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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
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© 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.
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© 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).
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© 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.
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© 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.
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© 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.
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© 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?
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© 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.
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© 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.
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© 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.
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© 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.
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© 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
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© 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.)
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© 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.
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© 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
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© NSW DET 2007
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© NSW DET 2007