Restaurant Syndrome’. The typical scenario is where rice is prepared in
bulk, in advance. Spores, commonly those of the more heat-resistant
serotype 1, survive precooking to germinate, grow and produce the
emetic toxin in the product during storage. This would be prevented
by chilling to below 8 1 C, but the rate of cooling in the centre of a bulk of
cooked rice, even if transferred to chill storage, can be slow enough for
growth and toxin production to occur. Reheating the rice prior to serving
will not inactivate the emetic toxin and render the product safe.
A wider range of foods have been implicated with the diarrhoeal
syndrome including meat products, soups, vegetables, puddings and
sauces. Dried herbs and spices used in food preparation can be an
important source ofB. cereusand this has often been cited as a reason for
a relatively high incidence ofB. cereusfood poisoning in Hungary, where
between 1960 and 1968 it was the third most common cause of food
poisoning accounting for 15.2% of persons affected. More recent figures
suggest that its relative importance has declined somewhat but whether
this is due to changes in culinary practices, improvements in hygiene,
decreased contamination of spices or a statistical artefact is not known.
Meat pies and pasties are common vehicles for the other food-
poisoning bacilli along with a range of processed meats and meat and
rice dishes. Baked goods such as bread and crumpets have been involved
in a number ofB. subtilisoutbreaks. AlthoughB. subtilisis responsible
for the defect known as ropey bread where spores surviving baking
degrade the loaf ’s internal structure and produce a sticky slime, this does
not always prevent people from eating it. In 1988, a bakery in the Isle of
Man omitted propionate from their bread in order to claim for it the
virtue of being free from artificial preservatives and thereby more
healthy. As a result, nine people developed nausea, vomiting, diarrhoea,
headache and chills 10 min after consuming ropey bread containing more
than 10^8 organisms gm^1.
7.3 Brucella
7.3.1 Introduction
The genusBrucellais named after Sir David Bruce who in 1887 recognized
it as the causative organism of undulant fever (brucellosis, Malta fever,
Mediterranean fever). Each of the four species that are human pathogens
is associated with a particular animal host,B. abortus(cattle),B. melitensis
(sheep and goats),B. suis(pigs), andB. canis(dogs) (Table 7.3). Brucellosis
is principally contracted from close association with infected animals and
is an occupational disease of farmers, herdsmen, veterinarians and slaugh-
terhouse workers. It can also be contracted by consumption of milk or
milk products from an infected animal, although the risk is lower. The
190 Bacterial Agents of Foodborne Illness