Alan H. Varnam

Enterotoxins and emetic toxins production by Bacillus cereus and other species of Bacillus isolated from Soumbala and Bikalga, African alkaline fermented food condiments

The ability of various species of Bacillus from fermented seeds of Parkia biglobosa known as African locust bean (Soumbala) and fermented seeds of Hibiscus sabdariffa (Bikalga) was investigated. The study included screening of the isolates by haemolysis on blood agar, detection of toxins in broth and during the fermentation of African locust bean using the Bacillus cereus Enterotoxin Reverse Passive Latex Agglutination test kit (BCET-RPLA) and the Bacillus Diarrhoeal Enterotoxin Visual Immunoassay (BDEVIA). Detection of genes encoding cytotoxin K (CytK), haemolysin BL (Hbl A, Hbl C, Hbl D), non-hemolytic enterotoxin (NheA, NheB, NheC) and EM1 specific of emetic toxin producers was also investigated using PCR with single pair and multiplex primers. Of 41 isolates, 29 Bacillus belonging to the species of B. cereus, Bacillus subtilis, Bacillus licheniformis and Bacillus pumilus showed haemolysis on blood agar. Using RPLA, enterotoxin production was detected for three isolates of B. cereus in broth and all B. cereus (9) in fermented seeds. Using BDEVIA, enterotoxin production was detected in broth as well as in fermented seeds for all B. cereus isolates. None of the isolates belonging to the other Bacillus species was able to produce enterotoxins either by RPLA or BDEVIA. Nhe genes were detected in all B. cereus while Hbl and CytK genes were detected respectively in five and six B. cereus strains. A weak presence of Hbl (A, D) and CytK genes was detected in two isolates of B. subtilis and one of B. licheniformis but results were inconsistent, especially for Hbl genes. The emetic specific gene fragment EM1 was not detected in any of the isolates studied.

Identification of Bacillus spp. from Bikalga, fermented seeds of Hibiscus sabdariffa: phenotypic and genotypic characterization

Aims:  To identify Bacillus spp. responsible of the fermentation of Hibiscus sabdariffa for production of Bikalga, an alkaline fermented food used as a condiment in Burkina Faso.

Concentrated and Dried Milk Products

After reading this chapter you should understand The differences between the various types of concentrated milk products The various means by which milk may be concentrated The design of commonly used equipment The drying of milk The design of spray dryers The relationship between the processing of dried milk and its end-uses The major control points The nature of chemical changes associated with concentration, drying and subsequent storage Microbiological hazards and patterns of spoilage

Dairy Protein Products

After reading this chapter you should understand The nature of the different types of dairy protein products The processing used in their preparation The modification and fractionation of dairy protein products The functional properties of dairy protein products and their use as ingredients The nutritional properties of dairy protein products Microbiological considerations associated with production of dairy protein products

Liquid Milk and Liquid Milk Products

After reading this chapter you should understand The difference between the various types of liquid milks The key roles of processing The basic technology of processing The major control points The nutritional effects of milk processing The nature of chemical changes associated with processing and subsequent storage Microbiological hazards and patterns of spoilage

Butter, Margarine and Spreads

After reading this chapter you should understand The nature of butter, margarine and spreads The ingredients used in their manufacture The technology of their manufacture The major control points The technology and uses of industrial dairy fats The basic chemistry of procedures for modifying fats The physico-chemical structure of butter, margarine and spreads Microbiological hazards and patterns of spoilage

Cocoa, Drinking Chocolate and Related Beverages

Theobroma cacao, the cocoa tree, was first cultivated in Central America by the Mayas of Yucatan and the Aztecs of Mexico. The Aztecs believed the tree to be of divine origin, a belief reflected in the appellation Theobroma — ‘Food of the Gods’ — given to the genus by Linnaeus. A preparation, chocolatl, made by mixing roasted ground cocoa nibs with water, maize and spice, was consumed as a luxury in the court of the Aztec emperor Montezuma and was widely thought to have aphrodisiac properties.

Alcoholic Beverages: III. Distilled Spirits

Distillation is one of the earliest examples of chemical technology. The process was known in China many hundreds of years before the birth of Christ and the first distilled beverage is believed to have been made from rice wine about 800 BC. The secret of distillation remained in China until the first few years AD, when the process was studied in Egypt. The art was learnt by Arabic chemists, who developed the first truly efficient still, the alembic. A direct descendent of the alembic,the pot still is in use today in the distillation of several spirits, including Scotch whisky.

Alcoholic Beverages: II. Wines and Related Drinks

Wine making is an important economic activity, not only in the traditional countries of the ‘old world’ such as France and Germany, but also in ‘new world’ countries such as Australia, the US and Argentina. Wine production is also increasing in the UK.

Alcoholic Beverages: I. Beer

The production, and consumption, of alcoholic beverages is one of man’s oldest activities. Today brewing, wine making and distilling are of major commercial importance in many non-Islamic countries and, through taxation, can be an important source of government revenue. At the same time it must be recognized that excess consumption of alcohol leads to serious social and medical problems for individuals as well as loss to the national economy through loss of productivity, cost of medical treatment, etc.