contamination, spoilage & preservation of sugar and sugar products
TRANSCRIPT
CONTAMINATION, SPOILAGE & PRESERVATION
SUGAR & SUGAR PRODUCTS
CONTAMINATION
• Latin word contaminat = “made impure.”
• Contaminate = pollute
• Contaminate something = impure or hazardous.
SPOILAGE
• The action or process of spoiling of perishable goods.
• Spoiled food = damaged/ injured food undesirable for human consumption
• Food spoilage causes:-Physical injuryEnzyme activityMicrobes
PRESERVATION
• The action of preserving something.
• Food preservation – action of preserving food in order to maintain it as desirable for human consumption.
CONTAMINATION
Sucrose Maple sugar
• Honey
Candy Honey
SUCROSE
Contaminating sources
• Sugarcane • Soil• Handlers• Transportation• Air• Debris/ fine particles on the sides/ joints of
troughs at the plant• Industrial equipments & machines
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.
Stages when organism gets added
• Bagging of raw sugar
• Sugar refining
• From equipment
• From flume & diffusion battery waste
Microbial action
Cutting of cane
Extraction
Clarification
Result
• Sucrose inversion
• Sugar destruction
MAPLE SUGAR
Contaminating sources
Tree
Collection bucket
Handlers
Instruments
Air
Plastic tubings
spouts
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
Prevention of contamination
• Paraformaldehyde taphole pellet
• Plastic tubing
HONEY
Contaminats
Yeast Bacteria
Bee(intestine) Nectar
Contaminats• Streptococci/ enteric bacteria – rare
• Common isolates – lysosome +
• Antibiotics- streptomycin, neomycin
• C. botulinum – infant botulism
• Gluconobacter & Lactobacillus – present during maturation of nectar to honey
CANDY
Contaminating sources
MICROBIAL LOAD – 0-2 MILLION BACTERIA/ PIECE
Classification of candies & confectionaries• Cold processed • Hot processed
Result of contamination
• Food poisoning outbreaks
• Salmonellosis
SPOILAGE• Osmophilic/ xerotolerant microbes
• Principle spoilage flora : Saccharomyces spp. & certain moulds.
• Bacterial spoilers – Bacillus spp. & Leuconostoc spp.
• Sugar concentration ∞ 1/micrbial load
SUCROSE
• At each processing stage it get more n more purified
• Sugar concentration increases – crystallization – sugar crystals + molasses
• Purity ∞ 1/micrbial load
Raw sugar cane juice• Low sugar content
• Good source of accessory foods for microbes
• Readily deteriorates
• Spoilages until clarificationGum/ slime : L. mesenteroids/ L.dextranicumLevan : Bacillus spp. (mostly); yeasts/ molds(rarely)
Sugar in storage• Liquid sugar :-i. 67 – 72 brix sugarii. 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
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
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
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.
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.
Factors effecting microbial growth in honey
• Critical moisture content of yeast – 21%
• Degree of sucrose inversion to by bees
• Available N content
Honey fermentaion
• Slow, lasts for months
• Chief products : CO2, alcohol, & non-volatile acids (give off-flavor)
• Usually accompanied by darkening & crystallization
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.
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
• 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.
•
• 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.
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
HIMA HARIDASAN