Agar Strips Research Articles

Study of the Antimicrobial Activity and Synergistic Inhibitory Activity of Carica papaya leaves extract with Antibiotics on Escherichia coli

Street food is one of the major causes of diarrhoea and gastrointestinal infections. Escherichia coli are one of the major contributors for many gastrointestinal infections. Natural sources are used to derive drugs that play striking role in the prevention and treatment of human diseases. Ayurveda has described Earandakarkati (Carica papaya) in many digestive disorders. This study was carried out to show the antimicrobial activity of Erandakarkati (Carica papaya) leaves extract alone and in combination with the antibiotics including Penicillin, Erythromycin, Piperacillin and Norfloxacin using agar strip diffusion method to see whether they produce synergistic or an antagonistic effect against street food isolated Escherichia coli and diarrhoeal ETEC strain (as a control). Carica papaya leaves extract showed antibacterial effect. The only combination of papaya leaf extract with Piperacillin resulted into a synergistic effect while the other combinations exhibited an antagonistic effect.

SOYBEAN AS AN ALTERNATIVE NUTRIENT MEDIUM FOR Bacillus subtilis GROWTH

Nutrient agar is a commonly used medium for the isolation and growth of a broad range of microorganisms. The feasibility of using soybean as a base medium in the development of alternative growth media was assessed in this study. Nutrient agar was used as a standard guide to evaluating the performance of the formulated soybean agar. Bacillus subtilis was inoculated and allowed to grow on nutrient agar and soybean agar. Their growth was compared within 24 h after inoculation based on the morphology of individual colonies formed on both media and the pattern of bacterial growth. Our results showed that soybean agar had comparable performance to nutrient agar as the morphological characteristics of B. subtilis colonies formed on both media are generally identical in terms of texture, margin, optical properties, colour, elevation, and shape. However, due to the similar appearance of the bacterial colonies and the soybean agar, the colonies formed on the soybean agar were slightly larger than those formed on nutrient agar. In addition, our findings also revealed that agar strips formed the best soybean agar compared to gelatin and agar powder. Ultimately, this study has shown that locally available soybeans and agar strips can be easily formulated as an alternative to commercial nutrient agar and have great potential for bacteriological research.

A preliminary investigation on airborne fungi of pedestrian underpasses

Pedestrian underpasses are the unique environment where air transaction with outdoor is complicated, inducing interest to study the air quality for the presence of microbes. Thus, the study on the presence of airborne fungi from 11 different underpasses in Chennai city was conducted. The airborne fungi was monitored by exposing potato dextrose agar strips in reuter centrifugal sampler (RCS). A total of 1735 colonies were isolated from underpasses and the control site recorded only 1255 colonies. Total average colony forming unit of underpasses and control site was 157.7 CFU/m3 of air and 114.09 CFU/m3 of air, respectively. Altogether 22 species classified in 16 genera were isolated from both the environments. Of which 21 species belonging to 16 genera were isolated from underpasses whereas the control site yielded 15 species belonging to 12 genera. The isolated species were categorized into three species belonging to Zygomycota, 2 species to Ascomycota and the remaining to Mitosporic fungi. The air sample in the underpass is dominated by the presence of the fungi, Aspergillus flavus, Curvularia lunata and A.niger, whereas the control is dominated by Cladosporium cladosporioides, Aspergillus niger and A. flavus. The study proves the underpasses are a favorite niche for the proliferation of fungal propagules and proper maintenance of underpass is recommended.

Study on Air Bacteria at Different Altitudinal Locations in Tezpur to Tawang Axis

Microflora plays an important role in modulating environmental quality. Among microflora, bacteria are omnipresent in the environment. Pathogenic bacteria, present in air, are known to affect significantly the health and well-being of human, animal or plant populations. Air bacteria monitoring is thus essential for surveillance of pathogenic microorganisms from public health perspective besides its significant implications in detection and mitigation of biothreat related issues. Despite the geo-politically strategic importance of northeast India, there is scarcity of data on human health and disease surveillance. Considering these facts, we, for the first time studied the bacterial diversity of air at six important sites adjacent to the international border in the northeast region of India, having an altitude range of 73 m (Tezpur) to 4170 m (Sela Pass) above sea level. Standard microbiological techniques, such as Tryptone Soya Agar, Mannitol salt and McConkey agar strips and plates were used for air bacterial load assessment and culture for subsequent analysis using biochemical and molecular techniques. Following RFLP study, twenty six different bacterial colonies were isolated. Subsequently, bacteria identification was carried out by examining the substrate utilisation patterns, sequencing 16S rRNA gene and phylogenetic analysis. Results of the study reveal that the isolates mostly belong to two genera Bacillus and Staphylococcus (eleven in each genus), along with Micrococcus, Pseduomonas and Acinetobacter. Based on significant match of our sequences with that of medically important bacterial 16S rRNA sequences available at 16SpathDB 2.0 and review of available literature, we found that a number of these bacterial species have the pathogenic potential. In this manuscript we report our results and discuss the importance of air bacterial surveillance from the perspective of human health, hygiene and biothreat mitigation.

Rapid propagation in vitro and accumulation of active substances of endangered Dendrobium cariniferum Rchb. f

ABSTRACT Dendrobium cariniferum is a valuable ornamental and medicinal plant rich with polysaccharides, alkaloid, and other bioactive compounds, which are potential raw materials for pharmacological utilization. In this study, an efficient protocol for the rapid propagation of D. cariniferum was developed. By using the tissue culture protocol, the effects of pH, hormone combinations, temperatures, light intensity, culture time protocorm proliferation, seedlings rooting, and accumulation of biomass with bioactive compounds were investigated. The experiments showed that the medium [1/2 MS + activated carbon1.0 g/L+ agar strip 7.5 g/L + sucrose 25 g/L] effectively promoted the germination of D. cariniferum seeds. The optimal culture conditions were found at pH 5.7, temperature 23 ± 2°C, and light intensity of 1000 Lx in the protocorm proliferation stage. Adding 1.5 g/L peptone in the medium effectively promoted the seedling rooting. The optimal culture conditions for accumulation of bioactive compounds (polysaccharides and alkaloids) of seedlings were found at temperature of 25 ± 2°C, light intensity of 1500–2000 Lx after the 60-day (d). Our study constructed a rapid propagation system in vitro for D. cariniferum, as well as the methods for efficient accumulation of active substances in seedling culture, which will serve as guidance for industrial production of D. cariniferum seedlings for both medicinal raw materials and ornamental plants. In addition, our study provided a new idea that we can directly use the high bioactive compound seedlings to extract medicinal components in industry conditions without transferring to the field.

Fecal carriage of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. in a Turkish community.

The aim of this study was to determine the prevalence of fecal carriage of extended-spectrum beta-lactamase (ESBL)-producing bacteria, enzyme types, and risk factors affecting colonization. A total of 576 stool samples from outpatients were examined between October 2012 and May 2013. Screening was done with selective EMB plates. ESBL were detected by double-disk synergy and confirmed agar strip gradient methods. Enzyme types were determined by PCR. The prevalence of fecal carriage was found as 30% (173 of 576). Recent use of antibiotics, hospitalization and surgical operation, diabetes, crowded household populations, and old age were associated with higher carriage rates. Of the ESBL-producing bacteria, 87.5% were positive for blaCTX-M genes. Of the blaCTX-M gene-positive isolates, 95.2% were positive for blaCTX-M-1 genes; among these, 82.2% were positive for blaCTX-M-3 and 67.7% were positive for blaCTX-M-15 genes while 62.5% isolates were positive for both blaCTX-M-3 and blaCTX-M-15 genes Conclusions: A high rate (30%) of fecal carriage of ESBL bacteria was found in an adult population. The predominant beta-lactamase enzyme types were CTX-M-3 and CTX-M-15.

Characterization of swiftlet edible bird nest, a mucin glycoprotein, and its adulterants by Raman microspectroscopy.

Edible bird's nest (EBN) is made from the glutinous salivary secretion of highly concentrated mucin glycoprotein by swiftlets (genus Aerodramus or Collocalia) native to the Indo-Pacific region. The unique Raman spectrum of EBN has vibrational lines that can be assigned to peptides and saccharides in the glycoprotein, and it can be used to screen for adulteration. The common edible adulterants classified into two types. Type I adulterants, such as fish bladder, pork skin, karaya gum, coralline seaweed, agar strips, and tremella fungus, were solids which adhered externally on the surface of the EBN cement. They can usually be detected with a microscope based on differences in the surface structure. Type II adulterants were water soluble substances such as saccharides (e.g., glucose, sucrose), polypeptides (e.g., hydrolyzed collagen) and salts (e.g. monosodium glutamate) which can be readily soaked up by the EBN hydrogel when moist and adsorbed internally in the EBN cement matrix forming a composite upon drying, making them difficult to detect visually. The present study showed that Raman microspectroscopy offers a rapid, non-invasive, and label free technique to detect both Type I and II adulterants in EBN.

Bioassay for investigation of auxin transport in single cell layers

Auxin was collected from the cambial region of <em>Pinus sylvestris</em> by applying agar strips to the cut surfaces of stem sections which comprised a single layer of 2 to 4-mm long, mainly intact fusiform cells. Sections of the agar strips were either bioassayed immediately to determine their auxin content or stored for several months at -80<sup>o</sup>C, extracted with 80% MeOH and redissolved in hot agar prior to bioassay. Auxin concentrations were determined by Went's oat coleoptile test, as described by Funke, which was modified considerably to give highly reproducible results. The modifications proved essential for good replication of results and are described in detail together with the use of the bioassay to determine changes in cambial cell polarity during ageing and senescence in <em>P. sylvestris</em>.

Distribution and decline of human pathogenic bacteria in soil after application in irrigation water and the potential for soil-splash-mediated dispersal onto fresh produce

To improve our understanding of the survival and splash-mediated transfer of zoonotic agents and faecal indicator bacteria introduced into soils used for crop cultivation via contaminated irrigation waters. Zoonotic agents and an Escherichia coli marker bacterium were inoculated into borehole water, which was applied to two different soil types in early-, mid- and late summer. Decline of the zoonotic agents was influenced by soil type. Marker bacteria applied to columns of two soil types in irrigation water did not concentrate at the surface of the soils. Decline of zoonotic agents at the surface was influenced by soil type and environmental conditions. Typically, declines were rapid and bacteria were not detectable after 5 weeks. Selective agar strips were used to determine that the impact of water drops 24-87 μl could splash marker bacteria from soil surfaces horizontal distances of at least 25 cm and heights of 20 cm. Soil splash created by rain-sized water droplets can transfer enteric bacteria from soil to ready-to-eat crops. Persistence of zoonotic agents was reduced at the hottest part of the growing season when irrigation is most likely. Soil splash can cause crop contamination. We report the penetration depths and seasonally influenced declines of bacteria applied in irrigation water into two soil types.

Integration of high volume portable aerosol-to-hydrosol sampling and qPCR in monitoring bioaerosols

In this study, the integration of a high volume, portable aerosol-to-hydrosol sampling technique and quantitative polymerase chain reaction (qPCR) was investigated for bioaerosol monitoring by adapting the RCS High Flow to sample air with mineral-oil-strips. Bacillus subtilis var niger and Pseudomonas fluorescens were aerosolized and collected by the RCS High Flow loaded with mineral-oil-strips for 1, 2 and 5 min. In addition, the adapted aerosol-to-hydrosol sampler was also tested for sampling environmental bacterial aerosols in four different environments (a back yard, a student dorm, a dining hall, and a play ground). The performances of the RCS High Flow with mineral-oil-strips were compared with the use of agar strips under similar conditions in all experiments. Air samples collected by the RCS High Flow were cultured, and in addition those collected with mineral-oil-strips were also quantified using qPCR. When sampling B. subtilis var niger aerosols, the use of mineral-oil-strips was shown to report significantly higher culturable concentrations than those obtained by agar strips regardless of the sampling time tested (p-value = 0.04). In contrast, the differences between the two methods when sampling P. fluorescens aerosols were not statistically significant (p-value = 0.5). When coupled with qPCR, the RCS High Flow loaded with mineral-oil-strips obtained significantly higher bacterial aerosol concentrations than those detected by the culturing method. The sampling time was observed to have negligible effects on the efficiency of the technology developed here. When sampling in different environments, the use of mineral-oil-strip was observed to yield significantly higher, about 4-12 times, culturable bacterial aerosol concentration levels compared to the use of agar. This study demonstrated a high volume (100 L min⁻¹) portable aerosol-to-hydrosol sampling technique, holding broad promise in monitoring airborne biological threats when coupled with qPCR technology. Yet, caution should be taken in relating the bioaerosol concentrations to health risks as qPCR detects both culturable and non-culturable cells including inactivated ones.

Effects of Calcium on Growth ofPhysarum polycephalum

Abstract. Physarum polycephalum, a slime mold typically found in decaying plant vegetation, is a member of the class/superclass Myxogastridae. P. polycephalum moves through cytoplasmic streaming due to the interaction between actin and myosin within the walls of its plasmodial tubes. Although early studies indicated that calcium has an excitatory effect on growth, more recent studies showed that the effect of calcium on growth is inhibitory. To determine the direction of the effect of calcium on the growth of P. polycephalum, the organism was grown on agar strips containing various concentrations of CaCl2 for a 72-hour period. Growth was monitored every 24 hours. During the first 48 hours of growth, calcium significantly increased the growth of P. polycephalum. However, in the next 24-hour interval, calcium significantly decreased the growth of the organism. In addition, as the CaCl2 concentration increased, both the enhancement and inhibition of growth became greater. This suggests that the initial effec...

한식당 설비와 기구의 미생물 평가

일반 음식점인 한식당의 시설과 기구의 미생물 오염도를 확인하기 위해 부산지역에서 세곳의 대형한식당을 선정하여 여름기간 중 위생평가를 실시하였다. 총 176개의 Swab 샘플이 식당의 시설과 기구의 표면에서 채취되어 총균수와 대장균군수가 측정되었다. 또한 식당내부의 공기속에 존재하는 총균, 대장균군, 포도상균 그리고 곰팡이와 효모의 오염도를 측정하기 위해 36개의 공기샘플이 채취되었다. 모든 채취된 샘플은 아이스박스에 담기어 실험실로 이송되어 분석되었다. 실험결과 대부분의 Swab된 표면들이 많은 수의 미생물과 대장균군에 의해 오염된 것으로 확인되었다. 미생물의 오염정도는 샘플이 채취된 장소별로 차이가 있었다. 총균수 측정결과 200 ㎠의 단위면적당 검출되지 않는 것에서부터 최고 2.14×10^9의 수치가 관찰되었고 대장균군인 경우에는 검출되지 않은 것에서부터 최고 8.34×10^7의 수치가 검출되었다. 한식당의 공기오염도 측정결과 대부분의 측정지역에서 일반세균, 대장균군, 포도상구균 그리고 곰팡이와 효모가 검출되었다. 미생물에 의해 심각하게 오염된 부분은 바닥, 트렌치, 물병내부, 플라스틱 소쿠리, 고무장갑, 선반 그리고 포장되지 않은 물수건으로 확인되었다. 이러한 장소는 위생표준작업기준의 관리점으로 지정하여 중점적으로 관리되어야만 할 것이다. 또한 식중독사고의 발생위험을 감소시키기 위해서 육안검사와 더불어 주기적인 미생물 검사가 식당의 오염도가 높은 장소에서 수행되어져야만 할 것이다.

Short Term In vitro Culture of Cryptocaryon irritans, a Protozoan Parasite of Marine Fishes

Attempts were made to cultivate Cryptocaryon irritans in vitro at 23-25°C. Attachment of theronts and subsequent enlargement into trophonts were achieved in two experiments using strips of trypticase soy agar (TSA, supplemented with 3% NaCl) as an attachment substrate in filtered seawater. In the third experiment, transformation of theronts into trophonts was achieved in an enriched liquid medium composed of 50% filtered seawater, 30% Leibovitz L-15 and 20% fetal calf serum without attachment onto the TSA. Sizes (mean pSD) of the trophonts, 114.6 p 57.9 μm to 295.9 p 130 μm, were from a recorded size range (50 to 700μm) of the parasite in vivo. Although only limited numbers of theronts (0.28-1.71%) transformed into trophonts, these results showed that the in vitro culture of C. irritans is potentially feasible as evidenced by the enlargement of the trophonts within the in vivo size range using either a solid medium as an attachment substrate or a liquid medium without attachment. There is a need, however, to determine essential factors that influence the transformation of the trophonts into viable tomonts capable of producing theronts.

Mycofumigation with Muscodor albus and Muscodor roseus for Control of Seedling Diseases of Sugar Beet and Verticillium Wilt of Eggplant.

Mycofumigation is the use of antimicrobial volatiles produced by fungi such as Muscodor albusitalic and M. roseus for the control of other organisms. Sugar beet (Beta vulgaris L.) stand establishment was increased and disease severity decreased by mycofumigation with M. roseus and M. albus in autoclaved soil infested with Rhizoctonia solani, Pythium ultimum, or Aphanomyces cochlioides. Eggplant seedlings (Solanum melongena L.) transplanted into autoclaved soil infested with Verticillium dahliae and mycofumigated with M. albus and M. roseus had significantly less disease (P < 0.05) after 4 and 5 weeks compared with nonmycofumigated Verticillium-infested soil. The effect of formulation on efficacy of mycofumigation with M. roseus was tested using potato dextrose agar strips, alginate capsules, ground barley, pesta granules, and stabileze granules. The stabileze and ground barley formulations of M. roseus resulted in the best control of P. ultimum damping-off. The best control of A. cochlioides damping-off was with the stabileze formulation, and the stabileze, ground barley, and agar strip formulations provided similar control of R. solani damping-off. In soil infested with P. ultimum, mycofumigation with M. albus stabileze formulation resulted in stand establishment similar to that in the autoclaved soil. Mycofumigation was ineffective in controlling Fusarium wilt of sugar beet. Neither M. albus nor M. roseus affected sugar beet or eggplant growth or appearance except in the stabileze formulation, where stunting was noticed. Mycofumigation with M. albus and M. roseus shows promise for control of soilborne diseases caused by P. ultimum, A. cochlioides, R. solani, and V. dahliae.

Patterns of splash dispersed conidia of Fusarium poae and Fusarium culmorum

Splash dispersal of Fusarium culmorum and Fusarium poae spores was studied, using inoculated straw placed on tiles as the inoculum source to infect agar strips and artificially produced leaves. In addition, patterns of spread were studied with spores from inoculated artificial leaves onto agar strips. Observed patterns of spore dispersal for each species were indistinguishable, although F. culmorum produced fewer colonies than F. poae. Furthermore, spore dispersal from inoculated straw and artificial leaves were essentially identical, with one exception; colonies arose from single conidia when spread from artificial leaves, but consisted of clumps of conidia when derived from inoculated straw. Splash dispersal patterns of both species onto the upper- and undersides of artificial leaves were different. On the upperside of the leaf, most colonies were found at the tip, while on the underside of the leaf most colonies were found at the base of the leaf. This is the first time that artificially produced leaves have been used in splash dispersal experiments.

Sudden infant death syndrome and Canadian Aboriginals: bacteria and infections

Aboriginal populations in Canada, America and Australia have higher incidences of sudden infant death syndrome (SIDS) than non-Aboriginal groups. Canadian Aboriginal populations (known also as first nation, native or Indian) experience infant morbidity/mortality rates 3–7 times that of non-Aboriginals, with upper track respiratory infection and SIDS recorded as the leading causes. The aim of this investigation was to examine the home environment of Aboriginal infants, particularly during winter months when respiratory tract infections and SIDS are more common. Environmental bacteria, fungi and air particulates were examined in the residences of Aboriginal infants during visits to individual homes on an Aboriginal reserve. The physical histories of SIDS victims were gathered from medical files. Air and surfaces were sampled by agar strips which were processed by a commercial laboratory. The levels of fungi, bacteria and air particulate rates recorded in the reserve homes of Aboriginal infants registered levels considered to be detrimental to the health of the inhabitants. Such extreme levels could contribute to the high incidence of respiratory disease and SIDS experienced by Canadian Aboriginal infants.

Sudden infant death syndrome and Canadian Aboriginals: bacteria and infections.

Aboriginal populations in Canada, America and Australia have higher incidences of sudden infant death syndrome (SIDS) than non-Aboriginal groups. Canadian Aboriginal populations (known also as first nation, native or Indian) experience infant morbidity/mortality rates 3-7 times that of non-Aboriginals, with upper track respiratory infection and SIDS recorded as the leading causes. The aim of this investigation was to examine the home environment of Aboriginal infants, particularly during winter months when respiratory tract infections and SIDS are more common. Environmental bacteria, fungi and air particulates were examined in the residences of Aboriginal infants during visits to individual homes on an Aboriginal reserve. The physical histories of SIDS victims were gathered from medical files. Air and surfaces were sampled by agar strips which were processed by a commercial laboratory. The levels of fungi, bacteria and air particulate rates recorded in the reserve homes of Aboriginal infants registered levels considered to be detrimental to the health of the inhabitants. Such extreme levels could contribute to the high incidence of respiratory disease and SIDS experienced by Canadian Aboriginal infants.

ALLELOPATHIC INTERACTIONS BETWEEN SPONGES ON A TROPICAL REEF

Competition for space among organisms on tropical reefs has often been hypothesized to be mediated by allelopathic interactions, but the secondary metabolites involved in these interactions have rarely been identified. On Guam, the sponge Dysidea sp. overgrows the sponge Cacospongia sp. and causes necrosis. Using field assays, we tested the effects of crude organic extracts and a major sesquiterpene isolated from Dysidea, 7-deacetoxyolepupuane, on Cacospongia and on the production of the major terpenoid metabolites scalaradial and desacetylscalaradial by Cacospongia. We also tested whether the amounts of organic compounds produced by Dysidea differed in the presence or absence of Cacospongia. To determine whether 7-deacetoxyolepupuane had another ecological function, we tested the compound as a predator deterrent. In field experiments, crude extracts of Dysidea and pure 7-deacetoxyolepupuane both caused necrosis in Cacospongia when they were incorporated into agar strips and placed in contact with Cacospongia for 7 d. Organic extract, scalaradial, and desacetylscalaradial concentrations in Cacospongia were not affected by the overgrowth of Dysidea. However, a greater quantity of organic extract (but not scalaradial or desacetylscalaradial) was found in portions of Cacospongia covered by agar strips containing Dysidea organic extracts than in portions of Cacospongia covered by control agar strips. The production of 7-deacetoxyolepupuane by Dysidea occurring on rock substrates and on Cacospongia did not differ; thus, the production of this compound is not induced by the presence of competitors. In addition to its role in competition, 7-deacetoxyolepupuane deterred predation by a spongivorous fish, illustrating the multiple ecological roles that a single secondary metabolite may play.

Splash dispersal of conidia of Fusarium culmorum and Fusarium avenaceum

Splash-dispersal patterns of Fusarium culmorum and Fusarium avenaceum conidia were studied in still air by allowing simulated raindrops, 5 mm in diameter, to fall onto stem bases bearing sporodochia. Splash-dispersed conidia were collected on vertical strips of selective agar (100 × 3 cm) placed at distances 10–100 cm from the source. Colonies of F. culmorum and F. avenaceum were observed at maximum heights of 60 and 45 cm, respectively, and at maximum horizontal distances of > 100 and 90 cm, respectively from the source. Most conidia were found close to the source with 82% of F. culmorum and F. avenaceum colonies counted within a height of 20 cm. Seventy and 80% of F. culmorum and F. avenaceum colonies, respectively, were recorded within a horizontal distance of 30 cm. For cases in which a negative exponential model presented in its linear form could be fitted to the observed horizontal and vertical deposition gradients, half-distances of 10·5–13·6 cm and half-heights of 3·9–11·7 cm were obtained for conidia of F. culmorum. Half-distances of 9·2–16·5 cm and half-heights of 4·4–8·4 cm were obtained for conidia of F. avenaceum. These observations are discussed in relation to the epidemiology of Fusarium diseases of cereals, in particular the role of rain in the upward dispersal of Fusarium inoculum from the stem bases of infected plants or infected stubble to ears of winter wheat.

Staphylococci in a whey powder plant environment: an ecological survey as a contribution to HACCP studies

One of the necessary steps in a HACCP study is the listing of all potential hazards associated with a certain production line. Staphylococci may be listed as such when their presence in the final product is unacceptable for public health reasons. Moreover, opportunities for growth in the line or line environment and possibilities for recontamination of the product after an effective heat treatment can also be regarded as potential hazards. As insufficient data concerning the presence of staphylococci in the environment of a spray dryer of a dairy plant were available, the line environment of a whey powder plant was examined. A total of 358 samples (Rodac plates, Biotest air agar strips, swabs and residues) were taken at various places and analysed. Staphylococcus aureus was found in four samples and in only two of four main areas sampled. S. saprophyticus and S. xylosus were predominant in ‘open’ areas. In the ‘closed’, dry area, where personnel entrance and other circulation was restricted, S. haemolyticus was the most frequently isolated species. Before the study was started, the product was incidentally found to be contaminated with a few S. aureus of a specific phage type, which was not related to any isolate found in the line or the line environment. Moreover, the S. aureus isolates, which were isolated 8 months later from a site previously found to be contaminated, were of different phage types. In hygienically operated whey powder lines, staphylococci should not be of much concern. An in-depth HACCP study should, however, be carried out to determine whether critical control points exist and how they could be controlled.