20
Figure 2. Pathogenesis of salmonellosis.
Source: Gianella 1979
Two types of salmonellosis result because of consuming foods contaminated with Salmonella
bacteria: non-typhoidal and typhoidal salmonellosis. Almost all serovars are pathogenic and belong to the non-typhoidal causing salmonellosis, in the form of food
poisoning with no enteric fever, except the serovars S.Typhi, S.Paratyphi A, S. Paratyphi B, and S.Paratyphi C. These three serovars bring about the commonly known typhoid
and paratyphoid fevers in humans. S.Typhi initiates typhoid, whilst S.Paratyphi A, B, and C initiate paratyphoid fever; Paratyphoid fever is a systemic disease, caused by
having symptoms similar to those of typhoid fever, but they are milder and the case fatality rate is much lower Maskalyk 2003.
2.1.4 Occurrences associated with foods
Salmonellosis outbreaks have occurred from a variety of foods including poultry, meats, eggs, milk products, fruit juice, fish, shrimp, frog legs, yeast, coconut, sauces and
salad dressing, cake mixes, breakfast cereal, cream-filled desserts and toppings, dried gelatin, peanut butter, cocoa, chocolate, and dried spices. The incidence of Salmonella is
much higher in raw agricultural products e.g. raw eggs, or uncooked poultry or meat than in cooked or processed food products. However, Salmonella can occur in other
foods as a result of cross-contamination with raw foods, or from contamination from humans, animals, birds, or reptiles. Furthermore, due to the microorganisms ability to
survive in wide range of environments, Salmonella has been found in dry and dehydrated foods e.g. cocoa, chocolate, dry milk, spices, and cereal products and in
more acid food products e.g. non-pasteurized orange juice. Thus, preventative
21 measures are extremely important at all food handling and processing steps Schneider
et al 2003.
Several research studies carried out in Indonesia have found Salmonella in foods. Rusyanto 2005 isolated Salmonella from shrimp samples as well as from the sediments
and water in which the shrimps were obtained from. Serological tests confirmed several serovars including S. Lexintgon, S. Kirkee, S. Hadar, S. Infantis, and S. Paratyhi B;
amongst them S. Paratyphi B causes typhoidal salmonellosis whilst the others cause non-typhoidal salmonellosis. Agustin 2004 isolated S. Weltevreden from fresh lettuce
sold in traditional markets around Bogor area. Out of 50 samples analyzed, 2 samples were serologically confirmed to contain Salmonella Weltevreden.
Other studies by Ruslan 2003 and Susilawati 2002 also detected Salmonella in vegetables, however no serological tests was done to identify the serovars present.
Susilawati 2002 studied bean sprouts, cabbages, carrots and long green beans; these fresh vegetables were from the farms and traditional markets. The study found that
almost 80 of the raw and fresh vegetables were Salmonella positive. The contamination of these vegetables were thought to have been from contaminated
irrigation water, washing water and other fecal contamination most probably from fertilizers.
There have been and still will be cases, and outbreaks as a result of Salmonella species inflictions due to consuming contaminated foods, or being passed on from
infected persons or animals; a few outbreaks and cases are reported in this paper. The latest of outbreaks due to one of the strains of Salmonella bacteria S. Typhimurium
was linked to peanut butter in the United States CDC 2009. Another outbreak reported in 2008 by Food and Drug Administration USA
that 145 to 150 people in 16 states were sickened by salmonellosis which was linked to tomatoes being the vegetable containing the pathogen. It was caused by a rare strain of
Salmonella Saintpaul; 25 people were hospitalized but no deaths reported Weise 2008.
Also in USA the same year 2008 an outbreak reported to have been caused by S. Agona was linked to cereal from Malt-O-Meal unsweetened Puffed Rice Cereals and
unsweetened Puffed Wheat Cereals. Fifteen states identified 28 ill persons infected with same genetic fingerprint of Salmonella Agona. Inflicted persons with the outbreak strain
had been identified from Colorado 1, Delaware 2, Illinois 1, Maine 4,
22 Massachusetts 2, Michigan 1, Minnesota 1, North Dakota 1, New Hampshire 2,
New Jersey 5, New York 3, Ohio 1, Pennsylvania 2, Rhode Island 1, and Vermont 1 FDA 2008.
Outbreaks were also associated with alfalfa sprouts in Norway, Denmark and Finland from July to October 2007. Nineteen cases had been reported in Norway,
nineteen in Denmark, and seven in Finland. The patient s ages ranged from 18 to 83 years median age 34 years. Thirty-five cases were female and 10 male. The serovar
isolated was S.Weltevreden Emberland et al 2007. In August 1999 in Okinawa, 30 persons suspected of food poisoning visited the
hospital having major symptoms included diarrhea 96, average 21 times, fever 85, average 39
° C, abdominal pain 86, headache 58, nausea 28 and vomiting
25. Two days earlier on they had participated in a party and consumed goat meat and soup. Microbial tests conducted found that Salmonella Weltevreden was present in
stools of 4 of the patients, raw goat meat, and goat meat soup. Meat and environmental samples at the slaughter house also yielded where the meat was from also yielded S.
Weltevreden Kudaka 2000. In Bangkok, Thailand, from 1993 to 2002, a total of 70, 235 isolates received
were confirmed as S. enterica and serotyped by the Salmonella and Shigella diagnostic laboratories. Serotyping was done for 44,087 Salmonella isolates from humans and
26,148 from other sources from 1993 through 2002. Samples were obtained from humans, ducks, chicken, seafood, other food products, and water for all 10 years. Table
2.0 shows the species that were isolated. It can be noted that S. Weltevreden was present in all the samples except in frozen chicken; S. Agona was present in all the samples
except in frozen seafoods Bangtrakulnonth et al 2003.
23
Table 2.0 Distribution of the 10 most common Salmonella serovars from the
different reservoirs, Thailand
a
Reservoir and no. of isolates in brackets
Salmonella serovar Humans
Frozen chicken
Frozen seafood
Frozen duck
Other food products
Water Weltevreden
5,491 12.5 —
265 26.3 320
12.0 457
6.6 143
14.5 Enteritidis
5,010 11.4
2,901 19.9
14 1.4
309 4.5 22
2.2 Anatum
3,263 7.4
423 2.9 20
2.0 1,177
17.0 113 11.5
Derby 2,889
6.6 20
2.0 370
5.3 71 7.2
1, 4,
5, 12:i:-ssp.I
2,804 6.4
Typhimurium 2,322
5.3 12
1.2 198
2.9 Rissen
2,319 5.3
21 2.1
712 10.3 93
9.5 Stanley
1,688 3.8
20 2.0 279
10.4 Panama
1,474 3.3
41 1.5 254
3.7 47 4.8
Agona 1,096
2.7 452
3.1 80
3.0 273 3.9 39
4.0 Paratyphi B var
Java 1037
7.1 Hadar
1,357 9.3 21
2.1 263 9.9 439
6.3 Virchow
863 5.9
249 3.6 27
2.7 Schwarzengrund
565 3.9
Emek 359
2.5 Blockley
676 4.6
Amsterdam 368
2.5 103
3.9 Seftenberg
49 4.9 86
3.2 Lexington
47 4.7
35 3.6
Newport 100
3.7 Tennessee
77 2.9
Chester 171
6.4 London
22 2.2
Other 15,824
35.9 5,558 38.2
518 51.4 1,150
43.1 2,490
35.9 372
37.8 Total
44,087 14,559 1,007 2,670 6,928 984
a
, not among the top 10 serovars. Source: Bangtrakulnonth et al 2003
24 A few years back, a Salmonella outbreak in England and Wales, which
affected 37 people, many of which were children, was said to be caused by Cadbury chocolates that were contaminated with Salmonella serotype Montevideo
Times online, 2006. As a consequence, the Food Standards Agency FSA ordered Cadbury s to remove 250 tons of chocolates from shop shelves and warehouses
Daily Mail, 2006. It is quite clear that such actions recall and disposal of chocolates would have significant economic consequences.
One other outbreak which affected more than 350 people in Britain, occurred in 2004, and was linked to Salmonella serotype Newport contaminated lettuce from fast
food and catering establishments Daily Mail, 2004. These and other cases of salmonellosis have enforced a more stringent attitude towards food products. Regulation
tests conducted during March 2005 to July 2006 by the FSA found that one out of every 30 boxes of eggs from those imported into the UK, tested positive for
Salmonella contamination ElAmin, 2006c. The highest prevalence of
contaminated eggs was found to originate from Spain, with S. enteritidis being the most commonly isolated strain. The European Commission prompted efforts to
minimize contamination by Salmonella and other foodborne pathogens. These included compulsory vaccination of flocks in countries such as Spain and France, which
have the highest prevalence of contaminated birds. Secondly trade bans of eggs with high levels of Salmonella were also proposed. Such actions have been effective in
reducing the number of cases of salmonellosis in the 25 EU states, which was reported at 192,703 cases during 2004 ElAmin, 2006c.
A wide variety of foods have been implicated in outbreaks of illness caused by many different serotypes of Salmonella: raw meats, poultry, eggs, milk and dairy
products, fish, shrimp, frog legs, yeast, coconut, sauces and salad dressing, cake mixes, cream-filled desserts and toppings, dried gelatine, peanut butter, cocoa, and chocolate.
Various Salmonella serotypes have long been isolated from the outside of eggshells. The present situation with S. Enteritidis is complicated by the presence of the organism
inside the egg, in the yolk. This and other information strongly suggest vertical transmission, i.e., deposition of the organism in the yolk by an infected layer hen prior to
shell deposition. Foods other than eggs have also caused outbreaks of S. Enteritidis disease. Salmonella still is the most frequently recorded pathogen in the production
25 chain of food of animal origin. At present the predominant serotypes are S. Enteritidis
and S. Typhimurium. This is true especially considering the most important meats from pig and poultry. In areas such as Scandinavia measures against this pathogen have been
traditionally more thoroughly endeavored, finally resulting in a lower prevalence of Salmonella
in these 122 countries compared to Continental Europe .
Whatever the Salmonella
serotype, effective controls for minimizingeliminating the hazard of Salmonella
from foods involve control of the following steps: raw materials, personal and environmental hygiene, process conditions, post-process contamination, retail and
catering practices, consumer handling. Other studies have shown the occurrence of Salmonella species in foods due to
improper hygiene and sanitation processes. Salmonella serotype Hartford and Salmonella
serotype Gaminara were isolated from unpasteurized orange juice Cook et al
1998. Regardless of the environmental source and means of contamination, once Salmonella
was introduced into the processing plant, inadequate cleaning and sanitization of processing equipment probably contributed to production of
contaminated juice. The presence of a specific fecal indicator organism in all samples of orange juice tested indicates improper sanitation in the processing plant. The
identification of the same subtype of a rare Salmonella serotype Gaminara in juice produced during a 3-month span May- July suggests that there was an ongoing source
of Salmonella within the plant Cook et al 1998. Ditjen POM Pengawasan Obat dan Makanan, a body that enforces food and
medicinal drug safety in Indonesia set the standard RI. No. 03726BSLV1 for foods to be free from Salmonella zero Salmonella in 25g of samples analyzed. This is also
the same requirement by USFDA United States Food and Drug Administration USFDACFSAN 2007, that all foods analyzed 25g samples should be free from
Salmonella .
2.2 Coliforms 2.2.1 Taxonomy and characteristics
