food micro molds

what is a mold

a type of fungus that can grow on the surface of foods and cause food spoilage and decomposition

molds are a member of what kingdom

fungus

grow in form of multicellular filaments called

hyphae

hyphae intertwine to form ?

mycelium and are visible to naked eye

molds spread through

spores

mold growth and reproduction cycle

• spore lands

• germination

• hyphal growth

• mycelium formation

• sporulation

spore lands

a spore lands on a suitable surface to start the mold growth and reproduction cycle

germination

2, the spore absorbs moisture and germinates

hyphal growth

3, hyphae elongate and branch, increasing the network

mycelium formation

4, hyphae interweave to form a mycelium that colonizes the substrate

sporulation

5, arial hyphae develop spore bearing structures that produce and release spores

hyphae

thread like filaments that make up the vegetative body of molds

septate hyphae

divded by cross walls

non septate (coenocytic) hyphae

no cross walls, with multiple nuclei in a continuous cytoplasm

mycelium

mass of interwoven hyphae that form the main body of the mold

vegetative mycelium

found within or on the substrate

areial mycelium

grows above the surface

sporangia

structures where spores are produced

typically, spherical or oval, found at the tip of the hyphae

conidiophores

specialized stalks that bear conidia the asexual spores of certain spores

conidia

non motile, asexual spores produced externally on coidiophores in chains or clusters , responsible for the dispersal of the mold

sclerotia

compact, hardened masses of hyphae that molds can form under adverse environmental conditions

zygospores

thick- walled, sexually produced spores formed when two compatible hyphae fuse

chlamydospores

thick walled, asexual spores formed from hyphal cells under stressful conditions

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issues with molds in foods

• food spoilage

• mycotoxins

mycotoxins

toxin produced by certain species of molds that can contaminate food, animal feedm and agricultural products

• serious health risks when ingested or inhaled or absorbed through the skin

how are mycotoxins produced

as secondary metabolites, as they are not essential for the growth but may provide a competitive advantage in certain environments

why care about mycotoxins?

they are heat stable- cooking and processing does not destroy them

molds can grow before, during and after harvest, and during storage

regulatory oversight of mycotoxins

FDA monitors the food supply for mycotoxins by collecting and analyzing samples of domestic and imported foods

common molds found in food

Aspergillus

Penicillium

Rhizopus

Fusarium

Aspergillus

common genus of fungi, consisting of over 300 species

filamentous fungi characterized by branched, septate hyphae and abundant asexual spores

some species produce mycotoxins

some are beneficial in food fermentation

Aspergillus reproduction

produce asexual spores

common foods of Aspergillus

fruits, grains, breads, meat, milk, cheese

Aspergillus structure

penicillium

genus of filamentous fungi characterized by branched septate hyphae

certain species produce penicillin

beneficial species are widley used in the production of blue cheese and soft cheeses

penicillium reproduction

produce chains of asexual spores on brush like conidiophores

penicillium common foods

production- Roquefort, Gorgonzola, Camembert, Brie

spoilage- fruits, breads, dairy products

penicillium structure

Rhizopus

often called black bread mold

filamentous fungus characterized by broad coenocytic hyphae

common cause of soft rot in fruits and vegtables

Rhizopus reproduction

produces asexual spores enclosed within spherical sporangia borne at the tips of specialized hyphae called sporangiophores

under favorable conditions some can reproduce sexually

Rhizopus common foods

production- teph, ragi

spoilage- fruits, veggies, grains

Rhizopus structure

Fusarium

a genus of filamentous fungi characterized by septate hyphae and distinctive curved or canoe shaped macrocoidia

common in agriculture environments and responsible for numerous plant diseases

Fusarium reproduction

produces asexual spores including macroconidia and micronidia

Fusarium appearance

•Colonies are often cottony or woolly and may appear white, pink, reddish, or purple, depending on the species.

fusarium common foods

foods- grains

issues- mycotoxins, fusarium wilt, fusarium head blight, root rot, seedling blight

fusarium structure