The contribution of fatty acids to the composition of the total lipids in juvenile Cape hake fillets - research

Published ArticleDue to the decline in fish stocks more juvenile fish are being caught. The aim of this study was to investigate the contribution of short and medium chain length fatty acids to the composition of the total lipids in juvenile Cape hake fillets and the impact thereof the nutritional value. The fatty acids that most contributed to the total fatty acid composition were palmitic acid (C16:0) (46.52%), docosahexaenoic acid (C22:6) (25.68%) and stearic acid (C18:0) (9.4%). Saturated fatty acid contribution to the total lipid content was found to be higher than reported in literature in other hake species and no eicosapentaenoic acid was detected. Eicosanoic acid, was detected only in the medium sized hake fillets, indicating reduced nutritional value in juvenile hake fillets. The challenges of the fishing industry is thus not only to control the sustainability of fish resources, but also the size of the total allowable catch to ensure the best nutritional level

Microbial levels on the food preparation areas of a typical district hospital in South Africa

Published ArticleThe role of hospital surfaces (including surfaces in food preparation areas) in the transmission of hospital-acquired infections (HAI) has been long recognized; however, evidence regarding this critical information is not well documented. This study was conducted at a typical district hospital in the Free State Province of South Africa. Using swabs, surface samples were collected from nine kitchen areas, quantified and identified using the MALDI-TOF MS and API. Fungal counts (1 x 103 to 2.3 x 105 cfu.cm-2) were higher compared to bacterial counts (1.5 x 103 to 1.1 x 105 cfu.cm-2). A total of 25 bacterial species and 14 fungal species were identified from hospital kitchen surfaces using the MALDI-TOF MS. Candida was the most common fungal genus identified represented by 11 species while Bacillus was the most common bacterial genus isolated represented by 7 species. The presence of species from the genera Acinetobacter, Enterobacter, Pseudomonas and Candida amongst others on kitchen surfaces could have serious consequences as they have been implicated in various studies as probable causes of hospital acquired infections. The study highlights the need to ensure proper cleaning of working surfaces in the kitchen as well as stringent surveillance and monitoring to ensure the minimal contamination of food products prepared for patients

Efficacy of low-pressure foam cleaning compared to conventional cleaning methods in the removal of bacteria from surfaces associated with convenience food

Published ArticleFood borne illnesses and food poisoning are cause for concern globally. The diseases are often caused by food contamination with pathogenic bacteria due largely to poor sanitary habits or storage conditions. Objectives: Prevalence of some bacteria on cleaned and sanitised food contact surfaces from eight convenience food plants in Gauteng (South Africa) was investigated with the view to evaluate the efficacy of the cleaning methods used with such food contact surfaces. Methods: The microbial load of eight convenience food manufacturing plants was determined by sampling stainless steel food contact surfaces after they had been cleaned and sanitised at the end of a day’s shift. Samples were analysed for Total Plate Count (TPC), Escherichia coli, Salmonella species, Staphylococcus aureus and Listeria species. Results: Results showed that 59 % of the total areas sampled for TPC failed to comply with the legal requirements for surfaces, according to the Foodstuffs, Cosmetics and Disinfectants Act ( 0.05) in terms of Listeria species isolates obtained from both cleaning methods. The LPF method proved to be the superior cleaning option for lowering TPC counts. Conclusion: Regardless of cleaning method used, pathogens continued to flourish on various surfaces, including dry stainless steel, posing a contamination hazard for a considerable period depending on the contamination level and type of pathogen. Intensive training for proper chemical usage and strict procedural compliance among workers for efficient cleaning procedures is recommended

Towards the discrimination of milk (origin) applied in cheddar cheese manufacturing through the application of an artificial neural network approach on Lactococcus lactis profiles

Published ArticleAn artificial neural network (ANN) that is able to distinguish between Cheddar cheese produced with milk from mixed and single breed sources was designed. Samples of each batch (4 pure Ayrshire/4 mixed with no Ayrshire milk) were ripened for 92 days and analysed every 14 days. A novel ANN was designed and applied which, based only on Lactococcus lactis counts, provided an acceptable classification of the cheeses. The ANN consisted of a multi-layered network with supervised training arranged in an ordered hierarchy of layers, in which connections were allowed only between nodes in immediately adjacent layers

Investigating the development of acid tolerance in food-borne pathogens Escherichia coli, Salmonella spp., and Pseudomonas aeruginosa and the implication on the susceptibility to organic acids

Published ArticleVarious foodstuffs have a very low pH and bacteria have been reported to survive such products. Acid substances, such as organic acids are common food preservatives. These substances also lower the pH of processed foods. Decontamination with organic acids which could result in the emergence of acid tolerant food-borne pathogens is causing concern. The objectives of the study were to determine the development of acid tolerance in important food-borne pathogenic bacteria, to investigate evolving changes in the phenotypic characteristics as a result this acid tolerance, and to explore the possibility of repercussions in successful food preservation with organic acids. Bacterial strains were screened for acid-tolerance, by determining viable counts immediately before acid challenge and at various times after challenge. Strains were exposed to increasing concentrations of hydrochloric acid, acidic foodstuff and two organic acids (acetic and citric acid). Protein profiles were generated by SDS-PAGE examined for possible modification(s) as a result of acid tolerance development. Susceptibility to seven organic acids levels were scrutinised to evaluate the probability of a correlation between altered antimicrobial activity and acid tolerance. Salmonella enterica sv. Enteritidis ATCC 13076 and Escherichia coli ATCC 25922 indicated rapid development of acid tolerance, after 36h of acid exposure. In Salmonella enterica sv. Typhimurium ATCC 14028, E. coli 0111 and Pseudomonas aeruginosa ATCC 27853 intermediate intrinsic acid tolerance was obvious. On comparing susceptibility of these pathogens to the organic acids, it was demonstrated that pH played a significant role in inhibitory activity, as it is known that these compounds exhibit optimum antimicrobial activity at a lower pH (pH ≤ 5). Further investigations will be conducted to elucidate the two-way role of pH in foodstuff and the addition of an organic acid, in determining if microorganisms are losing their susceptibility for the preservative as a result of sub-optimal pH levels, or if they become acid-tolerant after surviving exposure to organic acids

Bacterial contamination of the hands of food handlers as indicator of hand washing efficacy in some convenient food industries

Background and Objectives: Hands of ready-to-eat food service employees have been shown to be vectors in the spread of foodborne disease, mainly because of poor personal hygiene and accounting for approximately 97% of food borne illnesses in food service establishments and homes. Our objective was to evaluate the efficacy of hand washing practices and sanitation before commencing work among food handlers in the convenient food industry in Gauteng, South Africa. Methods: A total of 230 samples were collected, involving 100% of the food handlers, in 8 selected convenient food outlets with their main focus on preparing ready-to-eat foods. The workers’ cleaned and disinfected dominant hands were sampled for Total Plate Count (TPC), Staphylococcus aureus and Escherichia coli. Bacteria were isolated and counted using standard methods. Results: The highest bacterial count from the hand samples was 7.4 x 103 cfu.cm-2 and the lowest showed no detectable growth. Although hands with a count of 0 cfu.cm-2 were found in all of the plants, the results indicated that all the plants exceeded the legal limit for food surfaces or hands of < 100 cfu.cm-2 when the average bacterial counts on hands were compared. Sixty percent of the TPC analysed exceeded the legal limit and only 18% of the food handlers had no bacteria detectable on their hands. One sample tested positive for E. coli and S. aureus could not be detected on the hands of any of the food handlers. Conclusion: The study revealed that hand hygiene is unsatisfactory and may have serious implications for public health due to contamination of food from food handlers’ hands. This therefore underlined the importance of further training to improve food handlers’ knowledge of good hand washing practices