CONTAMINATION, PRESERVATION & SPOILAGE OF SUGAR & SUGAR PRODUCTS

1. CONTAMINATION, SPOILAGE &
PRESERVATION
SUGAR & SUGAR PRODUCTS

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.

5. CONTAMINATION
Sucrose Maple sugar
• Honey
Candy Honey

6. SUCROSE

7. Contaminating sources
• Sugarcane
• Soil
• Handlers
• Transportation
• Air
• Debris/ fine particles on the sides/ joints of
troughs at the plant
• Industrial equipments & machines

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

11. Microbial action
Cutting of cane
Extraction
Clarification
Result
• Sucrose inversion
• Sugar destruction

12. MAPLE SUGAR

13. Contaminating sources
Tree
Collection
bucket
Handlers
Instruments
Air
Plastic
tubings
spouts

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

15. Prevention of contamination
• Paraformaldehyde taphole pellet
• Plastic tubing

16. HONEY

18. Contaminats
Yeast Bacteria
Bee
(intestine)Nectar

19. Contaminats
• Streptococci/ enteric bacteria – rare
• Common isolates – lysosome +
• Antibiotics- streptomycin, neomycin
• C. botulinum – infant botulism
• Gluconobacter & Lactobacillus – present
during maturation of nectar to honey

20. CANDY

21. Contaminating sources
MICROBIAL LOAD – 0-2 MILLION BACTERIA/ PIECE

22. Classification of candies &
confectionaries
• Cold processed • Hot processed

23. Result of contamination
• Food poisoning outbreaks
• Salmonellosis

24. SPOILAGE
• Osmophilic/ xerotolerant microbes
• Principle spoilage flora : Saccharomyces spp. &
certain moulds.
• Bacterial spoilers – Bacillus spp. & Leuconostoc
spp.
• Sugar concentration ∞ 1/micrbial load

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

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

42. HIMA HARIDASAN