination characteristics. **Shipping Conditions:** 1. **Food Grade Containers:** * **Inside:** No strong/offensive odors, clean, dry, sound, sturdy, rust-free frame. Waterproof (tightly closed doors). * **Outside:** Clean, painted light colors (reflect heat). 2. **Temperature & Relative Humidity Control:** * Shipper provides instructions: pre-cooling, required temperature/RH. * Carrier completes checks before release: diagnostic check of refrigeration unit, set temperature/RH, decal with requirements. **Ventilation Control:** - Replaces air inside container with outside air. - Removes accumulated respiration gases (carbon monoxide, ethylene, odor) from ripening. - Kept to minimum, determined by cargo characteristics. - **Impact of more ventilation:** Reduced refrigeration efficiency, more defrosting, interrupted air circulation. **Pre-Cooling of Load:** - Rapidly removes heat from produce before shipping/storage. - All refrigerated products must be pre-cooled to recommended temperature before loading. - Reefer containers only maintain temperature, not lower it. - Warm/improperly pre-cooled produce degrades quality. - Refrigeration system may over-adjust, causing chilling injury. **Pre-Cooling of Container:** - Transferring cold products into warm container can cause: surface thawing (condensation), freezer burn (dehydration), increased defrosting. - Should occur in enclosed loading bay (air lock/cold tunnel) with similar temperatures. - If no enclosed bay, cool container to just above dew point to remove heat from walls. - **Dew point:** Temperature at which air becomes saturated with water vapor. **Cargo Stowage:** - **Prevent Airflow Obstruction:** Stack cargo as solid block, no large empty spaces (can collapse), no spaces between cartons (prevents "short circuit" airflow). - Use filler (cardboard) if cargo doesn't cover entire floor. - Do not shrink-wrap palletized cargo (blocks airflow). - If pallets wrapped in plastic, do not cover bottom/top of cartons. - Stack cartons with holes face front-to-back for air circulation. - Secure cargo with airbags, load locks, wooden planks to minimize movement. **Packaging:** - **Correct Packaging:** Allows ventilation for respiration, ethylene, moisture, carbon dioxide. - **Aiding Temperature Management:** Appropriate vent cartons for chilled cargo promote proper airflow. ### Temperature Monitoring of Products in Transit **Temperature & RH Data Logger:** - Battery-powered electronic device records temperature/RH. - Placed near/among perishable cargo. - Accuracy: ±0.5°C temperature, ±3.0% RH. - Provides complete time/temperature history. - Records at intervals (e.g., 10 mins for 2 weeks, >2,000 data points). - Allows download to computer to verify temperature control. **Data Collected Used For:** - Locating risk hotspots, highlighting issues, route/provider qualification, validating product integrity. **Temperature Monitor Card:** - Indicator strip changes color when exposed to high temperatures. - Estimates length of exposure. - Color change is cumulative, relates to heat exposure over entire shipment. **Timestrips:** - Records hours shipment breaches set temperature. - Can indicate up to 4 hours of breach. - Different Timestrips for different products. **Temperature (Freeze) Indicators:** - **Freeze Indicators:** Tells if product exposed to freezing temperature. - **Freeze Watch:** Tells if product exposed to freezing temperatures for >1 hour (vial bursts, releases colored liquid). **Freeze Tags:** - Electronically shows if product exposed to temperature below 0°C ±0.3°C for >1 hour (changes from "good" to "alarm"). **Monitoring of Reefer Containers:** - **Manual Recording:** Technician checks container settings, records info in log. Time consuming. - **Remote Monitoring:** Microprocessors on reefer unit record/transmit temperature via internet (if comms module) or power cable to ship's computers. Data loggers within container. - **Integrated Solutions:** Cloud-based solutions, GPS temperature monitoring for road transport.