Bacteriological Quality of Ready-Mixed Mink Feed in Finland

Abstract

Frozen samples of Finnish ready-mixed mink feed were analyzed for total bacterial count, the number of faecal streptococci, the coliform count, the number of haemolytic bacteria and the number of sulphite-reducing bacteria. The investigation comprised 242 feed samples from 38 central kitchens and larger private farm kitchens, the combined feed production of which is about 85 % of the yearly feed production of Finland.

Of all samples 48.3 % had a total bacterial count of 10⁶ … 6} × 106 bacteria per g of feed. The total bacterial count was relatively constant during the first four production periods of the year (December-August) and was elevated during the last period (September-November). The percentage of samples containing less than 2.5 × 10⁴ faecal streptococci per g of feed was 49.8 %; 62 % of the samples contained less than 2.5 × 10⁴ coliform bacteria per g. The content of coliform bacteria was lowest during the third production period (May); 48.5 % of the samples contained 5 × 10³ … 10⁵ haemolytic bacteria per g, and 4.6 % were negative. The content of haemolytic bacteria was relatively constant during the whole production year; 52.6 % of the feed samples contained 5 × 10³ … 10⁵ sulphite-reducing bacteria per g, and 17.2 % were negative. The mean content of sulphite-reducing bacteria was lowest during the second production period (March-April).

The results are discussed and compared with corresponding results from Norway and Denmark.

Sammendrag

Djupfrysta prov av finskt minkfoder analyserades för totalantalet bakterier, antalet faekala streptokocker, antalet koliforma bakterier, antatet hemolyserande bakterier och antalet sulfitreducerande bakterier. Undersökningen omfattade 242 foderprov från 38 foderkök och större privata fodertillverkare vilkas årliga foderproduktion motsvarar 85 % av hela landets fodertillverkning.

48,3 % av proven innehöll 10⁶ … 6 × 10⁶ bakterier per gram foder. Totalantalet bakterier var relativt konstant under de fyra första produktionsperioderna (december-augusti) och steg under den sista perioden (september-november). Den procentuella andelen prov innehållande mindre än 2,5 × 10⁴ faekala streptokocker var 49,8 %. Den procentuella andelen prov som innehöll mindre än 2,5 × 10⁴ koliforma bakterier var 62 %. Halten av koliforma bakterier var lägst under den tredje perioden (maj). 48,5 % av proven innehöll 5 × 10³ … 10⁵ hemolyserande bakterier per gram foder och 4,6 % var negativa. Halten av hemolyserande bakterier var relativt konstant under hela produktionsåret. 52,6 % av proven innehöll 5 × 10³ … 10⁵ sulfitreducerande bakterier per gram foder och 17,2 % var negativa. Halten av sulfitreducerande bakterier var som lägst under den andra produktionsperioden (mars-april).

Resultaten diskuteras och jämförs med motsvarande resultat från Norge och Danmark.