2. CONTAMINATION
• Latin word contaminat = “made impure.”
• Contaminate = pollute
• Contaminate something = impure or
hazardous.
3. SPOILAGE
• The action or process of spoiling of perishable
goods.
• Spoiled food = damaged/ injured food
undesirable for human consumption
• Food spoilage causes:-
Physical injury
Enzyme activity
Microbes
4. PRESERVATION
• The action of preserving something.
• Food preservation – action of preserving food
in order to maintain it as desirable for human
consumption.
7. Contaminating sources
• Sugarcane
• Soil
• Handlers
• Transportation
• Air
• Debris/ fine particles on the sides/ joints of
troughs at the plant
• Industrial equipments & machines
8.
9. Contaminants
• Slime producers, like species of Leuconostoc
and Bacillus; representatives of the genera
Micrococcus, Flavobacterium, Alcaligenes,
Xanthomonas, Pseudomonas, Erwinia, &
Enterobacter.
• A variety of yeast, chiefly in the genera
Saccharomyces, Candida, & Pichia.
• A few moulds.
10. Stages when organism gets added
• Bagging of raw sugar
• Sugar refining
• From equipment
• From flume & diffusion battery waste
14. Contaminants
• Enter between its flow & being boiled &
concentrated
• A moderate amount of growth - improve flavor
and color
• The sap often stands under conditions that favor
excessive growth of micro organisms and hence
spoilage.
• Mostly psychrotrophic, G - rods + yeasts + molds
• Bacterial count - <10,000/ml
25. SUCROSE
• At each processing stage it get more n more
purified
• Sugar concentration increases – crystallization
– sugar crystals + molasses
• Purity ∞ 1/micrbial load
26. Raw sugar cane juice
• Low sugar content
• Good source of accessory foods for microbes
• Readily deteriorates
• Spoilages until clarification
Gum/ slime : L. mesenteroids/ L.dextranicum
Levan : Bacillus spp. (mostly); yeasts/ molds(rarely)
27. Sugar in storage
• Liquid sugar :-
i. 67 – 72 brix sugar
ii. support yeast’s growth (Saccharomyces,
Candida & Rhodotorula) & molds from air.
• Absorption of atmospheric moisture at
surface – microbial growth – product
deterioration.
Preservation : circulation of filtered sterile air
28. Molasses & syrups
• Microbial spoilage – not common
• Tough to heat sterilize
• Canned one’s : spoiler’s osmophilic yeasts
• Exposure to air – air left in containers –
spoilage before sealing
• Acidic one’s – hydrogen swells on storage
29. SL.
NO.
SPOILAGE TYPE CAUSATIVE AGENT
1 Ropy or stingy sap Enterobacter aerogenes (mostly), Leuconostoc
(responsible)
2 Cloudy, sometimes greenish sap P. fluorescens + Alcaligenes spp. + Flavobacterium
spp.
3 Red sap Colored by pigments of red bacteria, e.g.
Micrococcus roseus, /of yeasts / yeast like fungi,
4 Sour sap (a group o spoilages
without marked color change
but have a sour odor)
Variety kinds of bacteria or yeasts
5 Moldy sap Molds
30. Honey
• ≤ 25% moisture
• 70 – 80 % sugar
• Sugars : glucose(mostly) & levulose
• Ph : 3.2 – 4.2
• Chief spoilers : Zygosaccharomyces, such as
Z. mellis, richteri, or nussbaumeri, or Torula
(Cryptococcus) mellis.
• Penicillium spp. and Mucor spp. have develop
slowly.
31. Special theories for initiation of growth of yeast/
causes of spoilage of honey
• Honey- hygroscopic- surface dilution- yeasts
multiplication & adaptation to high sugar
concentrations.
• Crystallization of glucose hydrate from honey-
lowers sugar concentration in solution
• Long standing- yeast’s gradual adaption to
high sugar concentrations.
32. Factors effecting microbial growth in honey
• Critical moisture content of yeast – 21%
• Degree of sucrose inversion to by bees
• Available N content
33. Honey fermentaion
• Slow, lasts for months
• Chief products : CO2, alcohol, & non-volatile
acids (give off-flavor)
• Usually accompanied by darkening &
crystallization
34.
35.
36.
37. Candy
• Not subject to microbial spoilage - high sugar
& low moisture content.
• Exceptions - soft fondant/ inverted sugar
centered chocolate- burst or explode.
• Yeast growth develops a gas pressure - disrupt
the entire candy/ push out some of sirup or
fondant through a weak spot in chocolate
coating.
• Often this weak spot is on the poorly covered
bottom of the chocolate coating.
38. PRESERVATION
• Storage conditions: keep out vermin -the sugar
remains dry.
• Can or sugar beet - stored in a controlled
atmosphere.
• Fungal growth inhibition by 6% CO2 & 5% O2.
• During sugar manufacturing the refining processes
reduce microbial load present
39. • Chemical preservatives used in sugar refining.
• Care to avoid buildup of organisms and their
spores during processing.
• Numbers may be reduced by irradiation with
UV/ heat + H2O2
• Chocolate bursting - prevented by a uniform,
thick chocolate coating & use of fondant/ other
filling.
40. • Sirups and molasses - stored at cool T.
• The boiling process (evaporation of maple sap
to maple sirup) kills the important spoilage
organisms.
• Honey crystallization: heat to at least 71 C,
hold there for 5 minutes, and cool promptly to
32.2 to 38 C.
• Molasses & sirups : high osmotic P (∞ degree
of sucrose inversion). Mold growth prevented
by complete filling of container & reduced by
their periodic mixing.
41. REFERENCES
• Dennis C. Westhoff, William C. Frazier –
Food Microbiology – fourth edition - The
McGraw Hill companies – NewDelhi- pg.no. :
187 – 195.
• James M. Jay– Modern Food Microbiology –
third edition – AVI book publications– usa-
pg.no. : 193, 244-245
