The fate of spoilage and pathogenic bacteria in fermented sauce-based salads

“…The bacteria load of raw and cooked food samples examined showed that none of the food samples were sterile. The food samples were found to consist of different group of bacteria and this agreed with the work of Bonestroo et al (1993) who reported that many spoilage and pathogenic bacteria were isolated from raw vegetable salads and ready-to-eat-food. It was also noted that contamination of the raw vegetables can occur in the field or during post harvest handling when contamination of cooked food might be due to inadequate cooking or improper storage of food as well as poor sanitary condition in food preparation.…”

Section: Discussionsupporting

confidence: 88%

Toxin production in food as influenced by pH, thermal treatment and chemical preservatives

Oladipo¹,

Adebiyi²,

Ay³

2008

Afr. J. Biotechnol.

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Sixteen foods borne bacteria were isolated from raw food samples including okro, carrot, spinach, pepper, tomato, onion and cooked food samples (rice, yam, beans, meat and plantain). The isolates were characterized and identified as Bacillus brevis, Bacillus congulans, Bacillus polymyxa, Bacillus lentus, Bacillus megaterium, Bacillus subtilis, Acinetobacter spp., Citrobacter freundii, Klebsiella aerogenes, Streptococcus agalactiae, Alcaligenes spp., Corynebacterium spp., Enterobacter aerogenes, Enterobacter spp. and Staphylococcus epidermidis. These isolates were screened on egg yolk agar for toxigenic properties and thirteen of the sixteen were positive for toxin production while three were negative. Six out of the thirteen toxigenic bacterial were selected for further work. These were; E. coli, K. aerogenes, C. freundii, B. polymyxa, S. epidermidis and E. aerogenes. The effect of pH, thermal treatment and chemical preservatives on the growth rate and toxin elaboration of E. coli, K. aerogenes, C. freundii, B. polymyxa, S. epidermidis and E. aerogenes was studied. It was observed that E. coli had no viable growth until 48 h of incubation, while the other five isolates had visible growth right from the 24 h of incubation. Also E. coli did not produce toxin until the 96 th hour of incubation; K. aerogenes and E. aerogenes were able to produce toxin at 24 h of incubation, while C. freundii, B. polymyxa and S. epidermidis produced toxin at 48 h of incubation. Also, 44°C was not suitable for toxin production. pH 3 and 5 were less favorable for toxin production despite the fact that isolates were able to grow at different temperature and pH ranges. The isolate were more sensitive to sodium metabisulfite than benzoic acid. Also, E. coli and K. aerogenes were able to elaborate toxin in their dormant state with 750 mg of sodium metabisulfite.

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Section: Discussionmentioning

confidence: 99%

“…Another study showed that S. aureus was present on skin of animals such as chickens contaminating about 24% of chicken samples examined [36]. Rapid food cooling, proper storage conditions and hygienic care reduce S. aureus contaminations [37].Most of the enterotoxin producers were isolated mainly from chicken pastries, followed by egg sandwiches. Although most of the isolates were from nasal swabs, the isolates from this source were the least SE producers.…”

mentioning

confidence: 99%

Staphylococcus aureus Contamination during Food Preparation, Processing and Handling

Al-Bahry¹,

Mahmoud²,

Al-Musharafi³

et al. 2014

IJCEA

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Abstract-Throughout the world, food processing and handling is a major problem leading to food poisoning and infection. A total of 480 samples was analyzed for Staphylococcus aureus contamination which resulted from food processing. Most of the isolates were taken from food-handlers using nasal swabs. The most contaminated food was chicken pastries, followed by egg sandwiches and spring rolls. Isolates from all samples produced virulence factors hemolysin, coagulase, DNase and enterotoxins. Five different enterotoxins (SEs) were isolated and identified from different samples. The detected SEs are SEA to SEE. Most the isolates secreted SEA followed by SEB. The strains were multiple-resistant to several antibiotics. Ampicillin and penicillin were the most resisted antibiotics. The value of this investigation is to generate awareness about the dangers of food processing and handling leading to infections by foodborne microbes which constitute a potential health risk for the consumers.Index Terms-Staphylococcus aureus, contamination, food products, food handlers. I. INTRODUCTIONFood processing is an important industry worldwide. One of the major problems threatening food industry is the contamination with foodborne microbes of human origin resulting from improper handling and processing. Microbial contamination reduces shelf life and food quality leading to food infection and poisoning outbreaks, some of which are life threatening. Continuous monitoring of food processing is essential to avoid potential health problems.Staphylococcus aureus is one of the major foodborne pathogens, frequently causing diseases globally as a result of food ingestion contaminated with staphylococcal toxin [1].S. aureus is characterized by its ability to produce enterotoxins [2], which are considered to be the main causative agents of staphylococcal food poisoning [1]. S. aureus are commonly found on the skin of mammals, birds and fomites [2]. Humans are considered to be the major source of staphylococcal food poisoning [3]. S. aureus is found in nasal passages, throat, hair and skin of carriers [2]. Food is usually contaminated from nasal secretions, sneezing, coughing and direct hand contact of infected carriers [4], [5].Three categories of S. aureus carriers have been Manuscript received November 9, 2013; revised February 21, 2014 recognized: persistent, intermittent (occasional) and never-carriers. Persistent carriers are infected with the same staphylococcal strain for months or even years. It was reported that 20% -35% are persistent carriers. In addition, intermittent carriers represent 40% -70%, while never-carriers are uninfected representing 10% -40% of the population [6], [7].S. aureus secretes several virulence factors and extracellular toxins of protein origin which contributes to the pathogenicity. It is the only species that produces beta hemolysin which lyse red blood cells at cold temperature [6].Unlike other foodborne illnesses, staphylococcal food poisoning occurs shortly after, 30 min to 8 hrs, food ingestion contamin...

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The fate of spoilage and pathogenic bacteria in fermented sauce-based salads

Cited by 13 publications

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Inhibition of Bacillus cereus by lactic acid bacteria starter cultures in rice fermentation

Inhibition of Bacillus cereus by lactic acid bacteria starter cultures in rice fermentation

Toxin production in food as influenced by pH, thermal treatment and chemical preservatives

Staphylococcus aureus Contamination during Food Preparation, Processing and Handling

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