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Colour prints for: FDFTECCCS4A and FDFTECLEG4A Colour prints FDFTECCCS4A: Control food contamination and spoilage FDFTECLEG4A: Apply an understanding of legal requirements in food production 1 © NSW DET 2007 1. A cockroach found in a fish dinner—The customer is not likely to return to this shop! This is obviously a gross example of visible contamination. It is made worse because cockroaches harbour many potentially pathogenic (dangerous) micro-organisms. 2. Maggots (larvae of flies) in food—Maggots take some time to grow to this size, so the food has been left exposed for too long. 3. A cigarette butt in jam—This was probably put there by the customer—if it had been added in the factory, it would be at the top of the jar! 4. Animal hair in meat-pie filling—It makes you wonder where the meat came from! 5. Ropey’ milk—Many bacteria, such as Bacillus subtilis, have a ‘capsule’ or slime layer. There are so many bacteria in this milk that it can form strands of slime or ‘ropes’. These bacteria can also cause ‘rope’ in baked products like bread. 6. Using a microscope—Magnification of 1000x makes a bacterium one micrometer (‘micron’) in actual size appear 1 millimetre in size, and is used to help identify micro-organisms. 2 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 7. Bacteria—The original magnification of this photo was 1000x. You can see that these bacteria are round (cocci) and stick together in clusters. The colour is staining to make the bacteria more visible. If the Gram stain technique has been used, they would appear blue (Gram positive) or red (Gram negative). These are Gram negative. 8. Bacteria—These are mostly rod-shaped bacteria (bacilli), with a few darker cocci. The smaller, clear ovals are spores. Because of their tough wall, spores do not stain easily, so appear clear. 9. Bacteria.—A mixture, mostly Gram positive (blue stained) cocci. These ones were taken from some rotting, putrid meat. 10. Bacteria—In the centre is a chain of large rods. If you look carefully you may see that two of these are in the process of dividing in two (binary fission). 11. Bacteria—Some different rod and sphere-shaped bacteria. Some are dividing in two. The grape-like clusters of cocci are Staphylococci; the chains are Streptococci. 12. Mould: Rhizopus—You can see the round black sacks which contain the spores (sporangia); the hyphae supporting the sporangia; and the finebranched hyphae which act like roots (rhizoids). 3 © NSW DET 2007 13. Mould: Penicillium—The chains of spores grow in a brush formation. Many of the spores have matured and have been released. These can spread by wind or water and germinate to form new moulds. 14. Yeast—Most yeasts are oval shaped. Some of these have formed ‘buds’ which is their usual method of reproduction. 15. Yeast—Yeast cells in various stages of budding. The buds are labelled ‘Bu’. 16. Volvox, a protist—Each large sphere is a colony of a few hundred individual cells. ‘Daughter’ colonies are forming inside the large colonies. 17. Chlamydomonas—The cells of this protist are similar to Volvox cells but they are individuals, and do not form colonies as Volvox does. Protists are often found in water. 18. Virus particle—Viruses are not cells, but genetic material (DNA) in a protein envelope. This photograph was taken with an electron microscope, because viruses are too small to be seen even with a powerful conventional light microscope. 4 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 19. Drawings of viruses—Viruses replicate (reproduce) by parasitising people, animals, plants or even bacteria cells. Each virus is adapted to one type of cell. 20. This print shows a typical petri dish. It contains the nutrient agar gel. Micro-organisms are ‘inoculated’ onto this gel and the dish is then ‘incubated’ at a temperature which encourages their rapid growth. During the incubation period of several days, the micro-organisms multiply very rapidly and form visible colonies (which comprise many millions of individual micro-organisms). 21. A wire ‘loop’ is used to take samples of bacteria from colonies growing on the jelly. 22. Placing a petri dish in an incubator. 23. An electron microscope photograph of a microbial cell with flagellae. 24. Clostridium botulinum—The clear areas within some cells are spores which can be killed only by many hours of boiling or some minute of high-temperature treatment. This bacterium forms a potent nerve poison, so manufacturers of canned food must destroy the spores by pressure cooking. 5 © NSW DET 2007 25. Colonies of bacteria growing on nutrient agar jelly in a petri dish. A sample from one colony is often transferred to a new petri dish as shown in the next photo. 26. ‘Streaks’ in a petri dish—A sample of bacteria is spread out over the surface of the agar gel using a wire loop in successive streaks as shown in the diagram. The last streak separates individual bacteria, so after incubation, separate colonies appear on the gel. 27. Penicillium mould on oranges. 28. The sample of fast-frozen apple shows less loss of liquid (‘drip’) on thawing than the slow-frozen sample. 29 Characteristics of Salmonella. Characteristics of Staphylococcus. 30. 6 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 31. Clostridium perfringens—The bacteria are stained purple and are rod shaped. A few, almost clear spores are visible. The red material is debris from the food the bacteria were growing in. 33. Bacillus cereus—rod-shaped bacteria that can cause food poisoning from cereal foods. Some unstained spores are just visible. 35. Dirt and obvious rough handling of these rabbits have made them unsuitable for use. 32. Escherichia coli or E coli bacteria—These are very common in people’s intestines. Some E coli are pathogenic and cause vomiting and diarrhoea: a common cause of travellers’ ‘tummy upsets’. 34. Packages of sliced meats—The cloudiness or turbidity in the liquid indicates that bacteria are growing and the product should not be used. 36. Capsicums showing spoilage—Bacteria can grow in some vegetables with low acidity, causing texture breakdown, colour changes and a putrid smell. Have you ever smelt a rotten potato? 7 © NSW DET 2007 37. The slime and discoloration on the gills of this flathead are the result of bacterial growth. The smell could not be photographed! Moist, neutral pH conditions allow the rapid growth of bacteria. 39. Nuts are too dry for bacteria, but if stored in a humid place, mould can grow. Even if the mouldy odour and appearance can be removed, these nuts must not be used because of the possibility that mycotoxins are present. 41. Similar deterioration in green prawns with ‘black head’. 38. Mould has spoiled these dairy products. The acidity reduces bacterial growth, but mould finds slight acidity ideal. 40. The prawns on the left have ‘black head’. This is a form of enzymic spoilage. 42. A burst can—The acid in the food has corroded the metal of the can, forming hydrogen gas. 8 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 43. Fresh (left) and old (right) eggs—The fresh egg has a small firm yolk and distinct, thick white. The changes are physical—water moving into the yolk; and chemical—breakdown of the white proteins. The stale egg is edible, but quality is poor for frying or boiling. 44. A fresh egg.—You can clearly see the rope-like chalazae which hold the yolk in the centre of the egg. 45. A stale egg with a very ‘runny’ white. 46. Carrots canned in glass containers— The ‘unprocessed’ jar shows turbid or milky liquid indicating growth of micro-organisms in the liquid. The liquid in the ‘boiled’ jar appears clear, but boiling does not destroy spores so there may be some bacteria from germinated spores. If any Clostridium botulinum has grown, this food could be very poisonous. ‘Pressure cooked’ is the normal process used which ensures the food is effectively preserved. 47. Cockroach nymphs—These immature small cockroaches are often mistakenly thought to be harmless. If you see these, it means you have a breeding population of cockroaches. 48. Black rat, a good climber. 9 © NSW DET 2007 49. Rad droppings from a brown rat—These are often the first sign of infestation. Other signs are gnawing damage and greasy marks where rats run along, touching a wall. 50. The small dark one is a rodent dropping. The others are jelly beans. 51. A rice weevil on a grain of wheat. 52. Weevils on rice. 53. A confused flour beetle (so called because it is easily confused with the rust red flour beetle). These are about the size of a weevil and cause similar problems. 54. Some examples of pest insects. 10 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 55. Using high-pressure equipment to wash food processing machinery. 56. Servery area showing clean tiled walls and floors, coving, and bain maries protected from customers. 57. Bain maries with plastic carving board and hotholding cabinets. 58. Waste disposal unit for food scraps. 59. Wash-up area (scullery) showing double-bowl wash tubs, waste disposal and drying racks. 60. Food preparation area showing construction for ease of cleaning. 11 © NSW DET 2007 61. Unsatisfactory storage: wooden shelves, spillage, overcrowding and food on floor. 62. Food stacked too high, causing damage to containers. 63. It is a long time since the bottom of this refrigerator was cleaned! 64. Unclean shelves under food preparation bench: spilled food, absorbent material, uncovered containers. 65. Towelling on a bench in the bar of a fairly expensive restaurant. It is moist, and shows mould growth. 66. Cleaning and sanitising—Clear away bulk soil, pre-rinse, detergent clean, rinse, sanitise (eg 50mg/L available chlorine for correct contact time eg 30 seconds), rinse, drain/dry and document 12 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 67. Use of high pressure spray during cleaning and sanitation 68. Seafood auction (This photo taken some time ago. The new process minimises potential for contamination) 69. Fishing trawlers—New requirements mean that the trawler must be maintained in a more hygienic state than the one pictured here 70. Seafood defect— Furunculosis infection by the bacteria Aeromonas salmonicida. This fish is not fit for consumption 71. 72. 71 and 72. Salami aging—During this process, the ph and Aw should both drop to levels that ensure the uncooked fermented smallgoods are stable at room temperature. Note that it is not unusual for mould growth (non-pathogenic) to occur at this stage. This is generally rinsed off before sale. (Sometimes it is wiped off with a vinegar solution.) 13 © NSW DET 2007 73. Double hook can seam—The lid is sealed (crimpled) onto the base of the can in a two-stage roller process. As you can see, the lip in the lid is firmly tucked in and under the lip of the body of the can. This results in an airtight (hermetic) seal, so no new micro-organisms (or other contamination) can ever enter. It now only remains for the sealed can and contents to be heat processed (retorted) to eliminate/control any existing micro-organisms. 74. This picture shows the lid and can base before sealing. ‘Section B’ of the picture depicts the flexible compound that is embedded into the lip of the lid. This compound assists in making the airtight seal when the lid is rolled/sealed onto the can base. 75. The rolling of the lid onto the base is a CCP and must be done correctly to ensure the airtight seal. The monitoring procedure involves qualitative (visual inspection) as well as quantitative evaluation of the seam using a micrometer to measure that the seam meets the required critical limits. The top of the picture shows one of the measurable features that can be monitored, ie the severity of wrinkling (damage) on the lid seal. In this case the ‘value’ must be no more than mid range. 76. This picture shows the rapid freezing of cartons of freshly packed food. The cartons are spaced to ensure super cold air (eg 40oC) is circulated around the cartons. This results in quick freezing ensuring that the core temperature is reduced (eg, -18oC) within hours. 14 © NSW DET 2007 Colour prints for: FDFTECCCS4A and FDFTECLEG4A 77. The first small bottle on the left shows fresh oysters. They are of even colour with distinct black (filter) strip, evenly dispersed through the clear/clean water. The middle tall bottle shows oysters on the turn in cloudy water indicating the start of microbial spoilage. The last bottle of oysters should never be consumed as the floating oysters indicate an advanced stage of microbial spoilage. 78. Black rot in eggs—This form of bacterial spoilage would certainly catch everyone’s attention (and probably clear out the kitchen very quickly as it would have a very offensive putrid smell). 79. Red rot in eggs, generally caused by Serratia bacterial spoilage. 80. Egg defect showing a blood spot (fertilised egg) and double yolk. Neither of these constitutes a food safety hazard, but is generally rejected as nonstandard. 81. Serratia bacterial spoilage again. This time causing a dramatic red discolouration in milk 15 © NSW DET 2007 16 © NSW DET 2007