Food Microbiology - Algae

Algae

are aquatic, photosynthetic protists that can be found in both fresh and marine waters.

70%

percentage of oxygen that algae contributes to the Earth’s atmosphere

• Unicellular or multicellular

• Lack of complex structures and vascular tissues

• Primarily found in aquatic environments

Difference of algae from plants

Alexandrium spp.

genus of bloom-forming marine dinoflagellates; found worldwide, typically sub-polar, temperate and tropical marine water.

Alexandrium spp. cysts

are known to be spherical or ellipsoidal with rounded ends along with minor distinctions depending on the species

Alexandirum spp. swimming cells

are roughly spherical with two flagella; either individual cells or in chains characterized by its reddish-brown color

Saxitoxins

Alexandrium spp. produces this most potent type of paralytic shellfish toxins

Paralytic shellfish toxins

ingestion of this toxin causes nausea, vomiting, numbness and respiratory paralysis and death; cooking the shellfish does not eliminate the risk of this illness

Alexandrium tamarense

Alexandrium catanella

Alexandrium monilatum

Gambierdiscus toxicus

non-bloom forming dinoflagellates that are primarily found in warm, temperate environments and are observed to be epiphytes that grows along seaweeds and corals.

Gambierdiscus toxicus

Anteroposteriorly compressed ranging from 40-140 microns that contains yellow and or brown chloroplasts

Ciguatoxiuns

toxins produced by Gambierdiscus toxicus that are heat-stable neurotoxins that can cause ciguatera poisoning

Ciguatera poisoning

toxin produced by Gambierdiscus toxicus that affects the voltage-gated sodium and potassium channels

Maitotoxin

toxin produced by Gambierdiscus toxicus that are considered to be the most potent marine toxins; it affects the calcium channels of the cells

Gambierol

Polycyclic ether toxin that can contribute to ciguatera poisoning that affects the potassium channels

Ciguatera poisoning

most common non-bacterial seafood-borne illness worldwide;

Occurs through eating fish that consumed the algae ; toxins are heat stable

Ciguatera poisoning

a patient may feel these symptoms when experiencing this illness: nausea, vomiting, diarrhea, dehydration, pruritis, numbness, tingling sensations, low blood pressure, and paralysis

Karenia brevis

bloom-forming dinoflagellates that are known to cause red tides or HABs that are mostly found in shorelines; they do not have a specific season

Karena brevis

are known for their flattened clover leaf shape and lack of cellulose thecae layer, they are delicate and lyse easily

Brevetoxins (PbTXs)

are undetectable and preservation techniques are not applicable to remove risk of illness; they affect the polyether sodium channel neurotoxins.

Neurotoxic shellfish poisoning

symptoms of this illness includes nausea, vomiting, diarrhea, paresthesia, paradoxical temperature sensations, and bradycardia

Pyrodinium bahamense

bloom-forming dinoflagellates that causes red tides; they are mainly found in warm, tropical and temperate waters; caused the first recorded red tide in the Philippines

1983; Samar and Leyte

The first red tide was recorded in this year and location

Pyrodinium bahamese

Polyhedral and irregularly spherical; Has a thecae layer; Either present as individual cells or in chains

Paralytic shellfish poisoning

illness caused by Pyrodinium bahamense due to their production og saxitoxins

Pyrodinium bahamense

Leading cause of PSP fatalities in various countries such as the Philippines and Mexico

Gymnodium catenatum

bloom-forming dinoflagellates that contributes to the occurence of red tides worldwide ; they have received much attention after causing a massive bloom which spanned across 200km of the shoreline of Mexico in April 1979

Gymnodinium catenatum

Cells are found to be spherical to squarish in shape; Often seen in long chains of 32 to 64 cells; Lacks a thecae layer

saxitoxins, ganyautoxins and hydrobenzoyl toxins

toxins of Gymnodium catenatum that are known as paralytic shellfish toxins

Dinophysis spp.

planktonic dinoflagellates that are the major origin of diarrhetic shellfish poisoning

Okadaic acids

lipid soluble toxins that causes diarrhetic shellfish poisoning this can be produced by Dinophysis spp.

0.2g

shellfish containing more than this amount of DSP toxins are considered unfit for consumption

Singapore and Philippines

muscles with DSP above human safety levels are confirmed in these countries

Diarrhetic shellfish poisoning

the symptoms of this illness includes gastrointestinal effects such as severe diarrhea, nausea, vomiting and abdominal pain

Pseudo-nitzschia spp.

are widely distributed pennate diatoms that have diverse temperature ranges, they can also occupy various habitats from open oceans to coastal waters.

Pseudo-nitzschia spp.

blooms are triggered by increased nutrients, high light levels adn warm seawater temperatures

US West Coast

occurence of toxigenic Pseudo-nitzschia spp. are greatest in this area

Vietnam, Korea, Japan, China and Russia

Areas where Pseudo-nitzschia spp. are recorded but with no poisoning recorded

Pseudo-nitzschia spp.

are green, phothosynthetic cells with bilaterl symmetry; frustules they create long chains that glide through the waters as a unit; have quiscent phase

frustules

Pseudo-nitzschia spp. have this silica walls called…

domoic acid

are potent neurotoxins that are produced by Pseudo-nitzschia spp. which accumulate in marine organisms such as shellfish, finfish and zooplankton ; this impacts nervous system of human and wildlife consumers

Amnesic shellfish poisoning

causes short term memory loss, gastrointestinal distress and neurological symptoms caused by the consumption of domoic acids produced by Pseudo-nitzschia spp.

Caulerpa spp.

belongs to a chlorophyta group, some spp. can be nontoxic and edible; they can growin rocks, sands, muds, and undergoes rapid proliferation

Caulerpa lentillifera and Caulerpa racemosa

are edible species of Caulerpa

Caulerpa toxifolia

are known to be killer alga

Caulerpa prolifera

is a toxic spp. of Caulerpa.

1984, Mediterranean

is the year Caulerpa taxifolia was first documented in this area as invasive.

Caulerpa spp.

Single cell thallus that is multinucleated; coenocytic morphology and consists of a creeping rhizome with rhizoids and photosynthetic branches.

Caulerpenyne

has shown antitumoral properties but is neurotoxic, affecting human cells like melanocytes, keratinocytes and fibroblasts at higher concentrations; it disrupts the calcium storage of cells that impacts DNA synthesis.

Caulerpicin

causes numbness and cold sensations in mouth fingers and toes

Caulerpa racemosa

are Caulerpa spp. that are able to produce Caulerpicin

Ciguatera poisoning

caused by consumption of Caulerpa-eating fish like Sarpa salpa (Mediterranean sea bream)

Acanthaphora specifera

is a species of red algae that is part of the Rodomelaceae family; they are widely distributed in Guam, Houtman, Abrolhos, and Hawaii

beta carotene, antheranxathin and carrageenan

Acanthophora specifera is a good source of this

2002 and 2003

years when Acathaphora specifera caused an outbreak in the Philippines that led to 33 deaths

Polycarvenoside A

a glycosidic toxin, it can cause infection via direct human consumption of contaminated seaweed or seafood contaminated with it.

Polycarvenoside

contains aglycone and polyene side chain that can cause epithelial damage and nutrient absorption impairment

Gracilaria verrucosa

belongs to Rhodophyta and Gracilariaceae family; it can grow in muddy/sandy bottoms, eulitoral and sublittoral zones, and forms large beds in calm coastal waters.

Asia, South America, Africa

Gracilaria verrucosa are cultivated in these continents

Gracilaria verrucosa

cylindricla thallys, and bushy branched appearance, elevated cystocarps with colors ranging from purplish brown to dark brown red.

Prostanoids

lipids contained by Gracilaria verrucosa that can cause nausea, diarrhea, vomiting, hypotension and bleeding that are rapid onset in humans

Ingestion

MOT of Gracilaria verrucosa

G. verrucosa and G. chorda

lead to deaths in Japan in years 1980, 1982, and 1993