Infant foods as a potential source of diarrhoeal illness in rural West Africa.

It is common practice in rural areas of The Gambia to prepare infant foods in quantities which are sufficient to meet the needs of the day rather than one meal. These are then stored at ambient temperatures for periods up to 12 hours for feeding to the child on demand. The total viable counts and levels of Bacillus cereus, Clostridium welchii, Staphylococcus aureus and Escherichia coli were determined in 294 infant foods samples from nought to eight hours after preparation. The presence of Salmonella was determined in 10 g samples of food. In the first hour after preparation the proportion of foods dangerously contaminated was high during the rainsy season, significantly more so than during the dry season. Foods not consumed fresh were very often hazardous and almost always so after 8 hours. This problem may be a causal factor in weanling diarrhoea which also shows marked seasonal variation in prevalence.

The survival and recovery of Salmonella typhimurium phage type U285 in frozen meats and tryptone soya yeast extract broth.

The survival of S. typhimurium U285 was studied in cooked minced beef, sausage mixture and tryptone soya yeast extract (TSY) broth stored at freezer temperatures (-18 degrees C to -20 degrees C) for up to 10 weeks. Survival, as indicated by changes in viable counts, was best in minced beef followed by sausage mixture and TSY broth. Metabolic injury was minimal in each substrate whereas structural injury was detected, especially in TSY broth. Recovery, as indicated by changes in viable counts during thawing at room temperature, was generally complete after thawing 10 g or 10 ml amounts for 2 h. Viable counts obtained after thawing at refrigerator temperature for 24 h were similar to those obtained after 2h at room temperature. For specimens containing low inocula of salmonellae (0.5 cells/g), more isolations were obtained with pre-enrichment than with direct enrichment for minced beef and sausage mixture.

An outbreak of food-borne Campylobacter jejuni infection and the possible role of cross-contamination.

A point-source outbreak or campylobacter infection affected 24 of 51 delegates attending a business lunch. Failure to detect any specific vehicle for the infection led to observations of kitchen practice. Experiments demonstrated that cross-contamination as a result of handling raw and cooked food consecutively was a possible cause of the outbreak.

Versatile collapsible rabbit cage.

The cage was designed for holding and breeding rabbits, and can also be used for holding cats for short periods. Single cages can be joined back to back: this larger cage can also be used for breeding rabbits, and the longer-term holding of cats. When not in use cages fold into compact units, saving storage space and labour, as many cages may be autoclaved, boiled or steamed at once. Repair, maintenance and replacement costs of the cages are lower than for conventional cages.

Isolations of salmonellas from humans and foods in the Manchester area: 1981-1985.

Isolations of salmonellas from humans and food products are recorded for the period 1981-5 and an attempt has been made to investigate the relationship between serotypes isolated from humans and those from meat products. The predominant serotypes isolated from humans were Salmonella typhimurium, S. enteritidis and S. virchow. S. typhimurium was commonly isolated from a range of meat products. S. derby was one of the most common serotypes isolated from tripe and sausages but was relatively uncommon in humans. Salmonellas were found in less than or equal to 0.5% of most cooked meat products apart from tripe and udder (3.2%) and pet foods (12.4%). Isolations from raw meats ranged from 3% for pork to 28% for poultry. Incidents of salmonella infection in humans in Manchester increased between 1981 and 1984 but decreased during 1985.

Isolations of salmonellas from human, food and environmental sources in the Manchester area: 1976-1980.

A retrospective survey was carried out for isolations of salmonellas from humans, foods and sewer swabs from food-handling premises for the period 1976-80. The predominant serotypes isolated from humans were S. typhimurium, S. hadar, S. virchow and S. agona. Salmonellas were found in less than 1% of cooked pork and poultry products and were not detected in cooked beef or lamb. The isolation rates for cooked offal and cooked open pet foods were 2.1% and 19.7% respectively. Isolation rates for uncooked meats ranged from 5% for beef to 36% for poultry. Most of the uncooked meats were sausages in which the predominant serotypes were S. derby, S. typhimurium, S. heidelberg and S. panama. An attempt was made to investigate the relationship between serotypes isolated from humans and from sausages and sewer swabs. S. typhimurium and S. bredeney were predominant in humans, sausages and sewer swabs whilst S. derby, S. panama and S. give were predominant only in sausages and sewer swabs.

Cytophotometric analysis of basic nuclear proteins during gametogenesis in the free-living nematode Panagrellus silusiae.

The cytochemical staining characteristics of basic nuclear proteins during gametogenesis in both sexes of the free-living nematode Panagrellus silusiae were monitored by absorption microspectrophotometry. During spermatogenesis, the levels of both of the nuclear-bound Sakaguchi and 1-fluoro-2, 4-dinitrobenzene (FDNB) reagents per Feulgen-DNA content increase prior to meiosis and subsequently drop off during spermiogenesis. During oogenesis, the amount of Sakaguchi-protein to DNA ratio rises slightly whereas the FDNB-protein to DNA ratio undergoes a meagre decline. Since the oocyte of Panagrellus accumulates DNA in excess of a 4C DNA equivalent, the relative constancy of the ratio of basic nuclear protein content to DNA amount during oogenesis signifies that these proteins are being continously produced during oocyte maturation. After treatment with alkaline fast green (pH 8.1) the cytoplasmic and nuclear regions of the gonocytes of both sexes yield such an intense reaction that microspectrophotometric measurements could not be taken. The basis of the cytoplasmic staining reaction to the fast green (pH 8.1) dye was not determined. The rapid, highly deterministic programme of embryogenesis in Panagrellus may require a substantial stockpiling of basic nuclear proteins during oogenesis.

Cytophotometric study of nuclear proteins during embryogenesis in two nematode species, Ascaris lumbricoides and Panagrellus silusiae.

Patterns of nuclear protein changes during embryogenesis in two nematode systems: Ascaris lumbricoides and Panagrellus silusiae were examined microspectrophotometrically. In both species, development is accompanied by an extensive loss of basic nuclear protein as noted by the diminished intranuclear binding of both the Sakaguchi reagent and fluorodinitrobenzene chromophore. The alkaline fast green (pH 8.1) procedure stained both nuclear and cytoplasmic regions of interphase cells to a similar extent throughout embryogenesis. In cells at metaphase the chromosomes bound the fast green dye intensely while the cytoplasm continued to give a positive reaction. Relative Feulgen stainability of nuclei during embryonic development varied between species. In Ascaris, the one-celled stage nucleus was Feulgen-negative and the LI juvenile somatic nuclei yielded a mean Feulgen-DNA value which was considerably less than a postdiminution diploid DNA equivilent. In Panagrellus, the nuclei of one-celled stage embryos contain DNA in excess of a 4C quantity which subsequently is reduced during embryonic divisions. As in Ascaris the nuclei of Panagrellus LI juveniles give hypodiploid Feulgen-DNA values. The significance of these changes remains to be determined.

Commercial milk products and indigenous weaning foods in a rural West African Environment: a bacteriological perspective.

Two commercially available baby milks, one 'biologically acidified', the other 'non-acidified', and a traditional weaning food, millet gruel, were prepared and stored under village conditions in West Africa. Increases in total colony count and in number of Bacillus cereus, Clostridium welchii, Staphylococcus aureus and Escherichia coli were determined in these products when stored as commonly practised at ambient temperatures over a period of 8 h. Poor hygiene during preparation was indicated by readily detectable numbers of coliforms and E. coli in freshly prepared samples of each of the milks, though the cooked local gruel seemed less vulnerable in this respect. The rate of increase in the numbers of these organisms was lower in the acidified milk when prepared with unboiled water containing high numbers of coliforms and E. coli. Increases in total colony count and in numbers of Staph. aureus were also less marked in the acidified milk. When food was not eaten soon after preparation the problem of bacterial overgrowth was as great with the local gruel as with the considerably more nutritious reconstituted milks.

Microbiological quality of drinking water from office water dispensers.

A survey of the microbiological quality of water sampled from office dispensers in Merseyside found half of the samples to be either unsatisfactory (23/56) or unacceptable (5/56) in terms of guidelines from the Automatic Vending Association of Britain. Factors that appeared to be linked to unsatisfactory microbiological quality were time between filling and sampling and filling on site.

The relationship between rainfall and well water pollution in a West African (Gambian) village.

Water pollution was monitored in six Gambian village wells over a period of 8 months spanning the 5-month monomodal rains and the pre- and post-rains dry periods. Faecal coliform (FC) and faecal streptococci (FS) counts were high throughout and there was a massive increase associated with the onset of the rains, maximum counts exceeding 5 x 10(5)/100 ml. This pattern was largely sustained throughout the rainy season. Some individual variations in patterns of pollution could be ascribed to well design, in particular lining of the shaft, but no well was protected from the seasonal increase in faecal pollution. The source of the increased pollution appeared to be a flushing in of faecal material of indeterminate or mixed human and animal origin, probably over considerable distances. Peaks of pollution not associated with rainfall episodes could have resulted from the practice of communal laundering in the near vicinity of the wells. Specific pathogens including Salmonella spp. were isolated only intermittently. Attention has been drawn to a problem complicating the standard method for assessing FC counts.

Microbiological standards for water and their relationship to health risk.

Maintenance of the microbiological quality of water has been used as an important means of preventing waterborne disease throughout the twentieth century. The commonest microbiological tests done on water are for coliforms and Escherichia coli (or faecal coliform). This paper reviews the legislative and other guidance for microbial standards in drinking and bathing waters and considers evidence for the relationship between the microbiological quality of water and risk to human health. In the past measures of the microbiological quality of water correlated well with risks of acquiring gastrointestinal disease. More recent work suggests that gastrointestinal disease is more strongly associated with the presence of enterococci than of E. coli. New diseases such as cryptosporidiosis have been shown to cause outbreaks of waterborne disease when levels of conventional microbiological parameters are satisfactory. In response to this, and because of failure of prosecution in one outbreak, the United Kingdom (UK) Government has introduced new legislation that requires water providers to perform a risk assessment on their water treatment facilities and to implement continuous monitoring for cryptosporidium. A new European directive on drinking water has been introduced and legislation on cryptosporidium in drinking water has been proposed in the UK.

Bacterial contamination in traditional Gambian weaning foods.

Although emphasis on infant feeding is rightly being placed on breast-feeding, the need for safe weaning foods for the developing world must also receive its due attention. Traditional weaning foods used for young infants in a typical West African village can be as hazardous, bacteriologically, as commercial milk products, and providing a breast-fed child with supplements under the conditions which prevail in much of the developing world is potentially dangerous, whatever the source of the food.

PIP: This study focuses on weaning foods for young infants in a village in Gambia. These foods are potentially hazardous bacteriologically as are commercial milk products. Infants in the village of Keneba are traditionally breastfed for the first 18 months but supplemental weaning foods (initially watery cereal gruels) are introduced after 3 months. These foods were tested at regular intervals after cooking and during different seasons for 5 different bacteria. Water was also examined for the presence of certain bacteria. Results indicated that when intake of breastmilk fell, body weight fell below standard and gruels were increasingly used as supplements. Diarrhea became commonplace by 6 months. It was established that these gruels were heavily contaminated with potentially pathogenic microorganisms and investigations showed that the millet flour itself was contaminated as was the water used in cooking it. Even the feeding bowl displayed evidence of bacteria. Freshly prepared commercial baby milks were compared to the freshly prepared local gruel and were found similar. Clearly, traditional foods as well as imported foods are subject to marked bacterial contamination. The best advice would be to give babies only freshly prepared foods; this is difficult however considering the other demands on mothers' time. It is thus incumbent upon food scientists and nutritionists to develop better weaning foods which are quick and easy to prepare and which should either be of a liquid or semisolid consistency. Since these weaning foods are also nutritionally inadequate, supplements should be made to closely resemble breastmilk; breastmilk must be the reference standard for any substitute food intended for the young infant.